Nutrient limitation is the main regulatory factor for carotenoid accumulation and for Psy and Pds steady state transcript levels in Dunaliella salina (Chlorophyta) exposed to high light and salt stress.

Dunaliella salina (Dunal) Teodoresco (1905) is a green unicellular alga able to withstand severe salt, light, and nutrient stress, adaptations necessary to grow in harsh environments such as salt ponds. In response to such growth conditions, this microalga accumulates high amounts of beta-carotene in its single chloroplast. In this study, we show that carotenoid accumulation is consistently inhibited in cells grown in nutrient-supplemented media and exposed either to high-light or medium-low-light conditions.

Molecular cloning of the Matrix Gla Protein gene from Xenopus laevis. Functional analysis of the promoter identifies a calcium sensitive region required for basal activity.

To analyze the regulation of Matrix Gla Protein (MGP) gene expression in Xenopus laevis, we cloned the xMGP gene and its 5' region, determined their molecular organization, and characterized the transcriptional properties of the core promoter. The Xenopus MGP (xMGP) gene is organized into five exons, one more as its mammalian counterparts. The first two exons in the Xenopus gene encode the DNA sequence that corresponds to the first exon in mammals whereas the last three exons show homologous organization in the Xenopus MGP gene and in the mammalian orthologs.