• Journal of Microbiology and Biotechnology
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• v.33 no.5
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• pp.662-667
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• 2023

Allantoin is an abundant component of yams and has been known as a skin protectant due to its pharmacological activities. In previous methods for allantoin determination using high-performance liquid chromatography (HPLC), the separation was unsatisfactory. We herein developed a ¹H quantitative nuclear magnetic resonance (qNMR) method for quantification of allantoin in the flesh and peel of yams. The method was carried out based on the relative ratio of signals integration of allantoin to a certain amount of the internal standard dimethyl sulfone (DMSO₂) and validated in terms of specificity, linearity (range 62.5-2000 ㎍/ml), sensitivity (limit of detection (LOD) and quantification (LOQ) 4.63 and 14.03 ㎍/ml, respectively), precision (RSD% 0.02-0.26), and recovery (86.35-92.11%). The method was then applied for the evaluation of allantoin in flesh and peel extracts of four different yams cultivated in Korea.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.66.3-66.3
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• 2019

젊은 천문학자 모임은 한국천문학회의 분과로 국내에서 천문학을 전공하는 대학원생들의 모임입니다. 2019년에 얌은 K-GMT 그룹의 지원을 받아 워크샵을 개최했고 "얌얌 얼굴 좀 보자" 라는 소규모 행사를 진행하여 학생들의 교류에 힘을 썼습니다. 또한 워크샵 기간을 통해 얻은 회원들의 의견으로 학생들의 관측기기 사용을 바탕으로 학생들의 연락망을 구축하여 학술적인 교류를 하고자 합니다. 2019년 4월 12일 제 100회 한국천문학회 봄 학술대회기간에 열린 정기 총회는 많은 회원들이 모여 활발한 교류를 했습니다. 학술 대회에 이후에 2019 부산과학축전에서 IAU 100주년을 기념하고 2021년에 부산에서 열릴 IAU GA 2021을 홍보하는 한국천문학회 부스에서 회원들이 활동했습니다. 이번 가을 학술대회에는 정기총회에 차기 회장단을 선출하는 선거가 있을 예정이니 많은 분들의 참여 부탁드립니다.

• Food Science and Preservation
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• v.17 no.3
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• pp.391-397
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• 2010

Yams (Dioscorea spp.) have been used as medicinal and edible resources worldwide. In the present study, methanol extracts were prepared from various kinds of yam, including D. batatas (Gyeongbuk No. 1 and No. 4), D. alata L. (Gyeongbuk No. 5 and No. 6), and D. bulbifera and D. nipponica, and the antioxidant, antithrombin, and antimicrobial activities of these extracts were evaluated. The water content of the various yams was 54.7~83.2% (D. batatas> D. alata L.>D. nipponica>D. bulbifera) and the methanol extracts contained 0.59-1.59% (w/v) solid matter (D. alata L.>D. batatas >D. nipponica>D. bulbifera). The mean concentrations of total polyphenols, total flavonoids, and total sugars in the different types of yam were 49.82 mg/g, 9.79 mg/g, and 173.81 mg/g, respectively. Analysis of DPPH radical-scavenging activity showed that D. alata L. Gyeongbuk No. 6 had a strong antioxidant capacity (IC50=$142.30{\mu}g/mL$), whereas the other yams showed reduced levels of activity (IC50=371-$486{\mu}g/mL$). D. alata L. Gyeongbuk No. 6 showed a strong antithrombin activity against human thrombin. Upon treatment with a D. alata methanol extract (1.5 mg/mL), thrombin time was increased 7.35-fold compared with that when methanol alone was used. In an antimicrobial activity assay, the D. nipponica extract showed moderate antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Proteus vulgaris, and Salmonella typhimurium. Our results indicate that different varieties of Dioscorea spp., including D. batatas, have useful biochemical attributes, including antioxidant, antithrombin, and antibacterial activities.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.9-15
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• 1995

This study was carried out to investigate the effects of the optimal fertilizer application levels and planting space at different seeding parts on Chinese yam from 1992 to 1993. The results obtained was as follows： The earlist day to emergence was 42~56 days at tuber section, 37~46 days at an aerial tuber, and 50~56 days at an exposed parent material. in turn. The days to emergence were delayed by increasing fertilizer application levels. In the growth of the under-ground parts, vine length was increased in a tuber section, aerial tuber, and an exposed parent material in turn. The tuber section by 60${\times}$20cm at planting space, 56-56-64 Kg/10a at fertilizer application levels was appeared to be good growth among underground parts. As planted close, the growth of tuber section was decreased. The totoal yield was appeared to be increased about 19% in a tuber section planted as 30${\times}$20cm compared with 60${\times}$20cm. In an exposed parent ma-terial, the planting space, 30${\times}$15cm, was increased 10% compared with 45${\times}$15cm, and in an aerial tuber, the planting space, 10${\times}$10cm, was increased about 10% comparing 30${\times}$10cm. Fertilization level(N-$P_2O_2K_2O$) in 56-56-64Kg/10a was increased 39 to 47% comparing 28-28-32 Kg/10a. And the heavy dressing and the close planting space were appeared to be produced the highest yield. In considering commercial quality, the optimal combination between seeding parts and planting space is recommended to improve commercial qualities and high yield.

• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.79-89
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• 1997

Purpose : Neonatal bacterial meningitis is the disease which clinical manifestations are nonspecific and several neurologic complications may occur. We studied neonatal bacterial meningitis, particularly in treatment and prognosis according to causative organisms -gram positive and gram negative bacteria- to assist in treatment of neonatal bacterial meningitis. Methods : We analysed twenty-four cases retrospectively who had been admitted in NICU or pediatric ward in Chung-ang Gil hospital from Jan. 1991 to Jun. 1996, and who had proven causative organisms in culture or latex agglutination[n test in CSF. Results : 1) The ratio of male to female was 2.4: 1. The mean birth weight and gestational age in cases with gram positive bacterial meningitis were $2.91{\pm}0.79kg$ and $38.4{\pm}2.74$ weeks and those in cases with yam negative bacterial meningitis were $3.30{\pm}0.90kg$ and $37.7{\pm}3.33$weeks respectively. There was no significant difference between the two groups. 2) The perinatal predisposing factors were pematurity, mecoinium staining amnionic fluid, matemal diabetes and pregnancy-induced hypertension, etc. The clinical manifestations Were fever, seizure, poor oral intake and fontanel bulging, etc. There were eleven cases with early onset bacterial meningitis(four cases by gram positive bacteria, seven cases by gram negative bacteria), and thirteen cases with late onset bacterial meningitis(seven cases by gram positive bacteria, six cases by gram negative bacteria). There was no significant difference between the two groups in terms of onset. 3) There were eleven cases with yam positive bacterial meningitis and they were coagulase-negative staphylococci(three cases), group B streptococci(three cases), Staphylococcus aureus(two cases), Streptococcus viridans(two cases), and enterococci(one case). And there were thirteen cases with gram negative bacterial menir gitis and they were Escherichia coli(seven cases), Klevsiella pneumoniae(three cases), Pseudomonas aeruginosa(one case), Acinetobactor(one case) and Enterobacter(one case). 4) The initial CSF WBC counts in cases with yam negative bacterial meningitis were significantly higher than those in cases with gram positive bacterial meningitis but the CSF protein and glucose levels were no significant difference in the two groups statistically. 5) The number of cases with abnormal findings in brain ultrasonography was seven in gram positive bacterial meningitis and ten in gram negative bacterial meningitis. 6) There were relatively high sensitivity to penicillin derivatives, the first generation cephalosporin and vancomycin in gram positive bacteria and to the third generation cephalosporin and amikacin in gram negative bacteria. 7) The mortality rate was 20.8%(5 cases were expired or discharged hopelessly). There was no significant difference between the two groups in prognosis. Conclusions : We recommend active treatment in noenatal bacterial meningitis to improve prognosis because the prognosis is poor.

• Korean Journal of Plant Resources
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• v.8 no.2
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• pp.201-207
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• 1995

Chinese yam (Dioscorea Opposita Thanb) has been cultivated as medicinal crop and food. The experiment was carried out to determine the effect of tuber head origin and fertilizer application method on its agronomic characters of shoot and root tuber to get some imformation on its cultivation. The tuber head cultivated were cut from normal or branched root tuber. 37-28-32-2000 : N-P-K-Humus(Kg/10a) by dispersal but 30% N reduction of Con(RN) or strip application on the two-side of hill(SRN), were applied but N and K were given by the above method with the rate of 40% in March, 30% in June and 30% in July. Agronomic characteristics related to shoot and root tuber were measured and their relationship was analyzed. Tuber head origin had no effect on emergence rate, vine length, branch and node of vine, while emergence date of the tuber head from the normal root which showed the greatest emergence rate, vine length and node in Con treatment was earlier than the others. The tuber head from the normal root, furthermore, had greater length and diameter of root tuber harvested from the field and fresh weight per plant of per 10a compared to the tuber head from the branched root, whereas in both the normal and the branched tuber head RN had the worst result in the characters related to tuber yield except tuber diameter. The tuber head from the normal root produced heavier root tuber than that from the branched tuber and SRN had the best economic yield among the application methods, which resulted from production of less branched root tubers and their rate. In both the normal and the branched tuber head, moreover, yield per plant and economic yield were positively correlated to tuber length but negatively done to number. of branch of vine.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.191-197
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• 2018

This study investigated the influence of starch extraction (ST-EX) solutions on the extraction yield and characteristics of Chinese yam (CY) starches from domestic Dioscorea batatas. Ascorbic acid (VitC), $Na_2S_2O_3$, $NaHCO_3$, and $Na_2CO_3$ were used as ST-EX solutions (0.4%, w/v). The extracted CY starches were examined for ST-EX yield, chemical composition, size distribution, X-ray diffraction, solubility, swelling power, gelatinization, and pasting viscosity. The highest ST-EX yield was obtained from $NaHCO_3$, followed by VitC. Lower protein content, relative crystallinity, and gelatinization enthalpy were found in CY starches from alkaline ST-EX solutions ($NaHCO_3$ and $Na_2CO_3$). Size distribution and gelatinization temperature did not generally differ for CY starches from the different ST-EX solutions. Pasting viscosities increased in the order from $Na_2CO_3$ > $Na_2S_2O_3$ > $NaHCO_3$ > VitC ST-EX solutions. Thus, VitC may be most appropriate to extract CY starch from Dioscorea rhizomes, considering its ST-EX yield, total starch content, and variation in pasting viscosity.

• Korean Journal of Plant Resources
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• v.25 no.4
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• pp.387-393
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• 2012

In order to improve storability of subtropical yam produced in South Korea, the major pathogens found during the storage were isolated and identified of the pathogenicity, and rot inhibition effect was studied based on the curing treatment condition. Penicillium sclerotigenum and Penicillium polonicum were identified as major pathogens causing rot in subtropical yam during storage, and P. sclerotigenum had stronger pathogenicity. Only the cut surface which has been made during a harvest and has been made smooth before curing generated a normal callus layer. The cut surface of tuberous root was cured in 95% of relativity humidity for three days at $23^{\circ}C$, and cured at $28^{\circ}C$ and $33^{\circ}C$. The observation of callus layer showed that the $23^{\circ}C$ treatment group had similar color saturation between tuberous root and pellicle, while the groups treated above $28^{\circ}C$ showed clear distinction. The generation rate of callus 0.5mm or bigger was 93 percent at $28^{\circ}C$ treatment, 96% at $33^{\circ}C$ treatment, but was 52% at $23^{\circ}C$ treatment. The conventional curing treatment group that used wind or sunlight at room temperature created little callus layer. The infection rate of pathogens according to the relative humidity inside the storage room was low at 40% and 60% of humidity, and the curing treatment period did not make a difference. When the humidity inside the storage room was 80%, all treatment groups rapidly increased the fungal pathogens. The rotten rate of each treatment was studied after 180 days during which the storage temperature was maintained at $16^{\circ}C$ and relative humidity 60%. While the rotten rate of tuberous root that has been cut in conventional curing treatment based on solar and wind was 43%, the one cured at over $28^{\circ}C$ and created the callus layer was less than 18%. While even a healthy tuberous root showed 25% of rotten rate in the traditional treatment group, the one cured at over $28^{\circ}C$ was less than 10%. The weight loss was 1-6% lower in the forced treatment group than in the conventional treatment group.

• Korean Journal of Medicinal Crop Science
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• v.2 no.1
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• pp.51-59
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• 1994

This study was carried out to investigate the optimal propagation condition through stem node tissue culture of yam supplemented with concentration levels of growth regulators and activated charcoal in 1 /8MS white media. For shoot induction and plant regeneration from yam stem node tissue wre more effectivein combination of auxin, kinetin and activated charcoal than combination of auxin and kinetin. Shoot induction and plant regeneration were more effective in 1/8 medium suplemented with 1AA $2mg\;/\;\ell,\;kinetin\;2mg\;/\;\ell$ and activated charcoal $1g\;/\;\ell$ than in white medium, but in case of white medium, Shoot induction and plant regeneration wre effective in culture medium supplemented with NAAa $4mg\;/\;\ell,\;kinetin\;2mg\;/\;\ell$ and activated charcoal $1g\;/\;\ell$. Growth status in optimal propagation condition from yam stem node tissue brought the results of multiple plant, elongated plant height and increase in number of leaves and roots, but tissue culture effect by kinds of media in number of multiple plant were more effective in 1 /8MS medium than in white medium.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.133-139
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• 2009

Yam (Dioscorea batatas Decne) has been recognized as healthy food due to its various biological activities, such as anti-obesity, anti-constipation, anti-proliferation, anti-mutagenic activity, and decrease of blood glucose and cholesterol level. In this study, the methanol extract and its organic solvent fractions were prepared from dried Dioscorea batatas Decne, and their antimicrobial, antithrombin, and antioxidant activity were evaluated, respectively. The 66.7% of methanol extract was fractioned into water residue, and most of total-polyphenol/total-flavonoids were found in ethylacetate fraction. This ethylacetate fraction at $500\;{\mu}g/disc$ concentration showed strong antibacterial activity against gram-negative and gram-positive bacteria, except Staphylococcus aureus. Antifungal activity was not observed in methanol extract and its fractions. But, strong antithrombin activity was found in methanol extract. At 4.8 mg/mL concentration, thrombin time was 99.5 sec, which is coincides with 30% activity of aspirin, a commercial available antithrombosis agent. The ethylacetate fraction showed strong DPPH scavenging activity ($IC_{50}$ of $80.5\;{\mu}g/mL$), compared to vitamin C ($IC_{50}$ of $15.2\;{\mu}g/mL$). Also, the ethylacetate fraction showed strong SOD-like activity and reducing power, which are coincide with 43% of vitamin C and 82.7% of butylated hydroxytoluene activity, respectively.