Concentration-dependent recovery of growth rate was seen after 24 h for cultures resupplied 3-MA nmr with Si in stationary phase but not in senescence. However, resupply of Si at 100 μM to stationary phase cultures alone increased protease
activity to nearly the levels seen in senescence. Differences in the responses to Si resupply suggest that the ability and time to recover from Si depletion depend not only on the growth phase but also on the concentration resupplied. “
“Microalgae constitute an interesting novel study area for characterizing new esterases, and so we decided to isolate a complete cDNA encoding a new putative microalgal esterase from the haptophyte Isochrysis galbana Parke. Rapid amplifications of both the 5′ and 3′ cDNA ends (RACE) were performed with specific primers, designed using an incomplete candidate gene from the I. galbana expressed sequence tag (EST) database. The full-length cDNA obtained was designated
IgEst1. The coding sequence was 828 bp long, and the deduced amino acid sequence revealed a polypeptide of 275 amino acids with a predicted signal peptide of 23 residues in the N-terminal region. The following 252 amino acids formed, after in silico analysis, a mature protein with a molecular mass of ∼26.92 kDa and had a theoretical pI of 5.87. Alignment analyses revealed slight but significant identity and similarity with carboxylesterases, phospholipases, and lysophospholipases from various organisms including fungi, plants, and Bafilomycin A1 price animals. The new sequence IgEst1 enclosed the catalytic triad Ser/Asp/His and the consensus pentapeptide Gly-X-Ser-X-Gly, two highly conserved patterns found in serine hydrolases. Phylogenetic analyses established a close relationship with putative esterases identified in microalgae genomes. “
“Molecular outcomes led us to report the first selleck occurrence of the invasive alien species Gracilaria vermiculophylla (Ohmi) Papenf. in the Mediterranean Sea. This species was recorded for the first time in the Po Delta lagoons in May and October 2008, probably introduced by
the importation of the Manila clam Tapes philippinarum. At present, G. vermiculophylla is spread only near some clam-farming areas, but its diffusion is expected to increase with the colonization of other lagoons where aquaculture is spread, as already observed for other alien species such as Agardhiella subulata and Solieria filiformis. The present study supplies further information on the morphology of this species, the ecological characteristics of the colonized areas, and the most probable introduction vector, confirming that the species spreading occurs in eutrophic and turbid coastal systems. “
“Neustonic organisms inhabit the sea surface microlayer (SML) and have important roles in marine ecosystem functioning. Here, we use high-throughput 18S rRNA gene sequencing to characterize protist and fungal diversity in the SML at a coastal time-series station and compare with underlying plankton assemblages.