An intraspecific crossbreeding experiment of Undaria pinnatifida was carried out by reciprocal crossing a natural strain (Kn) sampled from Kagoshima Prefecture (southern site) with an early harvesting cultivar (N1) from the Naruto area, Tokushima Prefecture. Seedlings of four experimental crosses, F1 hybrids (N1 ♀×Kn♂, Kn♀×N1♂) and inbreds (N 1♀×N1♂, Kn♀×Kn♂) by crossing free-living male/female gametophytes that respectively originated from single zoospores, were cultivated at Naruto. The hybrid N1♀×Kn♂ showed better growth for both blade length and blade weight than the two inbreds during the early harvesting period, suggesting heterosis effects on growth of the F1 hybrid. The hybrid N1♀×Kn♂ showed similar growth to the inbred Kn♀×Kn♂ compared to the other inbred N1♀×N1♂, indicating the great influence of male gametophytes on growth. In contrast, the other hybrid Kn♀×N1♂ showed the worst growth rates among all the seedlings. The “southern type”inbred Kn♀×Kn♂ grew much better in size compared to its parent Kn when cultured in the Naruto area. Morphologically, the hybrids showed intermediate characteristics of their parents, but rather closer to the female parent. These findings show that intraspecific crossbreeding of U. pinnatifida between a southern type strain and a cultivar can be an effective method for cultivar improvement for early harvesting.
To develop a simple rapid technique in normal phase partition chromatography for monosaccharide and disaccharide analysis in edible seaweeds, a comparison between a TSKgel NH2-100 column packed with chemically bonded amino-silica gel and a TSKgel Amide-80 column, also packed with chemically bonded amide-silica gel, was carried out. Saccharide chromatographic behavior, resolution, and elution rapidity were evaluated. The anomeric peaks of reducing saccharides split at 25 ℃ and 40 ℃ in a TSKgel Amide-80 column, although they did not split at 40 ℃ in a TSKgel NH2-100 column. An increase of acetonitrile concentration in the mobile phase increased the saccharide retention times. Usually, but not always, increasing the hydroxyl group of saccharides tends to increase the retention time. Saccharide retention times increased mostly in order as follows: deoxyhexose＜pentose＜ketohexose＜aldohexose. Saccharide resolution and peak heights in a TSKgel NH2-100 column were higher than those in a TSKgel Amide-80 column. Thus, a TSKgel NH2-100 column was used as the column for saccharide analysis in this study. The present technique was successfully applied to monosaccharide and disaccharide analysis and should be useful for monosaccharide and disaccharide analysis in edible seaweeds.
We tested the effects of temperature on the growth of cultured Sargassum muticum during the shoot growth stage, during which main branches are produced instead of cauline leaves. Combinations of five temperature conditions (16, 20, 24, 28 and 30℃) with two irradiance levels (saturated and unsaturated levels for growth, i.e., 130 and 20 μmol m-2s-1, respectively) were set to examine whether the growth response to temperature was differed under different levels of irradiance. Under conditions of saturated irradiance, the elongation of the main branch was most rapid at 16 and 20 ℃, but when growth was expressed as weight, there was no significant difference among 16-28 ℃. Under higher temperatures (24 and 28 ℃), leaf formation on branches contributed increases in weight instead of main branch elongation. Under conditions of unsaturated irradiance, growth based on weight was negative at 28 and 30 ℃ due to the loss of leaves, but the main branches remained intact and alive. This was unlike a previously reported case of S. horneri, in which S. horneri died at these high temperatures when the irradiance was insufficient. This tolerance to higher temperatures even under insufficient irradiance is advantageous in establishing communities in enclosed coastal areas of the Seto Inland Sea, where temperature and turbidity of seawater are high during summer.
The edible blue-green alga Nostoc flagelliforme was evaluated for beneficial effect on blood glucose level and serum lipid concentrations in an experiment with SHR rats used as model animals for spontaneously non-insulin-dependent diabetes mellitus. In both of N. flagelliforme powder administered rats and N. flagelliforme extract administered rats, the fasting glucose levels on 21st day, 35th day, 49th day and 63rd day were significantly lower than control rats. The concentrations of triglyceride in the serum of N. flagelliforme powder administered rats and total cholesterol and triglyceride in the serum of N. flagelliforme extract administered rats were significantly lower than those of control rats. The concentrations of triglyceride and total cholesterol in the liver of both of N. flagelliforme powder administered rats and N. flagelliforme extract administered rats were significantly lower than those of control rats. These results indicate that N. flagelliforme has beneficial effects on blood glucose level and serum lipid concentrations in spontaneously non-insulin-dependent diabetic rats.
The edible species of Nostoc are unique cyanobacteria because they can grow in some extreme environments, and some of these species are rare. Anti-hyaluronidase activity and sugar composition of the extracts were compared among five edible Nostoc strains which were cultured using 180 liter large scale reactor. The IC50 against hyaluronidase of the extracts of Nostoc sphaericum, Nostoc flagelliforme and Nostoc verrucosum were 14.4, 46.5 and 56.2 μg mL -1, respectively. These anti-hyaluronidase activities were higher than disodium cromoglycate which is known as an anti-allergic drug and used as a positive control substance. The ratio of glucuronic acid in constituent sugar of N. sphaericum extract was 13.3%, it was the highest among the five strains tested. The extract of N. sphaericum had the highest yield and highest anti-hyaluronidase activity when compared with the other four Nostoc strains.
The effects of the edible blue-green alga Nostoc flagelliforme (Facai) on 1, 2-dimethylhydrazine (DMH)-induced colon tumorigenesis in male Sprague-Dawley (SD) rats was examined. Eighty male SD rats (6 weeks old) were divided into four groups of 20 animals each. Each group of animals was injected subcutaneously with 10 mg kg-1 DMH or saline once a week for 10 weeks and then fed diets supplemented with or without 1% dried alga for 30 weeks. Animals were killed and colon tumors were counted and measured. The numbers of colon tumors induced by DMH in rats fed diets supplemented with and without alga were 23 and 34, respectively. These results demonstrated that the edible blue-green alga N. flagelliforme decreased the number of colon tumors induced by DMH in SD male rats.
In the southern Japanese coastal area affected by the Kuroshio Current, seaweed beds consisting of brown macroalgae has been reduced owing to increases in water temperature and damage from grazing by herbivorous animals. Kami-Koshiki-shima Island, located in western part of Kagoshima Prefecture, contains landlocked brackishwater lagoons, and Sargassum piluliferum is a dominant species in Namako-ike Lake, located in one of these lagoons. In this study, seawater temperature in Namako-ike Lake and neighboring waters was measured in 2014 in order to elucidate the factors contributing to the maintenance of the S. piluliferum populations. The annual average seawater temperature in 2014 was 19.5 ℃ in Namako-ike Lake, with the highest water temperature recorded in July, 2014 at 35.6 ℃ and the lowest water temperature recorded in March, 2014 at 6.6 ℃. These results suggest that S. piluliferum has tolerance to high water temperature in Namako-ike Lake, which is far higher than in surrounding sea areas. The lack of herbivorous animals in the lake is suggested to be the main factor contributing to the maintenance of the S. piluliferum population rather than an increase in water temperature. In order to maintain the S. piluliferum population, it is necessary to continue monitoring the organisms growing in Namako-ike Lake in cooperation with local residents.
History, catch, gear, propagation of resources in the wild, cultivation, and utilization of the kelp Saccharina japonica in northern Hokkaido, Japan, and southern Sakhalin and Primorye, Russia are compared in this review of the fisheries in these areas. Sea currents (especially, warm currents) commonly affect the occurrence and production of this kelp in those regions. Techniques in propagation of S. japonica in the wild and by cultivation has been developed in both Hokkaido and Primorye. The total annual amount of harvest and season were regulated in fisheries in Sakhalin, though only season of the harvest is regulated in Hokkaido. Harvest and cultivation of kelp in three regions have many similarities.