• ALGAE
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• 제27권2호
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• pp.125-134
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• 2012

Germanium dioxide ($GeO_2$) has been used for many years in the cultivation of red and green algae as a means of controlling the growth of diatoms. Brown algae are sensitive to $GeO_2$, however, the basis of this sensitivity has not been characterized. Here we use embryos of $Fucus$ $vesiculosus$ to investigate morphological and physiological impacts of $GeO_2$ toxicity. Morphometric features of embryos were measured microscopically, and physiological features were determined using pulse amplitude modulated (PAM) fluorometry. At 5 mg $L^{-1}$ $GeO_2$, embryos grew slower than controls and developed growth abnormalities. After 24 h, initial zygote divisions were often oblique rather than transverse. Rhizoids had inflated tips in $GeO_2$ and were less branched, and apical hairs were deformed, with irregularly aligned, spheroidal cells. Minimum fluorescence ($F_0$) showed minor differences over the 10 days experiment, and pigment levels (chlorophylls $a$, $c$ and total carotenoids) showed no difference after 10 days. Optimum quantum yield increased from ca. 0.52 at 24 h to 0.67 at 5 days, and $GeO_2$-treated embryos had higher mean values (significant at 3 and 5 days). Optimum quantum yield of photosystem II (${\Phi}_{PSII}$) was stable in control thalli after 5 days, but declined significantly in $GeO_2$. Addition of silica (as $SiO_2$) did not reverse the effects of $GeO_2$. These results suggest that $GeO_2$ toxicity in brown algae is associated with negative impacts at the cytological level rather than metabolic impacts associated with photosynthesis.

• ALGAE
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• 제27권2호
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• pp.109-114
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• 2012

Water motion is one of the main drivers in morphological variability in species within de order Laminariales, and most of our current knowledge is based on subtidal populations. $Eisenia$ $arborea$ is a dominant kelp species in the North Pacific, widely distributed along the Baja California Peninsula from mid intertidal down to subtidal areas. This species presents great variability in the intertidal zone but it has not been yet evaluated such variability according to wave exposure. The present work also identifies the spatial / temporal variation, particularly respect to the presence of stipes without medulla (hollow stipes) a feature common among other brown seaweeds. We evaluated the effects of wave action in morphological variation of intertidal $Eisenia$ $arborea$ (Laminariales, Ochrophyta) at Punta Eugenia. The spatial and temporal variation sampling was surveyed between February, May, July, and August 2004 in the intertidal of Punta Eugenia, Baja California Sur. Our results have shown that exposed sites correlate with increased length and width of stipes as compared to more protected sites. Hollow stipes frequency changed more in association with temporal variation than with spatial heterogeneity suggesting nutrient limitation for thalli development. Our results suggest that $Eisenia$ $arborea$ compensate by morphological modifications the stress of living in the intertidal zone by showing larger stipes. Hollow stipes might be are also a mechanical adaptation to increase survival in high energy environments.

• 한국수산과학회지
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• 제38권2호
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• pp.112-117
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• 2005

Sargassum fulvellum (Turner) C. Agardh, an edible brown alga is farmed commercially by sexual reproduction and vegetative regeneration. Investigations were made on the phenology, abundance and maturity of reproductive structures in mature fronds, egg release and young germling development under different light conditions (20, 50, 80 and $100{\mu}mol/m^2/s$) and temperatures (5, 10, 15, 20 and $25^{\circ}C$). Monthly sampling was carried out by SCUBA diving at Chungsando on the southwestern coast of Korea from September 2002 to August 2003. The Maximum length of thalli was $104.6{\pm}20.7{\cal}cm$ in March 2003 when the water temperature was $9.0^{\circ}C$ and minimum was $0.8{\pm}0.5{\cal}cm$ in June when the water temperature was $19.5^{\circ}C$. Receptacle formation was observed from February to April. The peak period of egg release for this alga was in April when the water temperature was about $10^{\circ}C$ in nature. In the culture regimes of temperature and irradiance, the egg release of the excised female receptacle was highly affected by temperature. The maximum rate of egg release was $96.7{\pm}5.8{\%}$ under $20^{\circ}C$ and $80{\mu}mol/m^2/s$. The maximum length of young germlings was $3.9{\pm}0.2{\cal}mm$ after 35 days culture under $15^{\circ}C$ and $80{\mu}mol/m^2/s$.

• ALGAE
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• 제33권1호
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• pp.55-68
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• 2018

Foliose species of the Bangiaceae (Porphyra s. l.) are very important in Korean fisheries, and their taxonomy and ecophysiology have received much attention because of the potential for developing or improving aquaculture techniques. Although 20 species of foliose Bangiales have been listed from the Korean coast, some of them remain uncertain and need further comparative morphological studies with molecular comparison. In this study, we confirm the distribution of four Pyropia species from the east coast of Korea, Pyropia kinositae, P. moriensis, P. onoi, and P. retorta sp. nov., based on morphology and rbcL sequence data. Although P. onoi was listed in North Korea in old floral works, its occurrence on the east coast of South Korea is first revealed in this study based on molecular data. P. kinositae and P. moriensis, which were originally described from Hokkaido, Japan, are first reported on the east coast of Korea in this study. Pyropia retorta sp. nov. and P. yezonesis share a similar thallus color and narrow spermatangial patches in the upper portion of the frond, and they have a sympatric distribution. However, P. retorta can be distinguished by the curled or twisted thalli and by molecular data. The biogeographic pattern of the two native species, P. kinositae and P. retorta, suggests that the east coast of Korea may have been a place of refugia during the Last Glacial Maximum (LGM), and then recolonized to the northern part of Japan through the restored East Korean Warm Current after the LGM.

• ALGAE
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• 제25권1호
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• pp.1-9
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• 2010

Although Pterocladiella is a well-known agar-producing red algal genus, its taxonomy in Korea appears to be confused. In the present study, we demonstrate the occurrence of Pterocladiella nana and P. tenuis, as well as P. capillacea in Korea on the basis of morphological and plastid rbcL sequence comparisons. P. capillacea commonly occurs along the coasts of Korea and has regular pinnate branches with abundant second-order branches, growing up to 10 cm in length. P. nana occurs in the intertidal zone of Jeju and is distinguished by the small size of its thalli (up to 5 cm) and regular branches with up to third-order branches. P. tenuis is distributed mostly subtidally on the southern coast of Jeju and has irregular branches with rarely second-order branches, growing up to 19 cm in length. We determined rbcL sequences from 19 specimens (15 from Korea and four from France) and downloaded 28 sequences from GenBank. Analyses of all 47 rbcL sequences revealed that each of three species was consistently resolved. P. capillacea and P. tenuis always formed a sister clade with P. nana at the base. Given that 12 rbcL haplotypes from 28 specimens of P. capillacea have been found to date, analysis of a fast-evolving gene from across the range of the species should highlight its genetic diversity.

• 한국균학회지
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• 제22권4호
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• pp.332-337
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• 1994

Under standard condition (Han, et al., 1990: glucose 1%-nitrate 0.1% minimal medium, 30 ml in 9 cm plate, $10^6$ cells of inoculum per plate), wild type of Aspergillus nidulans developed both sexual and asexual organs in ballance, while velA1 mutant developed asexual ones preferentially. Increase of glucose concentration did not significantly affect the asexual sporulation. However, development of sexual organs were largely affected. It was greatly enhanced when favorable nitrogen source, for example, casein hydrolysate was added, which is contrary to the case of Neurospora or Saccharomyces where limitation of N source induces sexual development. On most of moderate C sources asexual development in $velA^+$ strain was largely inhibited except acetate on which only asexual spores were produced, while that in velA1 mutant strain was not affected. Lactose promoted the sexual development even in velA1 mutant indicating that lactose itself or its metabolic intermediate may induce sexual development independent of allelic state of velA gene. On other moderate favorable C sources, glycerol, galactose and ethanol, asexual development was largely inhibited in $velA^+$ strain but not in velA1 mutant strain. Sexual organs were, however, never produced on acetate. These results suggested that asexual development of wild type is largely dependent on C sources and the velA gene is involved in the repression of asexual development in not-enough-grown (non-competent) thalli resulting in preferential progression of sexual development.

• 한국수산과학회지
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• 제38권3호
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• pp.164-171
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• 2005

Codium fragile (Suringar) Hariot, an edible green alga is farmed in Korea by natural blooming zygotes attachment. Experiments were conducted to reveal the conditions for artificial seed production of C. fragile by sexual and asexual reproduction. Growth was compared between zygotes attachment (sexual reproduction) and isolated utricles with medullary filaments (asexual reproduction). Zygotes and isolated utricles with medullary filaments were cultured under different light conditions (10, 20, 40, 60 and $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and temperatures (5, 10, 15, 20 and $25^{\circ}C$) under 16:8LD. Maximum growth of zygote was $261.3{\pm}21.0\;{\mu}m$ under $15^{\circ}C$ and $20\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ after 13 days culture. Maximum regeneration of isolated medullary filament was $8.1{\pm}1.7\;mm$ per one isolated utricle under $20^{\circ}C$ and $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ after 15 days culture. After intermediate culture during two months in the field, morphogenesis occurred in both sexual and asexual reproduction, and growth of young thalli was not significantly different (p>0.05) between the both reproduction methods. Even though seed production of C. fragile is possible in both sexual and asexual reproduction, the mass artificial seed production of asexual reproduction is much more effective than that of sexual reproduction that is too much affected by maturity.

• 한국양식학회지
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• 제16권1호
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• pp.44-50
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• 2003

가시파래의 자연 서식지에서 자연채묘 방법과 실내에서 포자방출에 의한 인공종묘생산 기술을 개발하고, 양성시험에 의한 완전한 양식방법을 개발하여 대량생산 가능성을 조사하였다. 가시파래 자연채묘는 자연 서식지의 사니질로 조성된 해역이 적합하였으며, 하계의 착생밀도는 채묘틀이 지면에서 20cm 높이에 시설하는 것이 높았고, 추계에는 40cm 높이에 시설하는 것이 효과적이었다. 가시파래 인공종묘 생산은 성숙한 모조를 12~24시간 음건하여 포자를 방출하고, 포자액이 들어있는 수조에 채묘망을 넣고 24시간 암흑처리하면 포자 착생률이 높게 나타났다. 가시파래 양성은 수심이 낮고 저질이 니질 또는 사니질로 조성된 해역은 지주식으로 시설하며, 수심이 깊고 유속이 빠른 해역은 부류식으로 시설하는 것이 좋았다. 양성장소는 영양염이 풍부하고 파랑에 의한 엽체의 탈락과 시설물 파손이 적은 해역이 양호하였으며, 광합성률을 높이기 위하여 표층노출식으로 시설하는 것이 생산량이 많았다.

• 한국양식학회지
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• 제2권1호
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• pp.33-41
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• 1989

본 연구는 1984년 4월부터 1985년 3월까지 채집된 충무 연안산 청각을 대상으로 포낭의 형태 및 성숙 시기를 구명하기 위하여 수행되었다. 조사지역의 수온은 $7.5\~25.4^{\circ}C$ 였으며, 염분은 $32.9\~34.5\%_{\circ}$로 나타났다. 배우자낭은 조사한 전기간을 통하여 출현하였다. 6$\~$11월에 조사된 조체들은 모두 성숙 또는 미성숙한 배우자낭을 가지는 신장된 형태의 포낭이 많았다. 대부분의 조체가 자웅이체 이었으며, 일부가 자웅동체로 암배우체 보다는 숫배우체의 출현율이 높았다. 동계에 채집된 조체들 중 일부는 절두형 또는 신장된 형태의 포낭을 가진 것이 많았으며, 하나의 포낭에 암, 수의 배우자낭을 함께 가진 조체가 출현하였고 하나의 포낭에서 파생된 또 다른 포낭을 볼 수 있었다.

• 한국양식학회지
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• 제12권1호
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• pp.7-14
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• 1999

갈래곰보의 원혈질체 분리와 배양 조건을 확립하여 생명공학기술에 의한 유전적 형질개량의 기초조건을 마련코자 하였다. Abalone acetone powder,소라의 내장조효소, Pseudomanas와 Vibrio의 조효소, Cellulas R-10, Macerozyme R-10, Hemicellulase, Pectinase, Driselase, Protease 등을 0.6M mannitol과 0.5% potassium dextran sulfate를 함유한 50mM MES 해수완충액(pH 6.0)에 단독 또는 조합하여 조제한 효소액을 갈래곰보의엽체에 처리하였을 때 Abalone acetone powder 4.0% + Macerozyme R-10 4.0% + Hemicellulase 4.0% 효소조합액의 처리로서 생체조직 1g당 $107.6{\times}10^4$개의 원혈질체를 분리시킬 수 있었다. 갓 분리한 원형질체는 투명한 타원형으로 $7{\mu} m$~ $24{\mu} m$의 범위에 분포하였다. 0.2M mannitol을 첨가한 $ASP_{12}$배지에 배양한 세포는 9일 후 분열되고 25일 후 발아하였다. $ASP_{12}$배지는 f/2배지보다 갈래 곰보의 원혈질체 배양에 효과적이었으며 Guillard 항생물질조합액의 처리는 분화에 장애가 되었다.