Diatoms and a variety of other algae evolved by secondary endocytobiosis, i.e. by uptake of a eukaryotic alga into a eukaryotic host cell and the subsequent transformation of the endosymbiont into an organelle. Due to this explicit evolutionary history diatoms possess plastids bound by four membranes. Nucleus encoded plastid preproteins in diatoms have N-terminal bipartite presequences consisti...

Plastids are the characteristic organelles of plant and algae cells and are, like mitochondria, of endosymbiontic origin. They can be traced back to a single cyanobacterial ancestor that was engulfed by a primitive protist about 1.5 billion years ago (Yoon et al., 2004). Higher plants possess different types of plastids, among them undifferentiated proplastids, colorless etioplasts, green photo...

In organisms with complex plastids acquired by secondary endosymbiosis from a photosynthetic eukaryote, the majority of plastid proteins are nuclear-encoded, translated on cytoplasmic ribosomes, and guided across four membranes by a bipartite targeting sequence. In-depth understanding of this vital import process has been impeded by a lack of information about the transit peptide part of this s...

The realization that prokaryotes naturally and frequently disperse genes across steep taxonomic boundaries via lateral gene transfer (LGT) gave wings to the idea that eukaryotes might do the same. Eukaryotes do acquire genes from mitochondria and plastids and they do transfer genes during the process of secondary endosymbiosis, the spread of plastids via eukaryotic algal endosymbionts. From tho...

Apicomplexan parasites commonly contain a unique, non-photosynthetic plastid-like organelle termed the apicoplast. Previous analyses of other plastid-containing organisms suggest that apicoplasts were derived from a red algal ancestor. In this report, we present an extensive phylogenetic study of apicoplast origins using multiple previously reported apicoplast sequences as well as several seque...

Genes encoding enzymes of the tetrapyrrole biosynthetic pathway were searched within Euglena gracilis EST databases and 454 genome reads and their 5' end regions were sequenced when not available. Phylogenetic analyses and protein localization predictions support the hypothesis concerning the presence of two separated tetrapyrrole pathways in E. gracilis. One of these pathways resembles the hem...

Plastids are the characteristic organelles of plant and algae cells and are, like mitochondria, of endosymbiontic origin. They can be traced back to a single cyanobacterial ancestor that was engulfed by a primitive protist about 1.5 billion years ago (Yoon et al., 2004). Higher plants possess different types of plastids, among them undifferentiated proplastids, colorless etioplasts, green photo...

The loss of photosynthetic function should lead to the cessation of expression and finally loss of photosynthetic genes in the new heterotroph. Dinoflagellates are known to have lost their photosynthetic ability several times. Dinoflagellates have also acquired photosynthesis from other organisms, either on a long-term basis or as "kleptoplastids" multiple times. The fate of photosynthetic gene...

The occurrence of RNA in plastids from etiolated and green maize leaves was demonstrated cytochemically, with both the light and the electron microscope. Etiolated leaves were allowed to incorporate tritiated cytidine for several hours and were subsequently fixed in formalin. Radioautographs of leaf sections 2 micro thick showed silver grains over the regions of the cytoplasm containing plastid...