Eun Ki Kim

Ferulic Acid Supplementation Prevents Trimethyltin-Induced Cognitive Deficits in Mice

This study’s objective was to clarify the ameliorative effects ferulic acid (4-hydroxy-3-methoxycinnamic acid) has against cognitive deficits and ChAT activation in trimethyltin (TMT) induced, memory injured mice following a 28-d ferulic acid treatment. After administering TMT for 3 d, each mouse performed Y-maze and passive avoidance tests to check immediate working memory performance and cognitive function. The results showed that ferulic acid administration attenuated TMT-induced memory injury and a decline in ChAT activity in the mice. This suggests that ferulic acid might be useful for preventing cognitive dysfunction as well as for boosting the activation of ChAT in dementia.

Effects of Growth Rate on the Production of Pseudomonas fluorescens Lipase during the Fed‐Batch Cultivation of Escherichia coli

Recombinant Escherichia coliwas grown to produce the thermostable Pseudomonas fluorescenslipase by controlling the specific growth rate (μ). At low growth rate (μ = 0.07 h−1), a higher cell density (OD600 = 140) was obtained. By calculating the cell yield on nitrogen, the medium was optimized to prevent inhibition of cell growth by nitrogen unbalance. Acetate accumulated in the broth at the same rate as observed in a chemostat under nitrogen‐limited fed‐batch conditions, but not in a glucose‐limited fed‐batch culture. Postinduction growth rate affected lipase production more than preinduction growth rate. After induction, more lipase was produced at a low growth rate (μ = 0.1 h−1) than at a high growth rate (μ = 0.4 h−1). More lipase was produced at 37 than at 20 °C at a constant growth rate, indicating that temperature affected other factors in addition to growth rate.

Inhibitory effect of Poncirus trifoliate on acetylcholinesterase and attenuating activity against trimethyltin-induced learning and memory impairment.

Various native Korean plants were screened to find an effective acetylcholinesterase (AChE) inhibitor for the treatment of Alzheimer’s disease (AD). Among these plants, the ethanol extract of Poncirus trifoliate was selected for isolating the AChE inhibitor because it exhibited the highest inhibitory activity (47.31%). To separate the active compound from Poncirus trifoliate, solvent partition, open column chromatography, thin-layer chromatography (TLC), and high-performance liquid chromatography (HPLC) were utilized. The putative chemical structure of the AChE inhibitor was identified as methoxsalen by successive analysis with electron ionization mass spectrometry (EI-MS) and 13C/1H-nuclear magnetic resonance (NMR). To confirm the attenuating effect of the Poncirus trifoliate extract against trimethyltin (TMT)-induced neurotoxicity, in vivo behavior tests were carried out. Our findings suggest that the Poncirus trifoliate extract significantly reversed TMT-induced learning and memory impairment. These results demonstrate that the Poncirus trifoliate extract could possess a wide range of beneficial activities for neurodegenerative disorders, notably AD.

Production of lactic acid from food wastes.

Conversion of food wastes into lactic acid by simultaneous saccharification and fermentation (SSF) was investigated. The process involves saccharification of the starch component in food wastes by a commercial amylolytic enzyme preparation (a mixture of amyloglucosidase, alpha-amylase, and protease) and fermentation by Lactobacillus delbrueckii. The highest observed overall yield of lactic acid in the SSF was 91% of theoretical. Lactic acid concentration as high as 80 g/L was attainable in 48 h of the SSF. The optimum operating conditions for the maximum productivity were found to be 42 degrees C and pH 6.0. Without supplementation of nitrogen-containing nutrients, the lactic acid yield in the SSF decreased to 60%: 27 g/L of lactic acid from 60 g/L of food waste. The overall performance of the SSF, however, was not significantly affected by the elimination of mineral supplements.

Decolorization of Melanin by Lignin Peroxidase from Phanerochaete chrysosporium

Melanin was decolorized by lignin peroxidase fromPhanerochaete chrysosporium. This decolorization reaction showed a Michaelis-Mentens type relationship between the decolorization rate and concentration of two substrates: melanin and hydrogen peroxide. Kinetic constants of the decolorization reaction were 0.1 OD475/min (Vmax) and 99.7 mg/L (Km) for melanin and 0.08 OD475/min (Vmax) and 504.9 μM (Km) for hydrogen peroxide, respectively. Depletion of hydrogen peroxide interrupted the decolorization reaction, indicating the essential requirement of hydrogen peroxide. Pulsewise feeding of hydrogen peroxide continued the decolorizing reaction catalyzed by lignin peroxidase. These results indicate that enzymatic decolorization of melanin has applications in the development of new cosmetic whitening agents.

Repeated exposure of human fibroblasts to UVR induces secretion of stem cell factor and senescence

Backgroundu2002 Some of chronic hyperpigmentary diseases, such as melasma, induced by multiple factors including chronic sunlight exposure, can recur even after chemical epidermal removal. Dermal factors may be involved in the pathogenesis of melasma. Changes in dermal fibroblasts resulting from chronic sun exposure might cause melanocytes to synthesize melanin in the epidermis.

Ipomoea batatas attenuates amyloid β peptide-induced neurotoxicity in ICR mice

In this study, the protective effects of 17 Korean native plants against amyloid β peptide (Aβ)-induced oxidative stress were screened using the 2,7-dichlorofluorescin diacetate assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Ipomoea batatas exerted the highest protective effects against oxidative stress and was selected for further investigation. To confirm the protective activity of this extract, the I. batatas extract was fed to ICR mice that had been injected with Aβ to induce neuronal deficits. In these experiments, the extract of I. batatas significantly reversed Aβ-induced neurotoxicity as assessed by the passive avoidance test, a behavioral experiment. Moreover, I. batatas administration reduced the level of lipid peroxidation and increased catalase activities in biochemical studies using the brain tissue of mice. These results indicate that I. batatas might be beneficial against Alzheimers disease, especially by limiting oxidative stress in the brain.

Continuous water toxicity monitoring using immobilizedPhotobacterium phosphoreum

Water toxicity monitoring based on the continuous cultivation ofPhotobacterium phosphoreum is presented. Normally, after 10 days of operation, a dark variant, which emits no light, appears and dominates the population, resulting in a rapid decrase in bioluminescence. Therefore, to overcome this problem, a fluidized-bed reactor is used in which alginate-immobilized cells are grown and leaking cells are continuously released into the effluent. Experimental results revealed that the dominance of dark variants was suppressed inside the immobilized results revealed that the dominance of dark variants was suppressed inside the immobilized beads, thereby mitigating the rapid loss of bioluminescence. Plus, a high dilution rate (1.2 h−1) prevented the occurrence of other microbial contamination in the reactor. The concentration and bioluminescence of the released cells were sufficient to measure the water toxicity for more than 4 weeks.

A stimulatory effect of Cassia occidentalis on melanoblast differentiation and migration

In vitiligo, the active melanocytes in the epidermis are totally missing, whereas melanoblast cells in the outer root sheath of hair follicles are not affected. In an attempt to find potent repigmenting agents for vitiligo therapy, pod extracts of Cassia occidentalis was found to be effective in inducing differentiation and migration of mouse melanoblast cell line. Methanolic extract redissolved in DMSO at 12.5xa0μg/ml was found to cause 3.5- to 3.8-fold melanin induction in melb-a melanoblast cells after 4xa0days in treatment medium. In addition it induced the tyrosinase activity and altered melb-a cell morphology. Transwell migration assay showed the potential of this herbal candidate to induce direct migration of treated cells. To the best of our knowledge, this is the first report investigating the effect of Cassia occidentalis on the differentiation and migration of melanoblast cells. The findings of present study are significant in designing preclinical and clinical studies on the efficacy of C. occidentalis as a stimulant for skin repigmentation in vitiligo.

A successful helium-neon laser and topical tacrolimus combination therapy in one child with vitiligo

Vitiligo is an acquired pigmentation disorder in which the active melanocytes in the epidermis are lost in the involved skin, whereas immature melanoblasts in the outer root sheath (ORS) of the hair follicle are spared (1). Stimulating these melanoblasts to migrate from the ORS, differentiate, and synthesize melanin would rescue vitiligo (1,2). A 16-month-old child presented with hypopigmented patches over the abdomen and inguinal areas over a 6-month period (FIG. 1A). The lesions were accentuated by the examination under Wood lamp. He was diagnosed as vitiligo and was believed to be too young to treat with NB-UVB, and his mother did not want to use a potent corticosteroid ointment on inguinal areas. After discussing treatment options, his parents agreed to start with twice-weekly He-Ne laser treatment (HLA-2000, Laser Therapy System, Hanil Meditech, Korea). Initial follicular repigmentation was noted after 8 weeks (FIG. 1B). However, the inguinal area was unchanged because the folded area was not exposed to the light (FIG. 1C). Therefore, we carefully exposed the folded area to He-Ne irradiation. After 36 treatments with the He-Ne laser, we added 0.03% topical tacrolimus ointment twice daily to promote repigmentation. After 96 treatments with the He-Ne laser, most of the lesion became repigmented (FIG. 1D,E). The physiologic effects of He-Ne laser treatment are attributed to direct biostimulation, which causes the release of various growth factors and promotes the proliferation of exposed cells (2,3). To evaluate the possible mechanism of vitiligo treatment with a He-Ne laser, we investigated the effect of LED, which is a lowlevel He-Ne laser, on the proliferation, migration, and differentiation of melanoblasts using a mouse melanoblast (Melb-a) cell line. We used an LED array of 660 nm with a power intensity of 4.45 mW/cm. LED exposure was given at four different times. Cell differentiation was measured on the basis of melanin content. Compared with the control group, Melb-a cell proliferation and differentiation were not stimulated by LED irradiation (data not shown). The migratory activity of Melb-a cells was determined by assessing the ability of the cells to cross the 8.0-mm migration chambers in transwell cell culture chambers (Costar 3422; Cambridge, MA, USA). After a 72hour incubation, LED treatment significantly increased the number of migrating melanoblasts compared to a-MSH treatment (FIG. 2). This Address correspondence and reprint requests to: Jeonghyun Shin, MD, PhD, Department of Dermatology, Inha University School of Medicine, 7-206, 27, inhang-ro, Jung-gu, Incheon 400-711, South Korea, or email: jshin@inha.ac.kr. Conflict of interest: None declared.