Specific growth rate and mitotic index in dinoflagellate Symbiodinium sp. isolateed from sea anemone Stichodactyla haddoni

The cultivation techniques of dinoflagellates is often problematic due to their sensitivity to hydrodynamic (shear) stress. For this study, sea anemone was collected from the east coast of Hormuz Island. First, we extracted symbiotic dinoflagellate, Symbiodinium sp. from Stichodactylla haddoni using manually homogenization. After transferring to the laboratory, samples were cultured in different mediums of ASP12, ASP8, F2-Gillard and L1, under temperatures of 17±1, 23±1 and 29±1 °C. The amount of light was about 100 µ mol.photon.m-2.s-1. Then, microalgae were cultured again in the selective medium ASP12. Cell counting was performed using a Neubauer chamber every day. Growth and mitotic index were measured during the period of cultivation. Maximum mitotic index, cell numbers and growth rates were observed at 23±1 °C at a rate of 40%, 12×105 cell/ml and 0.086 d-1,respectively. The results showed significant differences between cell numbers and growth rates of Zooxanthellae at three different temperatures (P <0.05). In conclusion, this study showed that environmental factors such as temperature can affect the growth rate of dinoflagellate, Symbiodinium sp

Biotic and Abiotic Factors Affecting the Population Dynamics of Ceratium hirundinella, Peridinium cinctum, and Peridiniopsis elpatiewskyi

The present research was conducted to assess the impact of abiotic and biotic factors on the growth of freshwater dinoflagellates such as Ceratium hirundinella, Peridinium cinctum, and Peridiniopsis elpatiewskyi, which reduce the quality of drinking water in the Zayandeh Rud Reservoir. To this end, 152 algal and zoological samples were collected from the reservoir located in the Central part of Iran in January, April, July, and October 2011. Abiotic factors such as pH, temperature, conductivity, transparency, dissolved oxygen, and nutrient concentration of the water were measured in all study stations. The results showed that the population dynamics of dinoflagellates in the Zayandeh Rud Reservoir was different depending on season, station, and depth. The findings proved that C. hirundinella was one of the dominant autumn planktons in the highest biovolume in the Zayandeh Rud Reservoir. While P. elpatiewskyi was present in the reservoir throughout a year with biovolume peak in summer. Accompanying bloom of P. elpatiewskyi and C. hirundinella, P. cinctum also grew in well-heated summer and autumn waters. It was further found that Ceratium density was positively correlated with sulfate ion concentrations, while the growth of P. cinctum and P. elpatiewskyi were associated, first and foremost, with NO2&minus; and Mn

Effect of nutrients on total lipid content and fatty acids profile of Scenedesmus obliquus

ABSTRACT The effect of nutrients on the total lipid content and fatty acid profile of Scenedesmus obliquus isolated from the south coast of the Caspian Sea was evaluated. The nutritional compositions of the media impacted the growth rate and biomass of S. obliquus that ranged from 0.175 day-1 to 0.209 day-1and 0.92 gr·l-1 to 1.79 gr·l-1, respectively. The alga grew better in the medium which was characterized by higher levels of sodium and trace elements such as Fe, Mn, Mo, and Co and poor in N and P as compared with the other media. The highest level of the total lipid (32%) and the highest values of saturated fatty acids, in particular palmitic acid also were positively correlated with these nutrients. Peaks in polyunsaturated fatty acids (43.7 %), especially α-linolenic acid (28.4%) were related to N and P, but its correlation with K and Mg was more evident. The most important factors correlated with high amount of monounsaturated fatty acids were also N and P, followed by K and Mg to a lesser extent. This study demonstrated that the same algal strain may be a source of different amount of fatty acids, depending on the composition of the culture medium

Relationship between antioxidant traits of Symbiodinium sp. symbiotic dinoflagellate extract under physicochemical factors during different seasons in Persian Gulf and Gulf of Oman

Coral bleaching, loss of symbiotic algae of Symbiodinium sp. or photosynthetic microalgae pigments from their coral host have become commonplace in recent decades due to the rising of sea temperatures and changes in physicochemical factors. It is essential to study the susceptibility of corals to bleaching, the physiology of its symbiotic algae, and its capacity to cope with abiotic stress. Oxidative stress is of particular importance due to the fact that it can be caused by photosynthetic dysfunction drived by temperature and other physicochemical factors. The aim of this study was to compare the effects of physicochemical factors on the photosynthetic performance of Symbiodinium sp. symbiosis with Stichodactyla haddoni in the Persian Gulf and the Gulf of Oman. To determine whether the cultured Symbiodinium sp. has different sensitivities to oxidative stress and whether winter and summer play a role in oxidative stress and coping with it, DPPH test and Freak ion reduction method (FRAP) were used and Physicochemical factors were measured through the HQ40D prototype device. Moreover, air data (wind speed) was obtained from the website www.irimo.ir. Statistical analysis was performed through one-way analysis of variance at the level of 0.05 and heatmap analysis. The results showed that the highest antioxidant capacity was assigned to Symbiodinium sp. extract in Chabahar in winter (IC50:135.768 μgr/ml) and the lowest antioxidant capacity was allocated to Chabahar in summer (IC50:349.090 μgr/ml). Ferric ion reduction of Symbiodinium sp. extracts showed the highest inhibition compared to ascorbic acid at a concentration of 2 mg/ml (0.297) and the lowest inhibition at a concentration of 0.063 mg/ml (0.015) in Chabahar in winter