scholarly journals The apicoplast: a red alga in human parasites

2011 ◽  
Vol 51 ◽  
pp. 111-125 ◽  
Author(s):  
Boris Striepen
Keyword(s):  
Red Alga ◽  
Obligate Parasites ◽  
Red Algal ◽  
Causative Agents ◽  
Algal Endosymbiont ◽  
And Function ◽  
Metabolic Dependence ◽  
Tremendous Challenge ◽  
Human And Animal Diseases

Surprisingly, some of the world's most dangerous parasites appear to have had a benign photosynthetic past in the ocean. The phylum Apicomplexa includes the causative agents of malaria and a number of additional human and animal diseases. These diseases threaten the life and health of hundreds of millions each year and pose a tremendous challenge to public health. Recent findings suggest that Apicomplexa share their ancestry with diatoms and kelps, and that a key event in their evolution was the acquisition of a red algal endosymbiont. A remnant of this endosymbiont is still present today, albeit reduced to a small chloroplast-like organelle, the apicoplast. In the present chapter, I introduce the remarkably complex biology of this organelle. The apicoplast is bounded by four membranes, and these membranes trace their ancestry to three different organisms. Intriguingly, this divergent ancestry is still reflected in their molecular makeup and function. We also pursue the raison d'être of the apicoplast. Why did Apicomplexa retain a chloroplast when they abandoned photosynthesis for a life as obligate parasites? The answer to this question appears to lie in the profound metabolic dependence of the parasite on its endosymbiont. This dependence may prove to be a liability to the parasite. As humans lack chloroplasts, the apicoplast has become one of the prime targets for the development of parasite-specific drugs.

First reports of the red alga Hypoglossum caloglossoides from the Mediterranean and the Red Sea

2015 ◽  
Vol 58 (4) ◽  
Author(s):  
Razy Hoffman ◽  
Michael J. Wynne
Keyword(s):  
Red Sea ◽  
Algal Species ◽  
Red Alga ◽  
Red Algal ◽  
The Mediterranean

AbstractThe occurrence of the red algal species

New Bioactive Secondary Metabolites from Bornean Red Alga, Laurencia similis (Ceramiales)

2013 ◽  
Vol 8 (3) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Takashi Kamada ◽  
Charles Santhanaraju Vairappan
Keyword(s):  
Antibacterial Activity ◽  
Secondary Metabolites ◽  
Secondary Metabolite ◽  
Red Alga ◽  
Algal Population ◽  
Cytotoxic Effects ◽  
Antibiotic Resistant ◽  
Good Antibacterial Activity ◽  
Bioactive Secondary Metabolites ◽  
Red Algal

A Bornean red algal population of Laurencia simlis Nam et Saito was analyzed for its secondary metabolite composition. Seven compounds were identified: ent -1(10)-aristolen-9β-ol (1), (+)-aristolone (2), axinysone B (3), 9-aristolen-1α-ol (4), 2,3,5,6-tetrabromoindole (5), 1-methyl-2,3,5,6-tetrabromoindole (6), and 1-methyl-2,3,5-tribromoindole (7). Compound 1 was identified as a new optical isomer of 1(10)-aristolen-9β-ol. Compounds 1, 4 and 5 exhibited good antibacterial activity against antibiotic resistant clinical bacteria and cytotoxic effects against selected cancer cell lines.

scholarly journals The amino acid sequence of ferredoxin from the red alga Porphyra umbilicalis

1978 ◽  
Vol 173 (2) ◽  
pp. 459-466 ◽  
Author(s):  
I Takruri ◽  
B G Haslett ◽  
D Boulter ◽  
P W Andrew ◽  
L J Rogers
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Red Alga ◽  
Phenyl Isothiocyanate ◽  
Plant Type ◽  
Considerable Similarity ◽  
Porphyra Umbilicalis ◽  
N Terminus ◽  
Red Algal ◽  
Cnbr Cleavage

The amino acid sequence of the ferrodoxin of Porphyra umbilicalis was determined by the dansyl-phenyl isothiocyanate method, on peptides obtained by tryptic, chymotryptic and thermolytic digestion of the protein or its CNBr-cleavage fragments. The molecule consists of 98 residues, has an unblocked N-terminus and shows considerable similarity with other plant-type ferredoxins. It is the first reported sequence of a red-algal ferredoxin.

scholarly journals Phylogenomics invokes the clade housing Cryptista, Archaeplastida, and Microheliella maris

2021 ◽  
Author(s):  
Euki Yazaki ◽  
Akinori Yabuki ◽  
Ayaka Imaizumi ◽  
Keitaro Kume ◽  
Tetsuo Hashimoto ◽  
...  
Keyword(s):  
Large Scale ◽  
Phylogenetic Signal ◽  
Taxon Sampling ◽  
Secondary Endosymbiosis ◽  
The Novel ◽  
Sister Relationship ◽  
Homologous Genes ◽  
Gene Alignment ◽  
Red Algal ◽  
Algal Endosymbiont

AbstractAs-yet-undescribed branches in the tree of eukaryotes are potentially represented by some of “orphan” protists (unicellular micro-eukaryotes), of which phylogenetic affiliations have not been clarified in previous studies. By clarifying the phylogenetic positions of orphan protists, we may fill the previous gaps in the diversity of eukaryotes and further uncover the novel affiliation between two (or more) major lineages in eukaryotes. Microheliella maris was originally described as a member of the phylum Heliozoa, but a pioneering large-scale phylogenetic analysis failed to place this organism within the previously described species/lineages with confidence. In this study, we analyzed a 319-gene alignment and demonstrated that M. maris represents a basal lineage of one of the major eukaryotic lineages, Cryptista. We here propose a new clade name “Pancryptista” for Cryptista plus M. maris. The 319-gene analyses also indicated that M. maris is a key taxon to recover the monophyly of Archaeplastida and the sister relationship between Archaeplastida and Pancryptista, which is collectively called as “CAM clade” here. Significantly, Cryptophyceae tend to be attracted to Rhodophyta depending on the taxon sampling (ex., in the absence of M. maris and Rhodelphidia) and the particular phylogenetic “signal” most likely hindered the stable recovery of the monophyly of Archaeplastida in previous studies. We hypothesize that many cryptophycean genes (including those in the 319-gene alignment) recombined partially with the homologous genes transferred from the red algal endosymbiont during secondary endosymbiosis and bear a faint phylogenetic affinity to the rhodophytan genes.

scholarly journals Group II intron and repeat-rich red algal mitochondrial genomes demonstrate the dynamic recent history of autocatalytic RNAs

BMC Biology ◽  
2022 ◽  
Vol 20 (1) ◽  
Author(s):  
Dongseok Kim ◽  
JunMo Lee ◽  
Chung Hyun Cho ◽  
Eun Jeung Kim ◽  
Debashish Bhattacharya ◽  
...  
Keyword(s):  
Related Species ◽  
Group Ii Intron ◽  
Red Alga ◽  
Group Ii Introns ◽  
Rapid Sequence ◽  
Two Factors ◽  
Red Algal ◽  
Intergenic Regions ◽  
History Of ◽  
Group Ii

Abstract Background Group II introns are mobile genetic elements that can insert at specific target sequences, however, their origins are often challenging to reconstruct because of rapid sequence decay following invasion and spread into different sites. To advance understanding of group II intron spread, we studied the intron-rich mitochondrial genome (mitogenome) in the unicellular red alga, Porphyridium. Results Analysis of mitogenomes in three closely related species in this genus revealed they were 3–6-fold larger in size (56–132 kbp) than in other red algae, that have genomes of size 21–43 kbp. This discrepancy is explained by two factors, group II intron invasion and expansion of repeated sequences in large intergenic regions. Phylogenetic analysis demonstrates that many mitogenome group II intron families are specific to Porphyridium, whereas others are closely related to sequences in fungi and in the red alga-derived plastids of stramenopiles. Network analysis of intron-encoded proteins (IEPs) shows a clear link between plastid and mitochondrial IEPs in distantly related species, with both groups associated with prokaryotic sequences. Conclusion Our analysis of group II introns in Porphyridium mitogenomes demonstrates the dynamic nature of group II intron evolution, strongly supports the lateral movement of group II introns among diverse eukaryotes, and reveals their ability to proliferate, once integrated in mitochondrial DNA.

Ultrastructure of cell division in the unicellular red alga Flintiella sanguinaria

1986 ◽  
Vol 64 (3) ◽  
pp. 516-524 ◽  
Author(s):  
Joe Scott
Keyword(s):  
Cell Division ◽  
Cell Formation ◽  
Taxonomic Revision ◽  
Red Alga ◽  
Cell Periphery ◽  
Animal Cells ◽  
Porphyridium Purpureum ◽  
Structural Details ◽  
Red Algal ◽  
Reduced Forms

Cell division was examined with the electron microscope in the unicellular red alga Flintiella sanguinaria. Flintiella morphologically resembles Porphyridium purpureum, the only other red algal unicell that has been examined for ultra-structural details of cell division. Both genera are in the order Porphyridiales (Bangiophyceae), an unnatural assemblage of reduced forms in great need of taxonomic revision. Before mitosis, the nucleus migrates to the cell periphery. As in all red algae examined, except Porphyridium, the nucleus-associated organelle is a polar ring. At prometaphase, one or two microtubule-containing cytoplasmic invaginations penetrate the nucleus at each pole. By metaphase an intranuclear spindle is found in association with a typical metaphase chromosomal plate. The nuclear envelope is intact except for a single, large gap at each pole. Perinuclear endoplasmic reticulum is absent. An elongated anaphase interzonal midpiece is formed which breaks down at telophase. The daughter nuclei are widely separated by the chloroplast, which is constricted at the same time as daughter cell formation occurs by a cleavage furrow associated with a finely filamentous region similar to the contractile ring found in many animal cells. Because of pronounced differences in several mitotic features, it is concluded that Flintiella is not closely related to Porphyridium and instead shows closer phylogenetic ties with other macroscopic genera.

Functional characterization of a cellulose synthase, CtCESA1, from the marine red alga Calliarthron tuberculosum (Corallinales)

2021 ◽  
Author(s):  
Jan Xue ◽  
Pallinti Purushotham ◽  
Justin F Acheson ◽  
Ruoya Ho ◽  
Jochen Zimmer ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacterial Species ◽  
Functional Characterization ◽  
Cellulose Synthase ◽  
Red Alga ◽  
Land Plant ◽  
Primary Cell Wall ◽  
Vitro Assay ◽  
Red Algal

Abstract In land plants and algae, cellulose is important for strengthening cell walls and preventing breakage due to physical forces. Though our understanding of cellulose production by cellulose synthase enzymes (CESAs) has seen significant advances for several land plant and bacterial species, functional characterization of this fundamental protein is absent in red algae. Here we identify CESA gene candidates in the calcifying red alga Calliarthron tuberculosum (Ct) using sequence similarity-based approaches and elucidate their phylogenetic relationship with other CESAs from diverse taxa. One gene candidate, CtCESA1, was closely related to other putative red algal CESAs. To test if CtCESA1 encoded a true cellulose synthase, CtCESA1 protein was expressed and purified from insect and yeast expression systems. CtCESA1 showed glucan synthase activity in glucose tracer assays. CtCESA1 activity was relatively low when compared to plant and bacterial CESA activity. In an in vitro assay, a predicted N-terminal starch-binding domain from CtCESA1 bound red algal floridean starch extracts, representing a unique domain in red algal CESAs not present in CESAs from other lineages. When the CtCESA1 gene was introduced into Arabidopsis thaliana cesa mutants, the red algal CtCESA1 partially rescued the growth defects of the primary cell wall cesa6 mutant, but not cesa3 or secondary cell wall cesa7 mutants. A fluorescently tagged CtCESA1 localized to the plasma membrane in the Arabidopsis cesa6 mutant background. This study presents functional evidence validating the sequence annotation of red algal cellulose synthases. The relatively low activity of CtCESA1, partial complementation in Arabidopsis, and presence of unique protein domains suggest that there are likely functional differences between the algal and land plant CESAs.

Ultrastructure of Nucleomorph Division in Species of Cryptophyceae and its Evolutionary Implications

1982 ◽  
Vol 54 (1) ◽  
pp. 311-328
Author(s):  
SUSAN MORRALL ◽  
A. D. GREENWOOD
Keyword(s):  
Nucleic Acids ◽  
Ultrastructural Study ◽  
Nuclear Division ◽  
Mitotic Division ◽  
Red Algal ◽  
Division Process ◽  
Algal Endosymbiont

An ultrastructural study of nucleomorphs in species of Cryptophyceae revealed aspects of division not previously reported, including the formation of a structured fibrous system, which accompanies the ordered alignment, duplication and separation into two groups of the densely staining particles typically characteristic of each nucleomorph. Despite reports indicating the presence of nucleic acids in the nucleomorph, the division process appears to be unlike any known form of nuclear division. However, the possibility exists that the nucleomorph represents the nucleus of a primitive ancestral red algal endosymbiont displaying a form so antique that its nuclear division bears no resemblance to any other known form of mitotic division.

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