Fatty acid methyl ester profiles and nutritive values of 20 marine microalgae in Korea

Objecive:To screen the fatty acid(FA) composition of 20 marine microalgae species,including seven Diophyceae,six Bacillariophyeae four Chlorophyceae,two Haptophyceae and one Raphidophyceae species.Methods:Microalgal cells cultured at the Korea Institute of Ocean Science & Technology were harvested during the late exponential growth phase and the FA composition analyzed.Results:The FA composition of microalgae was speciesspecific.For example,seven different species of Dinophyceae were composed primarily of C14:0,C16:0.C18:0.C20:4n-6.C20:5n-3 and C22:6n-3.while C14:0.C16:0,C16:1.C18:0.C20:5n-3 and C22:6n-3 were abundant FAs in six species of Bacillariophyceae.In addition,four Chlurophyceae,two Haptopkyeeae and one Raphidophyceae species all contained a high degree of C16:1 n-7[(9.2R-34.91)%and(34.48-35.04)%].C14:0[(13.34-25.96)%]and[(26.69-Z8.24)%],and C16:0[(5.89-29.15)%]and[(5.70-16.81)%].Several factors contribute to the nutritional value of microalgae.including the polyunsaturated FA content and n-3 to n-6 FA ratio,which could be used to assess the nutritional quality of microalgae.Conclusions:This study is the first comprehensive assessment of the FA composition and nutritional value of microalgae species in South Korea,and identifies the potential utility of FAs as species-specific biomarkers.

Detection of coat protein gene of nervous necrosis virus using loopmediated isothermal amplification

Objective:To establish a novel and highly specific loop-mediated isothermal amplification(LAMP) assay for the identification of nervous necrosis virus(NNV) infection.Methods:A set of synthesized primers was used to match the sequences of a specific region of the nnr gene from the National Center for Biotechnology Information database,not originating from NNV-infected fish,the efficiency and specificity of LAMP were measured dependent on the concentration of DNA polymerase and the reaction temperature and time.In addition,to determine species-specific LAMP primers,cross reactivity testing was applied to the reaction between NVV and other virus families including viral hemorrhagic septicemia virus and marine birnavirus.Results:The optimized LAMP reaction carried out at 64 ℃ for 60 min,and above 4 U Bst DNA polymerase.The sensitivity of LAMP for the detection of nnv was thus about 10 times greater than the sensitivity of polymerase chain reaction.The LAMP assay primers were specific for the detection NNV infection in Epinephelus septemfasciatus.Conclusions:The development of LAMP primers based on genetic information from a public database,not virus-infected samples,may provide a very simple and convenient method to identify viral infection in aquatic organisms.

Phenol content,antioxidant and tyrosinase inhibitory activity of mangrove plants in Micronesia

Objective:To find out and compare the in vitro antioxidant and tyrosinase inhibitory activities of two species of mangrove plants.Methods:Mangrove samples were harvested at the shoreline on the island of Weno,Chuuk State in Micronesia.The phenol content,antioxidant activity(based on DPPH-free radical scavenging)and tyrosinase inhibitory activity in different tissues(leaves,barks and roots)of Rhizophora stylosa(R.stylosa)and Sonneratia alba(S.alba),collected from the island of Weno.Results:Total phenol content ranged from 4.87 to 11.96 mg per g of freeze dried samples.The highest antioxidant activity was observed in R.styiosa bark(85.5%).The highest tyrosinase inhibitory activity was found in S.alba bark.Also,total phenol content and antioxidant activity were higher in methanol extracts than in aqueous extracts.Conclusions:Taken together,the results of this study proved that mangroves can be excellent sources of antioxidant compounds.