• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.37 no.2
• /
• pp.185-197
• /
• 1992

Differences in the amount and chemical characteristics of the epicuticular waxes on rice leaves were studied for the active tillering and heading stages of rice varieties differing widely in gross leaf-surface property and genetics. The amount of waxes on surfaces of rice leaf-blades was determined by extraction with chloroform and chemical composition of the waxes was characterized by thin layer chromatography, gas liquid chromatography and infrared spectrophotometry. The amount of waxes varied by variety and significantly with growth stage. The amount at the heading stage was 1.7 to 3.6 mg/g fresh weight of leaves, which was two to three times as much as that at the tillering stage of 0.8 to 1.8 mg/g fresh weight. The waxes consisted of seven chemical classes, namely diols, fatty acids, fatty alcohols, fatty aldehydes, fatty esters, saturated and unsaturated hydrocarbons. Diols and unsaturated hydrocarbons were identified as new chemical classes of the rice epicuticular waxes. The polar constituents such as dials, fatty acids and fatty alcohols and the non-polars such as fatty aldehydes, fatty esters, and saturated and unsaturated hydrocarbons were identified at the heading stage, but at the tillering stage only the non-polar compounds were identified. In the carbon numbers (C) of the chemical classes, diols were composed entirely of C30 and acids were mainly of C30 and C31. In alcohols, primary alcohols were composed of C13 and C32, and the secondary alcohols were of C14, C16 and / or C30 regardless of the rice varieties. The acid portion of fatty esters, mainly composed of C22 and C23, showed low cabon numbers compared with the aldehydes. The alcohol portion of them showed a wide distribution in carbon numbers from C13 to C26 depending on the rice varieties. Hydrocarbons had odd carbon numbers, consisting mainly of C29 and C31.

• Horticultural Science & Technology
• /
• v.32 no.5
• /
• pp.673-683
• /
• 2014

This study was conducted to establish an efficient screening method to identify cucurbits resistant to powdery mildew. Powdery mildew fungus was obtained from a single lesion of infected cucumber leaf in 2010 at Daejeon. The fungus was identified as Podosphaera xanthii race 1 based on morphological characteristics and resistance responses of four melon differentials. Development of powdery mildew caused by the fungal isolate on 34 commercial cultivars of cucumber was investigated at three plant growth stages in a greenhouse. The degree of resistance of cotyledons of each cultivar to the fungus was not correlated with that of whole plant, but powdery mildew occurrence in the first true leaf was highly correlated with resistance at the level of the whole plant. Based on these results, the first true leaf of cucurbit cultivars can be used for screening of resistance to powdery mildew. In addition, variation of resistance of commercial 12 cucumber and 26 melon cultivars to the powdery mildew fungus due to different growing seasons was tested. In the case of cucumber, the resistance response in some cultivars was influenced by growing season. The resistant cultivars showed higher resistance in the warm season than in the cool season. By contrast, the resistant melon cultivars demonstrated strong resistance in all the tested growing seasons. Interestingly, the tested powdery mildew pathogen, a member of P. xanthii race 1, was not pathogenic on seven cultivars of watermelon (Citrullus lanatus). To follow up on this, diverse race 1 isolates of P. xanthii should be collected and tested.

• Asian Journal of Turfgrass Science
• /
• v.22 no.2
• /
• pp.171-178
• /
• 2008

We have found the clusters of tiny spiny puffball-like mushrooms growing gregariously in fairy ring (arcs) rimmed by a zone of darker green grass in the golf courses. Macroscopic as well as microscopic characters were examined for the morphology of fruiting body. Exoperidium is thin and densely spiny with minute fibrillae at early stage. The connivent spines were soft and quite persistent. In age, the fibrillae scrumble away with a powdery coating, which leaves white endoperidium becoming pale brown. It's interior was white and fleshy at first, but turns into an olive-colored dust as the gleba, the spore-producing tissue, develops to maturity and loaded with olive-brown spore mass. Then, distinct apical pore developed on the endoperidium. Rudimentary subgleba(sterile base) was narrow, chambered, delineated from the gleba by a membrane in young material. These characters suggested this fungus is a Vascellum, a member of the family Lycoperdaceae. The shapes of the spores were globose, echinulate, $3{\sim}3.5{\mu}m$ in diameter, thick-walled, and olive brown. Capillitial threads were $8-9{\mu}m$ wide, mostly colorless in KOH solution and thin-walled, which designated as "paracapillitium". This is an another character that distinguishes this mushroom from Lycoperdon spp. The spines developed on exoperidium were characteristically connivent; their apices joined together in a point, leaving a space below, which gives the appearance of vault to each group of usually 5 to 6 fibrillae. Based on the above characters, this fungus is identified as Vascellum curtisii (Berkeley). The characters distinguishable this from Lycoperdon pulcherrimum, and Vascellum pretense are discussed in detail. Control trial was also attempted. Strong vertical raking(SVR) followed by applying 500x detergent solution (Spark, Aekyung Co. Seoul) resulted in excellent control over any other treatments. In this plot, fruiting body was not developed throughout the end of mushroom growing season.

• Food Science and Preservation
• /
• v.22 no.3
• /
• pp.437-442
• /
• 2015

In a continuing screening of selected medicinal plants native to South Korea, the antioxidant and pancreatic lipase inhibitory activities of an aqueous methanolic extract from the heartwood of Aquilaria agallocha were investigated. Eighty percent of the methanolic extract of A. agallocha was further divided into $CH_2Cl_2$, EtOAc and n-BuOH in order to yield four solvent-soluble portions, namely $CH_2Cl_2$-soluble, EtOAc-soluble, n-BuOH-soluble and $H_2O$ residue. The antioxidant properties were evaluated by employing radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals, while the anti-obesity efficacy of A. agallocha extracts and solvent-soluble portions were tested by porcine pancreatic lipase assay. All tested samples showed dose-dependent radical scavenging and pancreatic lipase inhibitory activities. Among the tested extracts and solvent-soluble portions, the $CH_2Cl_2$-soluble portion showed much higher radical scavenging activity and pancreatic lipase inhibitory properties when compared with other solvent-soluble portions. This result suggested that there was a significant relationship between the total phenolic content and biological efficacies, and A. agallocha extract might be considered as a new potential source of natural antioxidants and as a pancreatic lipase inhibitory source. A more systematic investigation of this biomass will be performed for further investigation of activity against antioxidative and anti-obesity effects.

• Journal of the Korean Home Economics Association
• /
• v.39 no.1
• /
• pp.91-102
• /
• 2001

The non-starch polysaccharides in the cell wall of rice, glutinous rice, and black rice, were analyzed. They were fractionated into fractions; water-soluble, hot writer-soluble, ammonium oxalate-soluble, sodium hydroxide-soluble, potassium hydroxide-soluble, and the alkali-insoluble, according to the solvent solubility. The dietary fiber contents were 5.4% in glutinous rice, 4.2% in rice and 7.5% in black rice. The sodium hydroxide soluble fibers were abundant in each kind of rice, especially 4.01% in black rice. The water soluble fibers were 80% of dietary fiber in glutinous rice, 66% in rice, 86% in black rice. It was supposed that the content of the water soluble fibers in rice was increased by pounding. Pectic substances in water soluble fibers, hot water soluble fibers, and ammonium oxalate soluble fibers fraction, were 2.4% in glutinous rice fraction,1.59% in rice, and 1.12% in black rice. Alkali soluble fibers were considered as hemicellulose. Black rice contained 5.80% of hemicellulose, which was more than twice as much as glutinous rice(2.58%) and rice(2.22%). Alkali insoluble fibers were considered as cellulose, which showed no considerable difference. Among samples content of uronic acid in glutinous rice, rice and black rice were 0.9%, 0.66%, 1.8% respectively. Uronic acid of black rice was twice more than other samples tested. The fraction of black rice that uronic acid was extracted at most was the fraction of sodium hydroxide. Mono saccharides of the fraction was the glucose, the arabinose, the xylose.

• Food Science and Preservation
• /
• v.15 no.3
• /
• pp.483-490
• /
• 2008

Several tartaric acid-degrading bacteria were isolated from Korean grape wine pomace after enrichment culture at $30^{\circ}C$ for 10 days in liquid media containing tartaric acid Among them, strains KMBL 5777 and KMBL 5778 exhibited the highest level in the growth and tartaric acid degradability in a medium containing 0.2%(w/v) tartaric acid as a sole carbon source. They were identified as Acetobacter tropicalis based on their morphological and physiological characteristics as well as their 16S rDNA sequences. Blast search of the 16S rDNA sequences revealed that the isolated strains are closest to Acetobacter tropicalis. Homologies of the sequences of KMBL 5777 and KMBL 5778 were 96.0 and 98.9%, respectively with those of A. tropicalis LMG 1663. Both the two bacteria showed higher tartaric acid degradation at $25^{\circ}C$ that those at 20 and $30^{\circ}C$. They could degrade tartaric acid at a wide range of pH between 4.0 and 7.0 with the most rapid degradability at pH 7.0. However, when the bacteria were grown for 8 days, the same level of tartaric acid degradation was observed at pH 4.0, 5.0, 6.0 and 7.0, which was 90.0% of degradation of the acid.

• Korean Journal of Agricultural Science
• /
• v.24 no.2
• /
• pp.283-289
• /
• 1997

CNU O4-5 isolated from conventional Meju, which is used as raw material for making a soybean fermentation food, identified as an Aspergillus oryzae. To make koji, Aspergillus oryzae CNU O4-5 was cultured for 3-4 days at $30^{\circ}C$ with various grain materials such as flour, soybean powder, flour+soybean powder(1:1), soaked soybean and rice. The koji was evaluated for analyze the angiotesin converting enzyne(ACE) inhibition, antioxidative activity, superoxide dismutase(SOD) activity, amylase and protease activity. $\alpha$-amylase and glucoamylase activities of flour koji were higher than those of the koji soybean powder. However neutral and alkaline protease activities of flour koji were lower than those of flour+soybean powder and soybean koji. Amylase and protease activities of kojies of soaked soybean and rice showed very low level. The range of the ACE inhibition rate by hot water fraction of the kojies, which are cultured with various gain materials, were from 45% to 54%. The anti oxidative activity of ethanol-fraction of koji, which is made by using the soybean powder or soaked soybean, prolonged for 6 days in lard at $60^{\circ}C$. The SOD activity of grinded fraction of koji, which is made by using the flour or soybean powder, was same as 2,000 units per g of each koji.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.2
• /
• pp.121-129
• /
• 2014

Marine algal flora and community structure were seasonally investigated at four sites in the vicinity of the Igidae on the southern east coast of Korea from May 2010 to February 2011. A total of 66 species including 9 of Chlorophyta, 14 of Phaeophyta, 43 of Rhodophyta were found during the survey period. Among these species, 16 species were found throughout the year. Seasonal mean biomass in wet weight was 123.6 (spring), 2,061.6 (summer), 412.0 (autumn), 678.9 (winter) $g{\cdot}m^{-2}$. Maximum biomass was recorded in summer($2,061.6g{\cdot}m^{-2}$), and minimum was recorded in spring($123.6g{\cdot}m^{-2}$). Spatial maximum and minimum species number were recorded at station 3 and 4(50 species) and at station 1(47 species). At station 1, 2 directly exposure on Yongho and Daeyeon cheon (stream) run off, and discharge from Nambu sewage treatment plants near coastal area, species diversity was relatively low and dominant species were similar throughout four seasons. The R/P, C/P and (R+C)/P value reflecting flora characteristics were 3.07, 0.64 and 3.71, respectively. The flora investigated could be classified into six functional groups such as coarsely branch form 39.39 %, sheet form 30.30 %, thick leather form 13.64 %, filamentous form 12.12 %, crustose form 3.03% and jointed calcareous form 1.52 % during survey period. The number of marine algae species in Igidea were 96 species at 1996 to 1997 and 66 species at 2010 to 2011, respectively. The change of seaweed species is due to the pollution loaded from sewage treatment plant and stream. We thus recommend that the positive maintenance control method like sewage treatment, for the protection of seaweed bed should be proceeded to near coastal area.

• Journal of Life Science
• /
• v.19 no.7
• /
• pp.994-1002
• /
• 2009

A bacteriocin-producing bacterium identified as Bacillus licheniformis was isolated from soybean sauce. Antibacterial activity was confirmed by paper disc diffusion method, using Micrococcus luteus as a test organism. The bacteriocin also showed antibacterial activities against Bacillus sphaericus, Lactobacillus bulgaricus, Lactobacillus planiarum, Paenibacillus polymyxa, and Pediococcus dextrinicus. Optimal culture conditions for the production of bacteriocin was attained by growing the cells in an MRS medium at a pH of 6.5~ 7.0 and a temperature of 37$^\circ$C for 36$\sim$48 hr. Solvents such as chloroform, ethanol, acetone, and acetonitrile had little effect on bacteriocin activity. However, about 50% of bacteriocin activity diminished with treatment of methanol and isopropanol at the final concentration of 50% at 25$^\circ$C for 1 hr. It was stable against a pH variation range from 3.0 and 7.0, but the activity reduced to 50% at a pH range from 9.0 to 11.0. It's activity was not affected by heat treatment at 100$^\circ$C for 30 min and 50% of activity was retained after heat treatment at 100$^\circ$C for 60 min, showing high thermostability. The bacteriocin was purified to a homogeneity through ammonium sulfate precipitation, SP-Sepharose ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (HPLC). The entire purification protocol led to a 75-fold increase in specific activity and a 13.5% yield of bacteriocin activity. The molecular weight of purified bacteriocin was estimated to be about 2.5 kDa by tricine-SDS-PAGE.

• Journal of the Mineralogical Society of Korea
• /
• v.22 no.4
• /
• pp.359-370
• /
• 2009

Arsenic and heavy metals leached out as a result of oxidation of tailings exposed to the surface pose a serious environmental contamination of mine areas. This study investigated how arsenic behavior is controlled by a variety of processes, such as oxidation of sulfides and formation or alteration of secondary minerals, based on mineralogical methods. The study was carried out using the tailing samples obtained from Nakdong mine located in Jeongseongun, Gangwondo. After separating magnetic and non-magnetic minerals using pretreated tailing samples, each mineral sample was classified according to their colors and metallic lusters observed by the stereoscopic microscope. Subsequently, the mineralogical properties were determined using various instrumental analyses, such as x-ray diffractometer (XRD), energy dispersive spectroscopy (EDS), and electron probe micro analyzer (EPMA). The literature review confirmed that various ore minerals were identified in the Nakdong ore deposits. In this study, however, there were observed a few original ore minerals as well as secondary and/or tertiary minerals newly formed as a result of weathering including oxidation. In particular, we did not recognize pyrrhotite which has been known to originally exist in a large abundance, but peculiarly colloform-type iron (oxy)hydroxides were identified, which indicates most of pyrrhotite has been altered by rapid weathering due to its large reactivity. In addition, a secondary scorodites filling the fissure of weathered primary arsenopyrites were identified, and it is speculated that arsenic is immobilized through such a alteration reaction. Also, we observed tertiary iron (oxy)hydroxides were formed as a result of re-alteration of secondary jarosites, and it suggests that the environment of tailing has been changed to high pH from low pH condition which was initiated and developed by oxidation reactions of diverse primary ore minerals. The environmental change is mainly attributed to interactions between secondary minerals and parental rocks around the mine. As a result, not only was the stability of secondary minerals declined, but tertiary minerals were newly formed. As such a process goes through, arsenic which was immobilized is likely to re-dissolve and disperse into surrounding environments.