• ALGAE
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• 제31권1호
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• pp.41-48
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• 2016

The clonal seaweed Chondrus crispus (Rhodophyta, Gigartinales) forms extensive stands at low intertidal elevations on wave-sheltered rocky shores of the North Atlantic. This study investigates if this bushy alga acts as a foundation species in such habitats. The abundance (percent cover) of C. crispus, all other algae, and invertebrates was measured in 390 quadrats spanning 350 km of coast in Nova Scotia, Canada. In these low-intertidal habitats, fucoid algae are the largest organisms and can form extensive canopies, but their cover was unrelated to benthic species richness and to C. crispus cover. Species richness, however, increased with C. crispus cover from low to intermediate cover values, showing little change towards full C. crispus cover. Species composition (a combined measure of species identity and their relative abundance) differed between quadrats with low (0-1%) and high (60-100%) cover of C. crispus. High C. crispus cover was associated to more invertebrate species but fewer algal species than low C. crispus cover. However, the average abundance of algal and invertebrate species occurring in both cover groups was often higher under high C. crispus cover, contributing to a higher average richness at the quadrat scale. Overall, only 16% of the observed variation in species richness was explained by C. crispus cover. Therefore, this study suggests that C. crispus acts as a foundation species but with a moderate influence.

• ALGAE
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• 제26권1호
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• pp.51-60
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• 2011

Similar to other species of Gigartinaceae Chondrus crispus has an alternation of perennial, isomorphic gametophytic and sporophytic generations. As these two generations co-exist independently within populations and obtain their resources in a similar manner, intraspecific competition is expected. In populations within the southern Gulf of St. Lawrence, fronds of both generations of C. crispus occur in similar numbers. This equivalency can be related to substratum instability, where the population is dynamic with a high turn-over rate of genets. These observations support a stochastic hypothesis to account for distribution of gametophytes and sporophytes in this area. Along the Atlantic coast of Nova Scotia, where the substratum is stable, gametophytes are overwhelmingly predominant. Gametophytic predominance is greatest in the lower littoral zone where C. crispus is abundant and space is limited. Under the fucoid canopy where "free-space" exists, the gametophyte to sporophyte ratio is lower. Gametophytic and sporophytic fronds are distributed equally among different size-classes and size-distribution is not considered a competitive factor. Previous studies have shown that sporophytic fronds of C. crispus are more susceptible to infections by endophytic algae and other pathogens, and are more heavily grazed by herbivores than are gametophytic fronds. Thus, mechanistic factors are strongly implied in the selection of gametophytes in the Atlantic population.

• ALGAE
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• 제28권1호
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• pp.121-129
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• 2013

Intact phycobilisomes from a wild-type red Chondrus crispus and its vegetatively derived green mutant were isolated by centrifugation through a discontinuous sucrose density gradient. Pigment composition was subsequently characterized by spectrophotometry. Vegetative thalli of the two strains grown together for six months in the laboratory resulted in different pigment profiles. Two pigmented phycobilisome bands appeared in the sucrose gradient of the wild-type alga, a purple coloured one, and a pink one, whereas only a single blue band appeared in the gradient of the green mutant. Spectrophotometric and fluorescence analyses identified the phycobiliprotein composition of the purple band as the typical phycoerythrin-phycocyanin-allophycocyanin complement in the wild-type, but there was no detectable phycoerythrin present in the blue band of the green mutant. Sodium dodecyl sulphate, preparative polyacrylamide gel electrophoresis analysis confirmed the presence of allophycocyanin subunits in all extracts, but firm evidence of an R-phycoerythrin linker polypeptide in the blue band was missing. These results highlight the ability of C. crispus to adapt to a phycoerythrin deficiency by adjusting light harvesting pigment ratios.

• ALGAE
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• 제26권1호
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• pp.61-71
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• 2011

Thirty populations of Chondrus crispus Stackhouse from Nova Scotia were collected during the years 1993 to 2011. Taken from estuaries, wave exposed open coasts, high intertidal rock pools and shallow subtidal habitats, the populations were evaluated for relative abundance of tetrasporophytic and gametophytic life history phases. Over 2,800 thalli were characterized using the resorcinol-acetal test to distinguish the kappa- and lambda-carrageenan containing fronds of gametophytes and tetrasporophytes, respectively. These populations had $77{\pm}5%$ gametophytes (mean ${\pm}95%$ confidence interval), with most populations having gametophyte : sporophyte ratios ranging from 2 : 1 to 9 : 1. No population had a dominance of tetrasporophytes, although two populations had 1 : 1 ratios. A meta-analysis of our data along with previously published accounts showed no significant changes in gametophyte dominance with respect to hypothesized gradients of wave exposure, salinity, or water depth. Significant changes occurred in ratios at five sites where replicate sampling occurred in different years. We conclude that C. crispus in Maritime Canada has a natural ratio of 3 : 1 or greater in stable conditions, and that lower ratios represent recovery from disturbance in which bare substratum is created that is subsequently colonized by carpospores from remaining gametophytic thalli.

• 한국어병학회지
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• 제26권3호
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• pp.265-274
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• 2013

동해안의 3개 정점(삼척, 영덕, 포항)과 서해안의 2개 정점(학암포, 만리포)에서 여름철(7, 8월)에 진두발을 채집하여 생장, 성숙, 배우체와 사분포자체 비율 및 질병에 대한 연구를 실시하였다. 진두발의 체장은 개체군별로 평균 6.10~9.69 cm였으며 만리포에서 최소였고 포항에서 최대로서 동해안 개체가 서해안 개체에 비해 큰 것으로 확인되었다. 개체가 서해안 진두발에 비해 큰 것을 확인하였다. 진두발 개체군의 영양체 비율은 26.7~66.7 %였으며, 영양체를 resorcinol 방법으로 구분한 후 배우체:사분포자체 비율은 동해안에서 1.7:1로 배우체가 우점하였고 서해안에서는 학암포에서 1:1.1, 만리포에서 1:2.3로서 포자체가 번무하였다. 본 연구에서 한국산 진두발은 다양한 질병(백색증과 녹반증 등), 내생조류와 착생조류를 가지고 있었으며, 여름철의 진두발은 건강한 조체는 20~40 %로서 많은 개체가 질병을 가지고 있었다. 진두발은 현재까지 동정되지 않은 사상형 녹조류인 내생하는 Ulvella sp.를 가지고 있었다. 이러한 내생조류는 유럽과 캐나다의 주름진두발에서 관찰되는 감염성 병원체로서 보다 많은 관심과 연구가 요구된다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권2호
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• pp.160-163
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• 2006

A total number of 31 types of seaweed were assessed with regard to their effects on the proliferation of mouse spleen and thymus cells in a culture, using an MTT reduction assay. Acetone:dichloromethane (1:1) extracts of three seaweed plants: Derbesia marina, Sargassum sp., and Hisikia fuziformis, exhibited significantly positive effects on the survival of mouse spleen and thymus cells in vitro. The acetone:dichloromethane (1:1) extracts of Sargassum sp., in particular, much more potent effects on thymus cell activation than did any of the other types of seaweed. However, the methanol extracts of Sargassum ringgoldianium and Chondrus crispus exerted a stimulatory influence only on the proliferation of mouse spleen cells, whereas the methanol extracts of Grateloupia lanceolata exhibited significant cell proliferation properties in both spleen and thymus cells.

• Preventive Nutrition and Food Science
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• 제11권3호
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• pp.177-183
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• 2006

Methanolic and aqueous extracts of 26 red algae species collected from Jeju Island coast were prepared at a high $(70^{\circ}C)$ and a room temperature $(20^{\circ}C)$ and were examined for their cytotoxic activity against 4 tumor cell lines: U-937 (human monoblastoid leukemia cell line), HL-60 (human promyelocytic leukemia cell line), B-16 (murine melanoma cell line) and HeLa (woman cervical carcinoma cell line). $20^{\circ}C$ methanolic extract of Polysiphonia japonica showed cytotoxic activity of over 50% against U-937, HL-60 and B-16 cells. On the other hand, the $20^{\circ}C$ aqueous extract of Scinaia okamurae and $70^{\circ}C$ aqueous extract of Chondrus crispus showed cell growth inhibition activity of more than 50% against HL-60 and B-16 cells. The highest cytotoxic activity was observed in the $20^{\circ}C$ aqueous extract of Scinaia okamurae against B-16 cells (80.55%).

• Journal of Microbiology
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• 제45권6호
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• pp.541-546
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• 2007

Red algae are distributed globally, and the group contains several commercially important species. Griffithsia okiensis is one of the most extensively studied red algal species. In this study, we conducted expressed sequence tag (ESTs) analysis and synonymous codon usage analysis using cultured G. okiensis samples. A total of 1,104 cDNA clones were sequenced using a cDNA library made from samples collected from Dolsan Island, on the southern coast of Korea. The clustering analysis of these sequences allowed for the identification of 1,048 unigene clusters consisting of 36 consensus and 1,012 singleton sequences. BLASTX searches generated 532 significant hits (E-value <$10^{-4}$) and via further Gene Ontology analysis, we constructed a functional classification of 434 unigenes. Our codon usage analysis showed that unigene clusters with more than three ESTs had higher GC contents (76.5%) at the third position of the codons than the singletons. Also, the majority of the optimal codons of G. okiensis and Chondrus crispus belonging to Bangiophycidae were G-ending, whereas those of Porphyra yezoensis belonging to Florideophycidae were G-ending. An orthologous gene search for the P. yezoensis EST database resulted in the identification of 39 unigenes commonly expressed in two rhodophytes, which have putative functions for structural proteins, protein degradation, signal transduction, stress response, and physiological processes. Although experiments have been conducted on a limited scale, this study provides a material basis for the development of microarrays useful for gene expression studies, as well as useful information for the comparative genomic analysis of red algae.

• ALGAE
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• 제37권3호
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• pp.213-226
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• 2022

Aquaculture is one of the fastest growing food producing sectors; however, intensive farming techniques of finfish have raised environmental concerns, especially through the release of excessive nutrients into surrounding waters. Biodiversity has been widely shown to enhance ecosystem functions and services, but there has been limited testing or application of this key ecological relationship in aquaculture. This study tested the applicability of the biodiversity-function relationship to integrated multi-trophic aquaculture (IMTA), asking whether species richness can enhance the efficiency of macroalgal bioremediation of wastewater from finfish aquaculture. Five macroalgal species (Chondrus crispus, Fucus serratus, Palmaria palmata, Porphyra dioica, and Ulva sp.) were cultivated in mono- and polyculture in water originating from a lumpfish (Cyclopterus lumpus) hatchery. Total seaweed biomass production, specific growth rates (SGR), and the removal of ammonium (NH₄⁺), total oxidised nitrogen (TON), and phosphate (PO₄^3-) from the wastewater were measured. Species richness increased total seaweed biomass production by 11% above the average component monoculture, driven by an increase in up to 5% in SGR of fast-growing macroalgal species in polycultures. Macroalgal species richness further enhanced ammonium uptake by 25%, and TON uptake by nearly 10%. Phosphate uptake was not improved by increased species richness. The increased uptake of NH₄⁺ and TON with increased macroalgal species richness suggests the complementary use of different nitrogen forms (NH₄⁺ vs. TON) in macroalgal polycultures. The results demonstrate enhanced bioremediation efficiency by increased macroalgal species richness and show the potential of integrating biodiversity-function research to improve aquaculture sustainability.