Claudio Slamovits
Author's posts
Nov 08
The pre-endosymbiont hypothesis: a new perspective on the origin and evolution of mitochondria.
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The pre-endosymbiont hypothesis: a new perspective on the origin and evolution of mitochondria.
Cold Spring Harb Perspect Biol. 2014 Mar;6(3)
Authors: Gray MW
Abstract
Mitochondrial DNA (mtDNA) is unquestionably the remnant of an α-proteobacterial genome, yet only ~10%-20% of mitochondrial proteins are demonstrably α-proteobacterial in origin (the “α-proteobacterial component,” or APC). The evolutionary ancestry of the non-α-proteobacterial component (NPC) is obscure and not adequately accounted for in current models of mitochondrial origin. I propose that in the host cell that accommodated an α-proteobacterial endosymbiont, much of the NPC was already present, in the form of a membrane-bound metabolic organelle (the premitochondrion) that compartmentalized many of the non-energy-generating functions of the contemporary mitochondrion. I suggest that this organelle also possessed a protein import system and various ion and small-molecule transporters. In such a scenario, an α-proteobacterial endosymbiont could have been converted relatively directly and rapidly into an energy-generating organelle that incorporated the extant metabolic functions of the premitochondrion. This model (the “pre-endosymbiont hypothesis”) effectively represents a synthesis of previous, contending mitochondrial origin hypotheses, with the bulk of the mitochondrial proteome (much of the NPC) having an endogenous origin and the minority component (the APC) having a xenogenous origin.
PMID: 24591518 [PubMed – indexed for MEDLINE]
Nov 08
CLOCKS IN ALGAE.
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CLOCKS IN ALGAE.
Biochemistry. 2014 Nov 7;
Authors: Noordally ZB, Millar A
Abstract
As major contributors to global oxygen levels and producers of fatty acids, carotenoid, sterols an…
Nov 06
Getting "function" right.
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Getting “function” right.
Proc Natl Acad Sci U S A. 2014 Aug 19;111(33):E3365
Authors: Brunet TD, Doolittle WF
PMID: 25107292 [PubMed – indexed for MEDLINE]
Oct 31
Rhodoluna lacicola gen. nov., sp. nov., a planktonic freshwater bacterium with stream-lined genome.
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Rhodoluna lacicola gen. nov., sp. nov., a planktonic freshwater bacterium with stream-lined genome.
Int J Syst Evol Microbiol. 2014 Sep;64(Pt 9):3254-63
Authors: Hahn MW, Schmidt J, Taipale SJ, Doolittle WF, Koll U
Abstract
A pure culture of an actinobacterium previously described as ‘Candidatus Rhodoluna lacicola’ strain MWH-Ta8 was established and deposited in two public culture collections. Strain MWH-Ta8(T) represents a free-living planktonic freshwater bacterium obtained from hypertrophic Meiliang Bay, Lake Taihu, PR China. The strain was characterized by phylogenetic and taxonomic investigations, as well as by determination of its complete genome sequence. Strain MWH-Ta8(T) is noticeable due to its unusually low values of cell size (0.05 µm(3)), genome size (1.43 Mbp), and DNA G+C content (51.5 mol%). Phylogenetic analyses based on 16S rRNA gene and RpoB sequences suggested that strain MWH-Ta8(T) is affiliated with the family Microbacteriaceae with Pontimonas salivibrio being its closest relative among the currently described species within this family. Strain MWH-Ta8(T) and the type strain of Pontimonas salivibrio shared a 16S rRNA gene sequence similarity of 94.3 %. The cell-wall peptidoglycan of strain MWH-Ta8(T) was of type B2β (B10), containing 2,4-diaminobutyric acid as the diamino acid. The predominant cellular fatty acids were anteiso-C15 : 0 (36.5 %), iso-C16 : 0 (16.5 %), iso-C15 : 0 (15.6 %) and iso-C14 : 0 (8.9 %), and the major (>10 %) menaquinones were MK-11 and MK-12. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and two unknown glycolipids. The combined phylogenetic, phenotypic and chemotaxonomic data clearly suggest that strain MWH-Ta8(T) represents a novel species of a new genus in the family Microbacteriaceae, for which the name Rhodoluna lacicola gen. nov., sp. nov. is proposed. The type strain of the type species is MWH-Ta8(T) ( = DSM 23834(T) = LMG 26932(T)).
PMID: 24984700 [PubMed – indexed for MEDLINE]
Oct 29
A phylogenomic view of ecological specialization in the Lachnospiraceae, a family of digestive tract-associated bacteria.
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A phylogenomic view of ecological specialization in the Lachnospiraceae, a family of digestive tract-associated bacteria.
Genome Biol Evol. 2014 Mar;6(3):703-13
Authors: Meehan CJ, Beiko RG
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Oct 29
Microsatellite abundance across the Anthozoa and Hydrozoa in the phylum Cnidaria.
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Microsatellite abundance across the Anthozoa and Hydrozoa in the phylum Cnidaria.
BMC Genomics. 2014 Oct 27;15(1):939
Authors: Ruiz-Ramos DV, Baums IB
Abstract
BACKGROUND: Microsate…
Oct 25
Unfolding the secrets of coral-algal symbiosis.
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Unfolding the secrets of coral-algal symbiosis.
ISME J. 2014 Oct 24;
Authors: Rosic N, Ling EY, Chan CK, Lee HC, Kaniewska P, Edwards D, Dove S, Hoegh-Guldberg O
Abstract
Dinoflagellates from the genus Symbiodinium form a mutualistic symbiotic relationship with reef-building corals. Here we applied massively parallel Illumina sequencing to assess genetic similarity and diversity among four phylogenetically diverse dinoflagellate clades (A, B, C and D) that are commonly associated with corals. We obtained more than 30 000 predicted genes for each Symbiodinium clade, with a majority of the aligned transcripts corresponding to sequence data sets of symbiotic dinoflagellates and <2% of sequences having bacterial or other foreign origin. We report 1053 genes, orthologous among four Symbiodinium clades, that share a high level of sequence identity to known proteins from the SwissProt (SP) database. Approximately 80% of the transcripts aligning to the 1053 SP genes were unique to Symbiodinium species and did not align to other dinoflagellates and unrelated eukaryotic transcriptomes/genomes. Six pathways were common to all four Symbiodinium clades including the phosphatidylinositol signaling system and inositol phosphate metabolism pathways. The list of Symbiodinium transcripts common to all four clades included conserved genes such as heat shock proteins (Hsp70 and Hsp90), calmodulin, actin and tubulin, several ribosomal, photosynthetic and cytochrome genes and chloroplast-based heme-containing cytochrome P450, involved in the biosynthesis of xanthophylls. Antioxidant genes, which are important in stress responses, were also preserved, as were a number of calcium-dependent and calcium/calmodulin-dependent protein kinases that may play a role in the establishment of symbiosis. Our findings disclose new knowledge about the genetic uniqueness of symbiotic dinoflagellates and provide a list of homologous genes important for the foundation of coral-algal symbiosis.The ISME Journal advance online publication, 24 October 2014; doi:10.1038/ismej.2014.182.
PMID: 25343511 [PubMed – as supplied by publisher]
Oct 22
Separate Introns Gained within Short and Long Soluble Peridinin-Chlorophyll a-Protein Genes during Radiation of Symbiodinium (Dinophyceae) Clade A and B Lineages.
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Separate Introns Gained within Short and Long Soluble Peridinin-Chlorophyll a-Protein Genes during Radiation of Symbiodinium (Dinophyceae) Clade A and B Lineages.
PLoS One. 2014;9(10):e110608
Author…
Oct 18
Survey of the parasite Toxoplasma gondii in human consumed ovine meat in Tunis City.
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Survey of the parasite Toxoplasma gondii in human consumed ovine meat in Tunis City.
PLoS One. 2014;9(1):e85044
Authors: Boughattas S, Ayari K, Sa T, Aoun K, Bouratbine A
Abstract
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Oct 17
Reduced nuclear genomes maintain high gene transcription levels.
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Reduced nuclear genomes maintain high gene transcription levels.
Mol Biol Evol. 2014 Mar;31(3):625-35
Authors: Tanifuji G, Onodera NT, Moore CE, Archibald JM
Abstract
Reductive geno…