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This study quantified the spatial variation of endophyte infections in wild populations of commercially important Chondrus ocellatus in Korea. We examined the variation of infection across four locations, two tidal heights and life-history stage (gametophyte vs tetrasporophyte). One hundred and fifty fronds were collected from the upper and lower C. ocellatus zones and microscopic examinations were conducted to determine their infection symptoms. Our results showed that the percentage of C. ocellatus populations infected by endophytic algae were very high, ranging from 58 to 99%, in all populations examined. Endophyte infection severity of Hakampo and Manripo populations was significantly greater in the lower Chondrus zones but it was significantly higher in the upper zone of Jungdori population. Tetrasporophytic fronds were more susceptible to infection by endophytic algae than gametophytic fronds. Also, the infection symptoms were more severe in the middle and basal parts of the fronds than in the apical parts. The findings of this study are very informative data for the endophyte abundance in the field population of commercial C. ocellatus.

To examine optimal growth conditions of the edible green alga Caulerpa okamurae, thalli of this species were cut into erect frond (3 cm long) and stolon (5 cm long) fragments. They were cultured in combinations of four temperatures (15, 20, 25, and 30 °C), three irradiances (20, 40, and 80 μmol photons m−2 s−1), four daylengths (8, 12, 16, and 24 h), and seven salinities (15, 20, 25, 30, 35, 40, and 45 psu). After 12 days, maximal relative growth rates (RGRs) for erect fronds (6.78% day−1) and stolons (7.02% day−1) occurred at 25 °C and 40 μmol photons m−2 s−1. At 30 °C, growth differences were found; negative growth for erect fronds and positive growth for stolons, with an average RGR of 1.96% day−1. A daylength of 16 h and salinity of 30 psu were needed for maximal growth of erect fronds and stolons. Stolon exhibited a greater tolerance to high and low temperatures and low salinity than erect fronds. Thalli weight of C. okamurae was increased by increments of stolon length, new erect fronds, and new ramuli. In conclusion, C. okamurae should be cultivated in summer with high seawater temperature (25 °C) and long daylength, in waters of 30 psu, and at a water depth providing 40 μmol photons m−2 s−1. These physiological and growth pattern data are informative for the successful development of commercial cultivation of C. okamurae.

The objective of this study was to examine the effects of temperature and light intensity on growth of female gametophytes of Eisenia bicyclis and Ecklonia cava and responses of these female gametophytes to Fe addition and daylength. Female gametophytes of each species were cultured at four temperatures (10, 15, 20, and 25°C) and under a combination of four light intensities (10, 20, 40, and 80 μmol photons/(m 2 ·s)) with two temperatures (15 and 20°C for E i. bicyclis; 20 and 25°C for E c. cava) to clarify their optimal growth conditions. Growth and maturation of female gametophytes of these two species under a combination of five Fe-EDTA concentrations (0, 1, 2, 4, and 8 μmol/L) and three daylengths (10, 12, and 14 h) were also examined. The growth of E i. bicyclis gametophyte was maximal at approximately 15–20°C, 20 μmol photons/(m 2 ·s), Fe-EDTA concentration of 8 μmol/L and daylengths of 12–14 h. While E c. cava gametophytes showed optimal growth at approximately 20–25°C, 20 μmol photons/(m 2 ·s), Fe- EDTA concentration of 8 μmol/L and daylength of 14 h. Maturation of gametophytes was enhanced at Fe-EDTA concentration of 4 μmol/L for E i. bicyclis and at 2 μmol/L for E c. cava. In conclusion, optimal growth temperatures and Fe-EDTA concentrations for maturation of E i. bicyclis and E c. cava gametophytes were different. Higher optimal growth temperature for E c. cava gametophytes may contribute to its wider geographical distribution compared to E i. bicyclis which has restricted habitats in Korea. This suggests that addition of Fe ion could be used to recover beds of these two species in barren grounds of Korea.

The protective effects of Neorhodomela aculeata methanolic extract (N. aculeata) on IL-1β and IFN-γ induced β-cell cytotoxicity were examined in a rat insulinoma (RIN) cell line and islets. In the cytokine-treated RIN cells, nitric oxide (NO) production was reduced about 94% at 50 μg/ml of N. aculeata and its suppressive effect was ten times greater as compared to other effective oriental herbs, such as C. cinnamoni and A. capillaries. The inhibitory effects of NO production occurred through the suppression of iNOS (inducible nitric oxide synthase) gene expression which has been confirmed with the changes of iNOS mRNA and protein levels. N. aculeata attenuated the cytokine-induced increase in nuclear factor-kappa B (NF-κB) binding activity, p50 and p65 subunit levels in their nuclei, and at inhibitory kappa B alpha degradation in the cytosol. N. aculeata also attenuated the levels of phosphorylated signal transducer and activator of transcription (STAT)-1 and -3 in whole RIN cells as well as the nuclear translocation of the STAT proteins. Therefore, the cytoprotective effects of N. aculeata were possibly mediated through the suppression of NF-κB and STAT pathways. These findings suggest the beneficial effects of N. aculeata when used for the prevention or attenuation of inflammatory and Type 1 diabetogenic processes.