• 수산해양교육연구
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• 제27권6호
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• pp.1593-1601
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• 2015

Two marine algal halymeniacean species were collected from eastern coast of Korea during the survey of indigenous species of algae. One is distinct from other similar species by foliose thalli with irregular shape and several branches and linear proliferations without division. The other is characterized by indistinct midrib, foliose unbranched thalli and refractive ganglioid cells in medulla. These two species are identified as Grateloupia latissima and Cryptonemia yendoi based on the morphological features, respectively. Morphological and taxonomic notes on these species are included in the present study. This is the first record of G. latissima and C. yendoi from Korea.

• ALGAE
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• 제23권1호
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• pp.15-29
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• 2008

Many species in Gymnodiniales, which are unarmored dinoflagellates, are responsible for marine algal blooms and some of them have potent toxin in the cell. Their taxonomy has so far been well-defined, and several genera (e.g. Akashiwo, Gymnodinium, Karenia) have recently been re-described. In Korea, few works have been carried out on their taxonomical and molecular studies. This study focused on comparison of both morphological and molecular characteristics of five unarmored dinoflagellates on Korean coastal water: Akashiwo sanguinea, Cochlodinium polykrikoides, Gymnodinium catenatum, Gymnodinium impudicum and Karenia aureolum (=K. mikimotoi). Morphological characteristics observed here was in good accordance with the original descriptions of individual species. In addition, none of difference was found in morphological comparisons between the Korean and foreign strains. Furthermore, molecular analysis showed that the SSU rDNA sequences were generally identical according to each species. In some distinct features, A. sanguinea, which has generally the same morphological features, were divided into two groups: one was Korean isolates including European isolates, the other was American isolates. In the two groups, the nucleus was positioned differently: middle of the cells in the Korean isolates (GnSg02, GnSg03), near the epicone in American isolates (CCMP1593, CCMP1837). In addition, this was strongly supported by phylogenetic analysis, inferred from the SSU rDNA sequences. K. aureolum (GrAr01) was corresponded to European G. aureolum (=K. mikimotoi) in shape and position of nucleus, chloroplast, however, which is similar to K. digitata in view of having a finger-like sulcus. This was in good agreement with phylogenetic study of these species. G. catenatum have identical morphology except the ridge location, and their genotype of SSU rDNA was also identical to GenBank data of the same species. From this study, we found that the five Korean unarmored dinoflagellates are identical morphological characteristics and genotype to each species of foreign isolates.

• ALGAE
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• 제39권2호
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• pp.75-96
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• 2024

Rhodomonas (Cryptophyceae) and species assigned to this genus have undergone numerous taxonomic revisions. This also applies to R. marina studied here as it was originally assigned as a species of Cryptomonas and later considered a variation of R. baltica, the type species. Despite being described more than 130 years ago, R. marina still lacks a comprehensive characterization. Light and electron microscopy were employed to delineate a strain from western Greenland. The living cells were 18 ㎛ long and 9 ㎛ wide, elliptical in shape with a pointed to rounded posterior and truncated anterior in lateral view. Two sub-equal flagella emerged from a vestibulum, where also a furrow extended. In transmission electron microscopy, the furrow was associated with a tubular gullet and the pyrenoid embedded in a deeply lobed chloroplast. The chloroplast contained DNA in perforations and was surrounded by starch grains. A tubular nucleomorph was enclosed within the pyrenoid matrix. In scanning electron microscopy, the inner periplast consisted of rectangular plates with rounded edges and posteriorly these were replaced by a sheet-like structure. The water-soluble pigment was Crypto-Phycoerythrin type I (Cr-PE 545). A phylogenetic inference based on SSU rDNA confirmed the identity of strain S18 as a species of Rhodomonas as it clustered with congeners but also Rhinomonas, Storeatula, and Pyrenomonas. These genera formed a monophyletic clade separated from a diverse assemblage of other cryptophyte genera. To further explore the phylogeny of R. marina a concatenated phylogenetic analysis based on the SSU rDNA-ITS1-5.8S rDNA-ITS2-LSU rDNA region was performed but included only closely related species. The secondary structure of nuclear internal transcribed spacer 2 was predicted and compared to similar structures in related species. Using morphological and molecular signatures as diagnostic features the description of R. marina was emended.

• ALGAE
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• 제21권1호
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• pp.109-124
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• 2006

Responses to various types of mechanically induced wounding were followed in the giant-celled Caulerpalean species, Derbesia tenuissima, using time-lapse video-microscopy. Gametophyte vesicle cells. Puncture wounding: the gametophyte cell seals the puncture in 5 min. This is followed by cycles of ruptures and sealing, ending with full recovery in 24 hrs. Cut wounding: the protoplast immediately retracts away from the wall and reforms an intact, deflated protoplast that expands to fill the original cell within 21 hrs. Crush wounding (internal). When retained within the cell wall many protoplast fragments condense, round up, and coalesce; the reconstituted protoplast expands until it attains complete recovery, filling the original cell shape in 12 hrs. Crush wounding (external). Protoplast fragments extruded from the crushed cell are more numerous and smaller taking longer to recover. Most fragments become spherical, transforming into small viable cells capable of reproduction in several days. Sporophyte filaments. Crush wounding creates many small fragments that initially condense, coalesce and then expand within the wall to restore a complete filament with normal cytoplasmic streaming within 5 hrs. Reproduction: gametophyte. Our culture isolates produce more females than males (30:1). Gametangia develop one day before discharge that occurs explosively (1/6 sec) at first morning light. The vesicle cell forms successive gametangia every 14 days. Sporophyte. Each sporangium develops on a lateral branch that becomes isolated by the creation of successive basal plugs. After cytoplasmic cleavage and differentiation the stephanokont spores are discharged. The spores settle quickly and germinate forming gametophyte cells.

• 한국양식학회지
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• 제7권1호
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• pp.9-20
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• 1994

전복을 육상에서 사육하기 위한 시설형태 및 적절한 사육밀도의 구명을 위해 수조형태 및 수용밀도별 사육실험을 한 결과 1. 수조형태, 단별에 따른 성장과 생존율의 차리는 인정되지 않았고, 유수식과 순환식사육의 비교에서는 유수식의 성장도와 생존율이 좋았다. 2. 수조단수별 (3단)에 따른 성장과 생존율의 차이가 인정되지 않아 동일량의 사육수로 단위면적 당 3배의 생산이 가능하였다. 3. 밀도별실험에서 $1000-2000마리/m^2$로 수용한 각장 약 20mm치패는 수용밀도에 따른 성장 차가 없었지만, 각각 200-600, 100-300마리의 밀도로 수용한 각장 약 40mm와 50mm의 치패는 수용밀도가 낮을수록 성장이 빨랐다. 4. 일간섭식률과 사료전환효율은 밀도가 낮을수록 높았고, 치패 크기가 작을수록 높았다

• 한국물환경학회지
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• 제24권1호
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• pp.1-6
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• 2008

Biological and chemical sensors are the two most frequently used sensors to monitor the water resource. Chemical sensor is very accurate to pick up the types and to measure the concentration of the chemical substance. Drawback is that it works for just one type of chemical substance. Therefore a lot of expensive monitoring system needs to be installed to determine the safeness of the water, which costs too much expense. Biological sensor, on the contrary, can judge the degree of pollution of the water with just one monitoring system. However, it is not easy to figure out the type of contaminant with a biological sensor. In this study, an endeavor is made to identify the toxicant in the water using the shape of the chlorophyll fluorescence induction curve (FIC) from a biological monitoring system. Wem-tox values are calculated from the amount of flourescence of contaminated and reference water. Curve fitting is executed to find the representative curve of the raw data of Wem-tox values. Then the curves are digitalized at the same interval to train the neural network model. Taguchi method is used to optimize the neural network model parameters. The optimized model shows a good capacity to figure out the toxicant from FIC.

• 한국지구과학회지
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• 제35권5호
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• pp.305-312
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• 2014

A number of coated grains (spherical to elongated ones in shape) were collected from a small stream, Dijon, France. They were characterized by typical concentric lamination surrounding broken twigs, and were thus identified as concentric precipitation on plant twigs. Within carbonate coatings of the plant twigs, two morphological groups including, eukaryotic green algae (Vaucheria sp.) and cyanobacteria (Scytonema sp. and Rivularia sp.) were detected, which form carbonate crystals that are surrounding their filaments. The filaments could have triggered carbonate precipitation by photosynthetic removal of $CO_2$ causing the increase of alkalinity of the water, and by supporting their sheaths as nucleation sites. Such encrusted twigs were found from 70 meters downstream, in which temperature and pH were measured as $11.1^{\circ}C$ and 8.18, respectively. These water chemistries ($11.1^{\circ}C$ and pH 8.18), with the aid of microbial photosynthesis, were likely to provide a suitable condition for carbonate precipitation on the twigs.

• 한국수산과학회지
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• 제43권5호
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• pp.489-494
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• 2010

The nutritional demand of oyster larva (Crassostrea gigas) were investigated to determine the optimal culture conditions and improve micro-algae utilization. Changes in nutrients and shell growth were examined in fed and 96-h (48 h in late umbone stage) oysters at four larval stages. Shell growth increased significantly in D shape larvae, regardless of feeding variations. No growth was observed in starved larvae, except in shell length of umbone (to 11.9 ${\mu}m$). Fed larvae showed significant growth in all development stages (P < 0.05). During starvation, lipids were most significantly decreased in all larval stages (by 76.8%, 68.3%, 76.3%, and 40.3%, respectively), followed by protein (41.1%, 31.1%, 33.1%, 16.7%) and nitrogen-free extracts (40.8%, 24.3%, 36.9%, 20.1%), Gross energy (kcal/g) consumption in each larval stage was 49.6%, 35.1%, 39.1%, and 20.4%, respectively. Our results indicate that lipids are the most important energy source during the early larval development stages of C. gigas.

• ALGAE
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• 제29권2호
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• pp.75-99
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• 2014

A small dinoflagellate, Ansanella granifera gen. et sp. nov., was isolated from estuarine and marine waters, and examined by light microscopy, scanning electron microscopy, and transmission electron microscopy. In addition, the identity of the sequences (3,663-bp product) of the small subunit (SSU), internal transcribed spacer (ITS) region (ITS1, 5.8S, ITS2), and D1-D3 large subunit (LSU) rDNA were determined. This newly isolated, thin-walled dinoflagellate has a type E eyespot and a single elongated apical vesicle, and it is closely related to species belonging to the family Suessiaceae. A. granifera has 10-14 horizontal rows of amphiesmal vesicles, comparable to Biecheleria spp. and Biecheleriopsis adriatica, but greater in number than in other species of the family Suessiaceae. Unlike Biecheleria spp. and B. adriatica, A. granifera has grana-like thylakoids. Further, A. granifera lacks a nuclear fibrous connective, which is present in B. adriatica. B. adriatica and A. granifera also show a morphological difference in the shape of the margin of the cingulum. In A. granifera, the cingular margin formed a zigzag line, and in B. adriatica a straight line, especially on the dorsal side of the cell. The episome is conical with a round apex, whereas the hyposome is trapezoidal. Cells growing photosynthetically are $10.0-15.0{\mu}m$ long and $8.5-12.4{\mu}m$ wide. The cingulum is descending, the two ends displaced about its own width. Cells of A. granifera contain 5-8 peripheral chloroplasts, stalked pyrenoids, and a pusule system, but lack nuclear envelope chambers, a nuclear fibrous connective, lamellar body, rhizocysts, and a peduncle. The main accessory pigment is peridinin. The SSU, ITS regions, and D1-D3 LSU rDNA sequences differ by 1.2-7.4%, >8.8%, and >2.5%, respectively, from those of the other known genera in the order Suessiales. Moreover, the SSU rDNA sequence differed by 1-2% from that of the three most closely related species, Polarella glacialis, Pelagodinium bei, and Protodinium simplex. In addition, the ITS1-5.8S-ITS2 rDNA sequence differed by 16-19% from that of the three most closely related species, Gymnodinium corii, Pr. simplex, and Pel. bei, and the LSU rDNA sequence differed by 3-4% from that of the three most closely related species, Protodinium sp. CCMP419, B. adriatica, and Gymnodinium sp. CCMP425. A. granifera had a 51-base pair fragment in domain D2 of the large subunit of ribosomal DNA, which is absent in the genus Biecheleria. In the phylogenetic tree based on the SSU and LSU sequences, A. granifera is located in the large clade of the family Suessiaceae, but it forms an independent clade.

• 환경생물
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• 제34권3호
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• pp.183-192
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• 2016

지금까지 개발된 나노물질 중 은나노물질은 일상 생활제품에 가장 많이 활용된 나노물질 중 하나로 알려져 있고 다양한 경로를 통해 환경에 유입되어 환경 및 인체에 부정적인 영향을 미칠 수 있는 것으로 알려져 있다. 화학물질과 달리 나노물질은 물리화학적 특성에 따라 동일 나노물질이더라도 그 유해성이 다르다고 알려져 있지만 기존 연구들은 다양한 특성을 동일 시험조건에서 평가하기 보다는 하나의 특성에 대해 독성을 보고하는 수준에 그치고 있다. 따라서 기존 연구들의 서로 다른 시험생물, 시험조건, 나노물질 특성 등을 고려할 때 나노물질의 물리화학적 특성에 따른 독성의 체계적인 비교평가가 어려운 한계가 존재한다. 본 연구는 은나노물질의 다양한 물리화학적 특징에 따라 수생생물에 미치는 독성영향을 평가하고자 한다. 대표적인 3종 (어류, 물벼룩, 조류)의 수생생물에 대한 은나노물질의 입자상 크기 (50, 100, 150 nm), 형태 (입자형, 선형), 코팅물질 종류 (PVP, citrate)에 따라 생태독성평가를 진행하였다. 연구결과, 나노 물질의 크기가 작을수록 그리고 입자상 형태보다 선형에서 독성이 비교적 높게 나타났다. 특히 선형 은나노의 경우, 길이에 비례하여 그리고 입자에 비해 비교적 높은 독성을 나타냈다. 반면, 은나노의 코팅물질 종류는 대상 수생생물에 따라 독성의 영향이 다르게 평가되었다. 본 연구는 은나노물질의 다양한 물리화학적 특성에 기인한 독성을 동일한 시험 조건, 시험생물에서 체계적으로 비교 평가하였다는 점에서 의의가 있으며 본 연구결과는 은나노물질의 환경 및 인체 위해성평가 자료로서 활용될 수 있을 뿐 아니라 보다 안전한 은나노물질 소재개발을 위한 과학적 자료로서 활용될 수 있을 것으로 사료된다.