• Korean journal of applied entomology
• /
• v.61 no.2
• /
• pp.319-330
• /
• 2022

Andong is a place to culture the great amount of hot pepper (Capsicum annuum L.) in Korea. This study reports a yearly occurrence (March 31~October 25, 2021) of thrips infesting the hot pepper in Andong. Thrips caught to yellow sticky traps were diagnosed by morphological characters and showed two dominant species: Frankliniella occidentalis and F. intonsa. During this period, a total of 107,874 thrips were caught and included F. occidentalis at about 82%, F. intonsa at about 17%, and the other thrips at about 0.3%. There were two main peaks at May~June and at September~October, respectively, in which the total number of thrips was higher in the second peak and most were F. occidentalis. Interestinly, a low level of thrips occurred during July~August was observed and explained by their susceptibility to high temperatures. A laboratory experiment by exposing thrips to high temperatures showed that thrips were susceptible to temperatures higher than 35℃ and not tolerant to 45℃ for 1 h. Indeed, high temperatures higher than 45℃ were recorded in the greenhouses in Andong during July~August. F. occidentalis was more tolerant to the high temperatures than F. intonsa. On the other hand, the thrips showed the highest occurrence peak at July~August in hot pepper-culturing greenhouse in Kangwon, where the average temperatures were mostly lower than those of Andong and no high temperatures higher than 45℃ were recorded during July~August. A viral disease caused by tomato spotted wilt virus (TSWV) was observed in the hot peppers cultured in Andong greenhouses. Multiplex PCR was used to detect the virus along with identification of thrips. With a high record of about 30%, the virus-infected thrips were detected during all the monitoring period. The virulent thrips were identified to be only F. intonsa. These results suggest that F. occidentalis gives a direct damage especially during harvesting period with their high populations while F. intonsa gives indirect damage by transmitting TSWV.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.49 no.5
• /
• pp.657-664
• /
• 2016

The green macroalga Cladophora vadorum bloomed along the coast at Sangrok Beach, Buan, South Korea, in September 2015. To elucidate the cause of bloom, the effects of environmental factors on the vegetative growth of adult fragments were examined. Growth experiments were carried out under different combinations of temperatures and irradiances, and with a single factor of nutrients (nitrogen, phosphorus). The maximal growth of C. vadorum was reported under the combination of 25°C and 100 μmol photons m⁻²s⁻¹. The species grew under a wide range of N and P concentrations. The growth of C. vadorum peaked at 50 μM PO₄³⁻, 80 μM NH₄⁺, and 100 μM NO₃⁻. Adult fragments formed holdfasts and new branches within 3 days in culture and became adults, showing polarized growth patterns, in 2 weeks. This is the first report showing the development of numerous bladelets from a segment in Cladophora species. The present results indicate that Cladophora blooms appear under growth conditions that are favorable in terms of temperatures, irradiance, and nutrients via fragment growth patterns producing rapid holdfasts and many bladelets.

• ALGAE
• /
• v.35 no.2
• /
• pp.123-131
• /
• 2020

Sargassum macrocarpum is a rich source of anti-inflammatory compounds. Recently, one of the compounds, tuberatolide B, has been reported as a functional anti-inflammatory additive for foods and nutraceuticals. The artificial seeding, growth and maturation of S. macrocarpum were investigated from May 2018 to September 2019. Indoor culture experiments for induction of egg release were conducted at temperatures of 17, 20, 23, and 26℃ and irradiances of 0, 10, 20, 40, and 80 μmol photons m^-2 s^-1 under 14 : 10 h (L : D) photoperiod. Within a given treatment combination, higher temperatures and irradiance levels favoured the maturation of receptacles in S. macrocarpum. Using artificial temperature and irradiance control, thalli matured one month earlier than thalli in nature. Under natural condition, receptacle formation began in April, and the eggs were released in June and July. The release of eggs from the receptacles was promoted at 17-20℃ and 40-80 μmol photons m^-2 s^-1, and the fastest growth of germlings occuring at 15-17℃ and 40 μmol photons m^-2 s^-1. For mature thalli, 300 g wet-weight was sufficient to seed 100 m of seed string. Thalli grew to 10.5 ± 2.6 cm in length at a density of 6.7 ± 3.3 individuals m^-1 after 1 year of cultivation, from germination. This study demonstrates that it is possible to cultivate S. macrocarpum for the production of anti-inflammatory products.

• Korean Journal of Environmental Biology
• /
• v.38 no.1
• /
• pp.61-70
• /
• 2020

A eukaryotic microalga was isolated from seawater in Janghang Harbor, Korea and its morphological, molecular, and physiological characteristics were investigated. Due to its simple morphology, no distinctive characters were found by morphological observation, such as light microscope or scanning/transmission electron microscopy (S/TEM). However, molecular phylogenetic evidence inferred from the concatenated small subunit (SSU) 18S rRNA and internal transcribed spacer (ITS) sequence data indicated that the isolate belonged to the newly described Micractinium singularis. Furthermore, it was clustered with Antarctic Micractinium strains and it also showed a psychrotolerant property, surviving at temperatures as low as 5℃. However, its optimal growth temperatures range from 15℃ to 25℃, indicating that this microalga is a mesophile. Additionally, gas chromatography-mass spectrometry (GC/MS) analysis showed that the isolate was rich in nutritionally important omega-3 polyunsaturated fatty acid, and high-performance liquid chromatography analysis (HPLC) revealed that the high-value antioxidant lutein was biosynthesized as an accessory pigment by this microalga, with glucose as the major monosaccharide. Therefore, in this study, a Korean marine M. singularis species was discovered, characterized, and described. It was subsequently added to the national culture collections.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.38 no.6
• /
• pp.347-352
• /
• 2005

These experiments investigated the conditioning pattern and the nitrification efficiency of a fluidized sand biofilter (FSB) for seawater application. The FSB fed artificial nutrient was fully conditioned within 22 weeks. The maximum nitrification efficiency of the FSB was achieved at a superficial water velocity (SWV) of 1.0 cm/sec. After fixing the superficial water velocity at 1.0 cm/sec, the nitrification rates of the FSB were assessed at 3 total ammonia nitrogen (TAN) loading rates (250, 500, 1,000 g TAN/$m^3$/day) and 3 water temperatures (12, 16, $20^{\circ}C$). The TAN concentration in the simulated culture tank ranged from 2.87 to 9.72 mg/L at TAN loading rate of 1,000 g TAN/$m^3$/day, while that ranged from 0.45 to 1.26 mg/L at TAN loading rate of 500 g TAN/$m^3$/day. The ranges of TAN concentration in the former were too high for aquatic organisms and those in the latter were acceptable. Therefore, the safe TAN loading rate for the FSB in seawater conditions was decided as 500 g TA/$m^3$/day. From these results, daily TAN removal rates (g TAN/$m^3$/day) of FSB under conditions of inlet TAN concentration (C, mg/L) and water temperature (T, $^{\circ}C$) were calculated by the following non-linear multi-regression equation: TAN removal rate: f(z)=-1,311.295+655.714LnT+225.775LnC ($r^2=0.962$).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.3
• /
• pp.296-302
• /
• 2013

The effects of temperature on spore release, growth and photosynthetic efficiency of Lithophyllum yessoense and Hildenbrandia rubra were examined. L. yessoense was collected at Galnam and H. rubra was collected at Gyeokpo, Korea. The experimental temperatures were different for spore release (10, 15, $20^{\circ}C$), sporeling growth (10, 15, 20, 25, $30^{\circ}C$) and photosynthetic efficiency (10, 15, 20, $25^{\circ}C$). All other culture conditions were the same: 34 psu, 12:12 LD and $50{\mu}mol$ photon $m^{-2}s^{-1}$. Spore liberation was maximal at $10^{\circ}C$ for L. yessoense and at $20^{\circ}C$ for H. rubra. After 14 days, the surface area of L. yessoense was 0.031 $mm^2$ at $25^{\circ}C$ and for H. rubra was 0.032 $mm^2$ at $20^{\circ}C$. Sporelings of L. yessoense were a dark-red color and grew in a round shape. In contrast, H. rubra was bright pink and changed from a round shape in the early growth stage to later become flabelliform. Photosynthetic efficiency was highest between $20-25^{\circ}C$ in both species. In conclusion, L. yessoense and H. rubra display different physiological features based on the optimal temperatures for spore release and sporling growth.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.5
• /
• pp.779-784
• /
• 1998

The specific growth rate and production of resting ega of the freshwater rotifer, Brachionus calyciflorus Pallas was investigated at the different temperatures ($20\~30^{\circ}C$). The rotifer was cultured in 250 ml flask and fed on concentrated freshwater Chlorella. Specific growth rate of B. calyciflorus showed higher rate at higher temperature, but maximum density was observed higher at lower temperature, expect at $20^{\circ}C$. The production of resting egg with temperature was showed decrease on the basis on $26^{\circ}C$. The highest number of resting egg per ml and rotifer $10^4$ were 157 eggs and 810 eggs at $26^{\circ}C$, respectively. This result shows that the optimum temperature for mass culture and resting egg production of this freshwater rotifer were $30^{\circ}C$ and $26^{\circ}C$, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.49 no.6
• /
• pp.845-848
• /
• 2016

The effects of temperature and irradiance on the growth of Ulva prolifera O.F. $M{\ddot{u}ller$ (Chlorophyta), which has been used commercially as food in Korea, were examined in laboratory culture to conserve the strain. Experiments were conducted under combined factors of temperatures of 5, 10, 15, 20 and $25^{\circ}C$ and irradiances of 30, 50, 80 and $100{\mu}mol\;m^{-2}s^{-1}$. The maximum growth of the U. prolifera germlings was observed at $20^{\circ}C$ and $80{\mu}mol\;m^{-2}s^{-1}$, and the minimum growth was recorded at $5^{\circ}C$ and $100{\mu}mol\;m^{-2}s^{-1}$. Considering these results, the species appears to survive under wide ranges of temperature and irradiance, although growth is inhibited by high irradiances of over $100{\mu}mol\;m^{-2}s^{-1}$. This appears to be due to the in situ habitat niche of Ulva prolifera, which is the middle to lower intertidal zone. In conclusion, optimal conditions for the long-term conservation of Ulva prolifera can be established under relatively low temperatures ($5^{\circ}C$) and high irradiance ($100{\mu}mol\;m^{-2}s^{-1}$), while the optimal conditions for mass production are $20^{\circ}C$ and $80{\mu}mol\;m^{-2}s^{-1}$.

• Journal of the East Asian Society of Dietary Life
• /
• v.26 no.2
• /
• pp.125-140
• /
• 2016

We analyzed the cultural characteristics of isolated brewing fungi for developing fermentation starters. In a previous study, we collected 87 domestic nuruk, from which 481 fungi strains were isolated and 11 were selected showing improved productivity. After culturing these 11 fungi strains in several types of media, temperatures, carbon and nitrogen sources, Rhizopus sp. grew well in MEA, ME20S, PDA medium while Aspergillus sp. grew well in ME20S and YES. Both Rhizopus sp. and Aspergillus sp. survived well at optimal growth temperatures of 30 and $37^{\circ}C$. Rhizopus sp. utilized lactose, glucose and peptone sources while Aspergillus sp. utilized glucose, mannose, fructose and yeast extract sources. ${\alpha}-Amylase$ activity was excellent in L. ramosa CN044, R. oryzae 82-7(MEB), R. oryzae CN174 and A. oryzae 58-11(WEB) culture extracts. This study suggests that R. delemar 26-4, 58-8 and A. oryzae 78-5, 37-7 might be appropriate fungi strains for fermentation starters based on development of large fungi bodies and their good enzyme activities.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.49 no.6
• /
• pp.487-490
• /
• 2004

Methods for culturing bean sprouts could be divided into two main groups of overspraying and underwatering according to water supplying. The study was done to measure the effect of water supplying method on growth of mungbean sprouts and temperatures inside their culture boxes. The morphological characters, fresh and dry weights were measured on the 6th day after culturing, but temperatures of the boxes were recorded daily by dataloggers. Lateral roots was not formed in the under-watering method (UM) while partially done in the over-spraying method (OM). OM had longer hypocotyl but UM had longer root compared to the other. Two water supplying methods, however, had nearly similar total length adding hypocotyl and root lengths, diameters of middle and upper parts of hypocotyl. OM showed more total fresh weight than UM mainly resulting from increment of hypocotyl fresh weight. The fresh weight increment in OM was caused by relatively higher temperature of culture box compared to UM.