Microalgae for economic applications: advantages and perspectives for bioethanol.

Renewable energy has attracted significant interest in recent years as a result of sustainability, environmental impact, and socio-economic considerations. Given existing technological knowledge and based on projections relating to biofuels derived from microalgae, microalgal feedstock is considered to be one of the most important renewable energy sources potentially available for industrial production. Therefore, this review examines microalgal bioethanol technology, which converts biomass from microalgae to fuel, the chemical processes involved, and possible ways of increasing the bioethanol yield, such as abiotic factors and genetic manipulation of fermenting organisms.

Absorption of metals and characterization of chemical elements present in three species of Gracilaria (Gracilariaceae) Greville: a genus of economical importance

Gracilaria Greville is a genus of seaweed that is economically explored by the cosmetic, pharmaceutical and food industries. One of the biggest problems associated with growing Gracilaria is the discharge of heavy metals into the marine environment. The absorption of heavy metals was investigated with the macroalga Gracilaria tenuistipitata Zhang et Xia, cultivated in a medium containing copper (Cu) and cadmium (Cd). In biological samples, EC50 concentrations of 1 ppm for cadmium and 0.95 ppm for copper were used. These concentrations were based on seaweed growth curves obtained over a period of six days in previous studies. ICP-AES was used to determine the amount of metal that seaweeds absorbed during this period. G. tenuistipitata was able to bioaccumulate both metals, about 17 percent of copper and 9 percent of cadmium. Basal natural levels of Cu were found in control seaweeds and in G. tenuistipitata exposed to Cd. In addition, the repertoire of other important chemical elements, as well as their concentrations, was determined for G. tenuistipitata and two other important seaweeds, G. birdiae Plastino & Oliveira and G. domingensis (Kützing) Sonder ex Dickie, collected in natural environments on the Brazilian shore.

Metabolites from algae with economical impact.

In order to survive in a highly competitive environment, freshwater or marine algae have to develop defense strategies that result in a tremendous diversity of compounds from different metabolic pathways. Recent trends in drug research from natural sources have shown that algae are promising organisms to furnish novel biochemically active compounds. The current review describes the main substances biosynthesized by algae with potential economic impact in food science, pharmaceutical industry and public health. Emphasis is given to fatty acids, steroids, carotenoids, polysaccharides, lectins, mycosporine-like amino acids, halogenated compounds, polyketides and toxins.

Sequence diversity and evolution of the malaria vaccine candidate merozoite surface protein-1 (MSP-1) of Plasmodium falciparum.

The merozoite surface protein-1 (MSP-1) of the malaria parasite Plasmodium falciparum is a major blood-stage antigen containing highly polymorphic tripeptide repeats in the domain known as block 2 and several non-repetitive domains that are essentially dimorphic. We have analyzed sequence variation in block 2 repeats and in non-repetitive block 17, as well as other polymorphisms within the MSP-1 gene, in clinical isolates of P. falciparum. Repeat haplotypes were defined as unique combinations of repeat motifs within block 2, whereas block 17 haplotypes were defined as unique combinations of single nucleotide replacements in this domain. A new block 17 haplotype, E-TNG-L, was found in one isolate from Vietnam. MSP-1 alleles, defined as unique combinations of haplotypes in blocks 2 and 17 and other polymorphisms within the molecule, were characterized in 60 isolates from hypoendemic Brazil and 37 isolates from mesoendemic Vietnam. Extensive diversity has been created in block 2 and elsewhere in the molecule, while maintaining significant linkage disequilibrium between polymorphisms across the non-telomeric MSP-1 locus separated by a map distance of more than 4 kb, suggesting that low meiotic recombination rates occur in both parasite populations. These results indicate a role for non-homologous recombination, such as strand-slippage mispairing during mitosis and gene conversion, in creating variation in a malarial antigen under strong diversifying selection.