Identification and characterization of a delta-12 fatty acid desaturase gene from marine microalgae Isochrysis galbana

The cDNA of the delta-12 fatty acid desaturase gene, IgFAD2, was cloned from the marine microalgae Isochrysis galbana, a species capable of producing docosahexaenoic acid. Sequence analysis indicated that the open reading frame measured a length of 1 158 bp and encoded 386 amino acids with a predicted molecular weight of 42.8 kDa and an isoelectric point of 9.2. Computational analysis of the protein sequence of IgFAD2 showed typical features of membrane-bound desaturase such as three conserved histidine boxes along with four membranespanning regions that were universally present among plant desaturases. Quantitative real-time PCR results showed that the abundance of IgFAD2 transcript was significantly upregulated under different environmental stresses including low temperature(15℃), high salinity(salinity of 62 and 93), and nitrogen starvation(220 μmol/L). Heterologous expression indicated that yeast cells transformed with a plasmid construct containing IgFAD2 could convert endogenous oleic acid(18:1^(?9), OA) into linoleic acid(18:2^(?9, 12), LA). These findings confirm that I. galbana IgFAD2 plays important roles in the biosynthetic pathways of unsaturated fatty acids.

Information standardization for typical toxic and harmful algae in China's coastal waters——a case study of Karenia mikimotoi

To assist the researches of toxic and harmful algae and provide government workers with judgment basis for decision-making related events,we established a biological information management system for toxic and harmful algae in China’s of fshore to assist relevant research.In this study,Karenia mikimotoi was studied as a typical toxic and harmful algae species,and the basic biological information and biogeographic distribution information of K.mikimotoi were systematically studied and collected.In the part of basic biological information,the name,toxin,and molecular characteristic sequence of K.mikimotoi were sorted out by literature searching and website browsing.Through experimental means,the relevant information of morphological identifi cation,pigment composition,and lipid composition were obtained.In the part of biogeographic distribution information,this study sorted out the information of K.mikimotoi,analyzed the characteristics of its occurrence,and completed the standardized construction of biogeographic distribution information.Through the collation of basic biological information and biogeographic distribution information of K.mikimotoi,the standardization of related information was completed,which provided template and method reference for information collection of other toxic and harmful algae species,which was benefi cial to the database analysis and design.

Nutrients Extracted from Chicken Manure Accelerate Growth of Microalga <i>Scenedesmus obliquus</i>HTB1

Sustainable development using wastes as resources is a new paradigm. Chicken manure contains rich amounts of nitrogen and phosphorus and has been used as crop fertilizer. However, little is known about whether nutrients of chicken manure are suitable and efficient to support the rapid growth of microalgae. In this study, we explore the possibility of using nutrient extracted from chicken manure to grow microalgae. We used an algal strain Scenedesmus sp. HTB1, which is an oleaginous species with high CO2 tolerance capability. The growth performance of HTB1 on various media amended with nutrient extracted from three different chicken manure sources was monitored and compared to the growth rate of HTB1 grown in the standard medium BG11. Meanwhile, the changes of total nitrogen (N) and phosphorus (P), both organic and inorganic, were measured during the growth period. Culture media enriched with the nutrient extracted from two chicken manure sources outperformed the standard culture medium BG11 in terms of algal biomass production. When cultivated with manure nutrient, HTB1 utilized inorganic N efficiently, but consumed very little organic N during the experimental growth period. However, HTB1 was able to utilize both organic and inorganic phosphorus. We demonstrate that nutrient extracted from chicken manure support rapid growth and high biomass yield in microalgae?Scenedesmus obliquus?HTB1. Therefore chicken manure holds great promise to be used as a cost-effective and efficient fertilizer for large-scale production of microalgae.