The salinity was measured with an inductive salinometer (model MI-150). The water temperature was measured with a mercury thermometer graduated to 0.1 °C. The seaweed samples were analysed in triplicate for their proximate lipid content using the Bligh and Dyer (1959) method. Samples were homogenised with a 1:2 mixture of chloroform and methanol and incubated in the dark overnight. The residues were extracted 2–3 times
with ABT-263 research buy a small amount of chloroform and methanol. The chloroform layer was removed with a separating funnel and then vaporised in an evaporator. The lipid content was calculated by weighing the residues and was expressed as a percentage of dry weight. The fatty acids were converted to methyl esters using the method of Christie (1998). The samples were esterified in 1% sulphuric acid in absolute methanol and extracted with hexane to separate the layers. The hexane layer was washed with water containing potassium bicarbonate and dried over anhydrous sodium sulphate. The solvent was evaporated using a rotary evaporator. The fatty acid methyl esters (FAMEs) were analysed on a Shimadzu gas-liquid chromatographer equipped with a flame ionisation detector with a packing column with Hp-5 material. The carrier gas was nitrogen, and the short speed was 5 mm/min. For the identification and quantification
of FAMEs, their retention times were compared with standards. The values are Ruxolitinib nmr expressed as a percentage of the total fatty acids mixture. The variation in fatty acid composition between the species during different seasons was evaluated using principal component analysis (PCA) (SPSS IBM version 20) with the mean of three individual samples as the variables. Three principal component analyses
(PCAs) were performed Liothyronine Sodium separately on the total, saturated and unsaturated fatty acids. The outcome was plotted in two dimensions (PCA1, PCA2). The score loading was analysed and identified in the bi-plot of PCA1 versus PCA2. The seawater parameters, such as pH, salinity and temperature, showed limited variations during the different seasons (Table 1). The pH value varied between a maximum of 8.11 during spring and a minimum of 7.60 during summer, whereas the pH value during autumn was in between (7.78). The average values of water salinity decreased in the order of autumn (32.15 g/L), spring (36.21 g/L) and summer (38.32 g/L). The seasonal temperature variations followed the climate conditions. There was significant variation between the seasons, with the highest values during the summer (29.30 °C). Furthermore, the lowest values fluctuated between 21.50 °C and 20.90 °C in the autumn and spring, respectively. The seasonal variations in the total lipid content based on the dry weight of J. rubens are shown in Table 2. The highest lipid content was 2.51% in the spring, followed by 2.42% in the summer, and the lowest value was 1.56% in autumn.