• 농약과학회지
• /
• 제19권4호
• /
• pp.428-439
• /
• 2015

Collectotrichum acutaum 에 의해 발생하는 탄저병은 매년 고추 생산에서 수량과 품질을 감소시켜 고추 병해 중 가장 큰 피해를 주는 병해로 알려져 있다. 본 연구는 고추 탄저병 방제 시 유기농업자재와 화학농약의 교호살포로 화학농약의 사용량을 감소시키기 위한 방제 전략을 개발하기 위하여 수행되었다. 고추 탄저병에 대한 유기농업 자재와 화학농약의 교호살포 효과는 실내와 포장에서 확인하였다. 첫 번째로 13종의 미생물농약과 22종의 유기농업 자재들을 대상으로 탄저병 병원균의 생장억제시험과 생물검정을 실시하였다. 시험결과 1종의 미생물농약(Bacillus subtilis QST-713 액상수화제)과 3종의 유기농업자재(유황, 보르도액, 해조류 추출물)에서 탄저병 병원균에 대해 높은 억제효과를 나타내었다. 포장시험에서 유기합성 살균제(Iminoctadine tris+thiram)를 단용처리 하였을 때 89.5%의 방제효과가 있었으며, 반면에 유황, 보르도액, 구리, 해조류 추출물 그리고 Bacillus subtilis QST-713 액상수화제를 단용처리 하였을때에는 33.1-81.0%로 유기합성 살균제와 비교하여 방제효과가 낮은 것으로 조사되었다. 하지만 유기합성 살균제와 유기농업자재를 7일 간격으로 2회씩 교호살포하게되면 유기합성 살균제+보르도액 교호살포는 81.7%, 유기합성 살균제+해조류 추출물은 87.1%의 방제효과가 있는 것으로 확인되었다. 결론적으로 두 가지의 교호살포 방제체계는 화학농약의 살포횟수 및 사용량을 절감 할 수 있는 가능한 방안으로 추천할 수 있을 것이다.

• 한국수산과학회지
• /
• 제32권1호
• /
• pp.42-45
• /
• 1999

미역분말-첨가 미역국수의 지질대사에 미치는 생리적 효능을 구명하기 위하여 SD계 흰쥐에 4주 동안 미역국수 (BA-noodles)를 투여하여 중성지질 (TG), 총콜레스테롤 (TCh), LDL 및 HDL-콜레스테롤, 그리고 동맥경화지수 (AI)에 미치는 BA-noodles의 영향을 평가하였다. SD계 흰쥐에 조제사료로써 4주 동안 사육하면서 $10\%,\;20\%\;40\%$ BA-noodles의 TG의 함량은 $84.78\pm3.52\~91.30\pm3.77$ mg/dl serum로서 대조군 ($99.77\pm4.25$ mg/dl serum: $100\%$ ) 대비 $10\~15\%$정도나 유의적으로 감소하였다. 같은 방법으로 $10\%,\;20\%\;40\%$ BA-noodles의 TCh의 함량은 $87.28\pm4.97\~91.00\pm3.72$ mg/dl serum로서 대조군 ($99.30\pm4.61$ mg/dl serum: $100\%$)대비 $8\~12\%$정도나 유의적으로 감소하였다 또한 $10\%,\;20\%\;40\%$ BA-noodles의 LDL-콜레스테롤의 함량은 $44.20\pm4.21\~46.00\pm4.41$ mg/dl serum으로서 대조군 ($53.75\pm2.18$ mg/dl serum: $100\%$)대비 $15\~18\%$나 유의적으로 감소하였다. 한편 $10\%,\;20\%\;30\%$ BA-noodles 투여군의 HDL-콜레스테롤의 함량은 각각 $25.36\pm1.12\~27.58\pm1.52$ mg/dl serum로서 대조군 ($23.80\pm0.77$ mg/dl serum: $100\%$) 대비 각각 $7\~16\%$정도나 유의적으로 증가하였다. 끝으로 $10\%,\;20\%\;40\%$ BA-noodles 투여군의 AI는 $2.16\pm0.14\~2.59\pm0.17$로서 대조군 ($3.00\pm0.13$ : $100\%$) 대비 $14\~28\%$나 현저히 감소하였다. 이상의 결과에서 볼 때 이들 기능성 미역국수의 투여는 성인병을 효과적으로 억제할 수 있을 것으로 기대된다.

• 한국물환경학회지
• /
• 제22권6호
• /
• pp.1060-1067
• /
• 2006

Water quality in the Daecheong reservoir has been deteriorated by algal bloom due to nutrient supply from the upstream of the Daecheong reservoir after heavy rainfall. Algal bloom is propagated from eutrophicated tributary into the main body of the reservoir according to the hydrological conditions. This study is aimed to estimate the water current and temperature effect by the simulation of dam spill flow control using water quality model, CE-QUAL-W2 in 2003. Water current was resulted in nutrient transport from upstream of main reservoir and nutrients were delivered up to downstream by fast water velocity. Algal blooms occurred in stagnate zone of reservoir downstream as the current of downstream was retarded according to dam outflow control. Consequently water balance in stagnate zone triggered a rise of water temperature in summer. It affected algal bloom in the embayment of the reservoir. The simulation result by outflow control scenarios showed that spill flow augmentation induced in water body instability of stagnate zone so that water temperature declined. It could be suggested that outflow control minimize algal bloom in the downstream in the flooding season as long as water elevation level is maintained properly.

• ALGAE
• /
• 제31권4호
• /
• pp.351-362
• /
• 2016

We investigated a possible reduction in $CO_2$ uptake rate by phototrophic red tide dinoflagellates arising from mixotrophy. We measured the daily ingestion rates of Prorocentrum minimum by Prorocentrum micans over 5 days in 10 L experimental bottles, and the uptake rates of total dissolved inorganic carbon ($C_T$) by a mixture of P. micans and P. minimum(mixotrophic growth), and for the predator P. micans (phototrophic growth; control) and prey P. minimum (phototrophic growth; control) alone. To account for the effect of pH on the phototrophic growth rates of P. micans and P. minimum, measurements of $C_T$ and pH in the predator and prey control bottles were continued until the pH reached the same level (pH 9.5) as that in the experimental bottles on the final day of incubation. The measured total $C_T$ uptake rate by the mixture of P. micans and P. minimum changed from 123 to $161{\mu}mol\;C_T\;kg^{-1}\;d^{-1}$ over the course of the experiment, and was lower than the $C_T$ uptake rates shown by P. micans and P. minimum in the predator and prey control bottles, respectively, which changed from 132 to $17{\mu}mol\;C_T\;kg^{-1}\;d^{-1}$ over the course of the experiment. The reduction in total $C_T$ uptake rate arising from the mixotrophy of P. micans was 7-31% of the daily $C_T$ uptake rate seen during photosynthesis. The results suggest that red tide dinoflagellates take up less $C_T$ during mixotrophy.

• 한국물환경학회지
• /
• 제30권2호
• /
• pp.206-211
• /
• 2014

This study was done to find chemicals adequate to control alkalinity and hardness in order to reduce dissolved phosphorus in water bodies like rivers and lakes. Five chemicals were selected for the study: calcite, lime, dolomite, magnesite, and gypsum. Data were obtained from the calculations with MINTEQ model as a function of dosage variations of each chemical. Findings are as follows: Three out of the five chemicals are found to be effective in reducing the dissolved phosphorus, i.e., calcite, lime, and dolomite. Calcite and dolomite are able to lower the phosphorus concentration up to one thousandth fold whereas lime does one hundred thousandths fold. In viewpoint of pH variation, both calcite and dolomite seem to be safe since the pH does not increase over 8.3 even in case of overdose. In the same circumstance, with lime the pH increases beyond 9 which is considered to be the highest pH level for the protection of water ecosystem. Nevertheless it is recommendable to use lime in case where there are some difficulties in water quality control due to algae blooms.

• ALGAE
• /
• 제18권2호
• /
• pp.145-156
• /
• 2003

Seasonal investigations were conducted to determine the major aquatic environmental factors and the variation of phytoplankton in Pyeongtaek Reservoir in March, June, September, and December 2000. Heavy rainfall mainly occurs from late June to mid-September, and water quality of reservoir was high in the influent zone of stream and riverine zone of reservoir. The biomass of phytoplankton was related to aquatic environmental factors. In particular, its value increased where nutrient concentration was high. Likewise, the increase of turbidity was found to have anthropogenic effects on the varying quantity of phytoplankton. The phytoplankton composition in quantitative survey identified into 43 genera and 71 species. Species numbers of Bacillariophyceae, Cyanophyceae, and Chlorophyceae accounted for 17%, 15%, and 49%, respectively, with the remainder constituting less than 3-7%. The distribution of such phyla also significantly varied according to seasons, accounting for 25%, 37%, 61%, and 14% in March, June, September, and December, respectively. Bacillariophyceae and Chlorophyceae were observed throughout the year, while Cyanophyceae proliferated in June and September. Euglenophyceae and Dinophyceae were prevalent in March and September, while Cryptophyceae occurred in March and December. The succession trend of phytoplankton showed the maximum cell density was followed by Bacillariophyceae (6.8$\times$$10^3$ cells ${\cdot}$ml)$\rightarrow$ Chlorophyceae (3.7$\times$$10^3$ cells ${\cdot}$ml)$\rightarrow$Cyanophyceae (1.3$\times$$10^4$ cells ${\cdot}$ml)$\rightarrow$Cryptophyceae (1.2$\times$$10^3$ cells ${\cdot}$ml). The cell density was the highest in the upstream. Dominant species were composed of Aulacoseira ambigua, Stephanodiscus hantzschii f. tenuis of Bacillariophyceae, Anabaena spiroides var. crassa, Microcystis aeruginosa, Oscillatoria amphibia of Cyanophyceae, Actinastrum hantzschii var. fluviatile, Pediastrum duplex var. reticulatum of Chlorophyceae, Euglena gracilis, Trachelomonas spp. of Euglenophyceae, and Chroomonas spp., Cryptomonas spp. of Cryptophyceae. As a results, seasonal variation of phytoplankton in Pyeongtaek Reservoir was evident in spite of inflow the high concentration of nutrients from watershed streams, because hydrological control and anthropogenic disturbance in reservoir were found to have major effects on the retention time of water.

• ALGAE
• /
• 제20권2호
• /
• pp.121-125
• /
• 2005

The modern integrated fish-seaweed mariculture has been tested to reduce the environmental impacts of an intensive fed culture. To obtain the best seaweed bioremediation performance, the effects of therapeutants used for fish disease control on the selected seaweed species should be considered. As a selected seaweed, Porphyra yezoensis was tested with six commercial antibiotics including erythromycin thiocyanate_A, erythromycin thiocyanate_B, oxytetracycline, doxycycline, pefloxacin, and amoxicillin trihydrate under the batch incubation at a photon flux density of 10 $\mu$mol ${\cdot}m^{-2}\;{\cdot}\;s^{-1}$ at 15$^{\circ}C$. Among the tested commercial antibiotics, erythromycin thiocyanate_A, erythromycin thiocyanate_B, oxytetracycline, and doxycycline showed decreases in Fv/Fm, the photochemical efficiency of photosystem II, with a dose-dependant and time-dependant manner. From the quenching analysis of chlorophyll fluorescence, three differential patterns were observed in the antibiotics-treated Porphyra: (1) high nonphotochemical quenching (NPQ) and low photochemical quenching (qP) in the cases of Erythromycin thiocyanate_B and amoxicillin trihydrate, (2) high NPQ and high qP in the case of pefloxacin and (3) low NPQ and low qP in the case of oxytetracycline. These results indicated that antibiotics affected in various ways on the photosynthetic apparatus, reflecting differential lesion sites of antibiotics. In addition, the rates of ammonium uptake also decreased with a decrease of Fv/Fm in P. yezoensis thalli treated with erythromycin thiocyanate_B and oxytetracycline. Therefore, the four antibiotics mentioned could affect the bioremediation capacity of the selected seaweed species in the integrated fish-seaweed mariculture system due to the decrease of photosynthetic activity and the simultaneous decrease of ammonium uptake.

• 미생물학회지
• /
• 제6권1호
• /
• pp.22-28
• /
• 1968

Chlorella ellipsoidea cells were cultured in an iron, copper, zinc, manganese, molybdenum or boron-free medium. Biosynthetic activities of nucleic acids, protein and phospholipid in chlorella cells, which were growing in a microelement deficient medium were compared with those of the normal cells by measuring the contents of phosphate, amino acids or UV-absorbing substances in the various cell fractions. When the algae were grown in a molybdenum-free medium, the amounts of phosphate in the acid-soluble fraction of the cells increased, whereas the amounts of alkali-stable protein and RNA decreased compared with the normal cells showing that the synthesis of protein and RNA from the early products of photosynthesis was inhibited. When the algae were grown in a boron-free medium, amounts of alkali-labile protein and phospholipid of the cells decreased, while the amount of phosphate in acid-soluble fraction increased compared with the normal cells showing that the biosynthesis of protein and phospholipid from the early products of photosynthesis was retarded. In general, amounts of protein and RNA in the microelement deficient cells significantly decreased compared with those of the normal cells. Phosphate content in the acid-soluble fraction of the algal cell grown in an zinc, copper, molybdenum, or boron-free medium increased considerably, whereas that of the algal cell grown in an iron or manganese-free medium decreased remarkably compared with that of the control. It is considered, therefore, that molybdenum, zinc, copper and boron etc. play an important role in the biosyntbesis of macromolecule from acid-soluble phosphate compounds, in contrast to the principal action of iron and manganese on the photosynthetic process itself.

• ALGAE
• /
• 제30권3호
• /
• pp.217-222
• /
• 2015

Pythium species (Pythiales, Oomycetes) are well known as the algal pathogen that causes red rot disease in Pyropia / Porphyra species (Bangiales, Rhodophyta). Accurate species identification of the pathogen is important to finding a scientific solution for the disease and to clarify the host-parasite relationship. In Korea, only Pythium porphyrae has been reported from Pyropia species, with identifications based on culture and genetic analysis of the nuclear internal transcribed spacer (ITS) region. Recent fungal DNA barcoding studies have shown the low taxonomic resolution of the ITS region and suggested the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene as an alternative molecular marker to identify Pythium species. In this study, we applied an analysis of both the ITS and cox1 regions to clarify the taxonomic relationships of Korean Pythium species. From the results, the two closely related Pythium species (P. chondricola and P. porphyrae) showed the same ITS sequence, while the cox1 marker successfully discriminated P. chondricola from P. porphyrae. This is the first report of the presence of P. chondricola from the infected blade of Pyropia yezoensis in Asia. This finding of the algal pathogen provides important information for identifying and determining the distribution of Pythium species. Further studies are also needed to confirm whether P. chondricola and P. porphyrae are coexisting as algal pathogens of Pyropia species in Korea.

• ALGAE
• /
• 제27권3호
• /
• pp.205-213
• /
• 2012

The thermostability of antioxidant activity of dieckol, a phlorotannin isolated from brown seaweed Ecklonia cava was investigated. The thermostable antioxidant properties of dieckol were evaluated at 30, 60, and $90^{\circ}C$ for 7 days using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activities, and comparing its performance to that of ascorbic acid. The intracellular reactive oxygen species (ROS) scavenging activity and apoptotic body formation were investigated using DCF-DA assay and nuclear staining with Hoechst 33342, propidium iodide and flow cytometry. Dieckol treated at different temperatures during 7 days showed stable scavenging activities on towards DPPH and hydroxyl radicals. In addition, dieckol showed a stable protective effect against $H_2O_2$-induced apoptotic body formation in Vero cells. On the other hand, the radical scavenging activities and intracellular ROS scavenging activities of ascorbic acid, used as a positive control, were significantly decreased at $60^{\circ}C$ and $90^{\circ}C$ from on the 4th day and 3rd days, respectively. In conclusion, the results indicated that food grade antioxidant extracts containing dieckol derived from E. cava remain a stable during the temperatures encountered during the processing of food and cosmetics.