Plastid Genome-Based Phylogeny Pinpointed the Origin of the Green-Colored Plastid in the Dinoflagellate Lepidodinium chlorophorum

Unlike many other photosynthetic dinoflagellates, whose plastids contain a characteristic carotenoid peridinin, members of the genus Lepidodinium are the only known dinoflagellate species possessing green alga-derived plastids. However, the precise origin of Lepidodinium plastids has hitherto remained uncertain. In this study, we completely sequenced the plastid genome of Lepidodinium chlorophorum NIES-1868. Our phylogenetic analyses of 52 plastid-encoded proteins unite L. chlorophorum exclusively with a pedinophyte, Pedinomonas minor, indicating that the green-colored plastids in Lepidodinium spp. were derived from an endosymbiotic pedinophyte or a green alga closely related to pedinophytes. Our genome comparison incorporating the origin of the Lepidodinium plastids strongly suggests that the endosymbiont plastid genome acquired by the ancestral Lepidodinium species has lost genes encoding proteins involved in metabolism and biosynthesis, protein/metabolite transport, and plastid division during the endosymbiosis. We further discuss the commonalities and idiosyncrasies in genome evolution between the L. chlorophorum plastid and other plastids acquired through endosymbiosis of eukaryotic photoautotrophs

Prospective randomized study for optimal insulin therapy in type 2 diabetic patients with secondary failure

<p>Abstract</p> <p>Background</p> <p>The large clinical trials proved that Basal-Bolus (BB) insulin therapy was effective in the prevention of diabetic complications and their progression. However, BB therapy needs multiple insulin injections per a day. In this regard, a biphasic insulin analogue needs only twice-daily injections, and is able to correct postprandial hyperglycemia. Therefore it may achieve the blood glucose control as same as that of BB therapy and prevent the diabetic complications including macroangiopathy.</p> <p>Methods</p> <p>In PROBE (Prospective, Randomized, Open, Blinded-Endpoint) design, forty-two type 2 diabetic patients (male: 73.8%, median(inter quartile range) age: 64.5(56.8~71.0)years) with secondary failure of sulfonylurea (SU) were randomly assigned to BB therapy with a thrice-daily insulin aspart and once-daily basal insulin (BB group) or to conventional therapy with a twice-daily biphasic insulin analogue (30 Mix group), and were followed up for 6 months to compare changes in HbA1c, daily glycemic profile, intima-media thickness (IMT) of carotid artery, adiponectin levels, amounts of insulin used, and QOL between the two groups.</p> <p>Results</p> <p>After 6 months, HbA1c was significantly reduced in both groups compared to baseline (30 Mix; 9.3(8.1~11.3) → 7.4(6.9~8.7)%, p < 0.01, vs BB;8.9(7.7~10.0) → 6.9(6.2~7.3)%, p < 0.01), with no significant difference between the groups in percentage change in HbA1c (30 Mix; -14.7(-32.5~-7.5)% vs BB -17.8(-30.1~-11.1)%, p = 0.32). There was a significant decrease in daily glycemic profile at all points except dinner time in both groups compared to baseline. There was a significant increase in the amount of insulin used in the 30 Mix group after treatment compared to baseline (30 Mix;0.30(0.17~0.44) → 0.39(0.31~0.42) IU/kg, p = 0.01). There was no significant difference in IMT, BMI, QOL or adiponectin levels in either group compared to baseline.</p> <p>Conclusion</p> <p>Both BB and 30 mix group produced comparable reductions in HbA1c in type 2 diabetic patients with secondary failure. There was no significant change in IMT as an indicator of early atherosclerotic changes between the two groups. The basal-bolus insulin therapy may not be necessarily needed if the type 2 diabetic patients have become secondary failure.</p> <p>Trial registration</p> <p>Current Controlled Trials number, NCT00348231</p

The cyanobacterium Gloeobacter violaceus PCC 7421 uses bacterial-type phytoene desaturase in carotenoid biosynthesis

AbstractCarotenoid composition and its biosynthetic pathway in the cyanobacterium Gloeobacter violaceus PCC 7421 were investigated. β-Carotene and (2S,2′S)-oscillol 2,2′-di(α-l-fucoside), and echinenone were major and minor carotenoids, respectively. We identified two unique genes for carotenoid biosynthesis using in vivo functional complementation experiments. In Gloeobacter, a bacterial-type phytoene desaturase (CrtI), rather than plant-type desaturases (CrtP and CrtQ), produced lycopene. This is the first demonstration of an oxygenic photosynthetic organism utilizing bacterial-type phytoene desaturase. We also revealed that echinenone synthesis is catalyzed by CrtW rather than CrtO. These findings indicated that Gloeobacter retains ancestral properties of carotenoid biosynthesis

An Enigmatic Stramenopile Sheds Light on Early Evolution in Ochrophyta Plastid Organellogenesis

Ochrophyta is an algal group belonging to the Stramenopiles and comprises diverse lineages of algae which contribute significantly to the oceanic ecosystems as primary producers. However, early evolution of the plastid organelle in Ochrophyta is not fully understood. In this study, we provide a well-supported tree of the Stramenopiles inferred by the large-scale phylogenomic analysis that unveils the eukaryvorous (nonphotosynthetic) protist Actinophrys sol (Actinophryidae) is closely related to Ochrophyta. We used genomic and transcriptomic data generated from A. sol to detect molecular traits of its plastid and we found no evidence of plastid genome and plastid-mediated biosynthesis, consistent with previous ultrastructural studies that did not identify any plastids in Actinophryidae. Moreover, our phylogenetic analyses of particular biosynthetic pathways provide no evidence of a current and past plastid in A. sol. However, we found more than a dozen organellar aminoacyl-tRNA synthases (aaRSs) that are of algal origin. Close relationships between aaRS from A. sol and their ochrophyte homologs document gene transfer of algal genes that happened before the divergence of Actinophryidae and Ochrophyta lineages. We further showed experimentally that organellar aaRSs of A. sol are targeted exclusively to mitochondria, although organellar aaRSs in Ochrophyta are dually targeted to mitochondria and plastids. Together, our findings suggested that the last common ancestor of Actinophryidae and Ochrophyta had not yet completed the establishment of host–plastid partnership as seen in the current Ochrophyta species, but acquired at least certain nuclear-encoded genes for the plastid functions

The secondary electron acceptor of photosystem I in Gloeobacter violaceus PCC 7421 is menaquinone-4 that is synthesized by a unique but unknown pathway

The secondary electron acceptor of photosystem (PS) I in the cyanobacterium Gloeobacter violaceus PCC 7421 was identified as menaquinone-4 (MQ-4) by comparing high performance liquid chromatograms and absorption spectra with an authentic compound. The MQ-4 content was estimated to be two molecules per one molecule of chlorophyll (Chl) a′, a constituent of P700. Comparative genomic analyses showed that six of eight men genes, encoding phylloquinone/MQ biosynthetic enzymes, are missing from the G. violaceus genome. Since G. violaceus clearly synthesizes MQ-4, the combined results indicate that this cyanobacterium must have a novel pathway for the synthesis of 1,4-dihydroxy-2-naphthoic acid

Rappemonads are haptophyte phytoplankton

20年以上謎だった生物の正体が判明 --光合成生物進化解明のカギに--. 京都大学プレスリリース. 2021-03-29.Rapidly accumulating genetic data from environmental sequencing approaches have revealed an extraordinary level of unsuspected diversity within marine phytoplankton, which is responsible for around 50% of global net primary production.However, the phenotypic identity of many of the organisms distinguished by environmental DNA sequences remains unclear. The rappemonads represent a plastid-bearing protistan lineage that to date has only been identified by environmental plastid 16S rRNA sequences.The phenotypic identity of this group, which does not confidently cluster in any known algal clades in 16S rRNA phylogenetic reconstructions, has remained unknown since the first report of environmental sequences over two decades ago. We show that rappemonads are closely related to a haptophyte microalga, Pavlomulina ranunculiformis gen. nov. et sp. nov., and belong to a new haptophyte class, the Rappephyceae. Organellar phylogenomic analyses provide strong evidence for the inclusion of this lineage within the Haptophyta as a sister group to the Prymnesiophyceae. Members of this new class have a cosmopolitan distribution in coastal and oceanic regions. The relative read abundance of Rappephyceae in a large environmental barcoding dataset was comparable to, or greater than, those of major haptophyte species, such as the bloom-forming Gephyrocapsa huxleyi and Prymnesium parvum, and this result indicates that they likely have a significant impact as primary producers. Detailed characterization of Pavlomulina allowed for reconstruction of the ancient evolutionary history of the Haptophyta, a group that is one of the most important components of extant marine phytoplankton communities

Plastid Genome-Based Phylogeny Pinpointed the Origin of the Green-Colored Plastid in the Dinoflagellate Lepidodinium chlorophorum

Unlike many other photosynthetic dinoflagellates, whose plastids contain a characteristic carotenoid peridinin, members of the genus Lepidodinium are the only known dinoflagellate species possessing green alga-derived plastids. However, the precise origin of Lepidodinium plastids has hitherto remained uncertain. In this study, we completely sequenced the plastid genome of Lepidodinium chlorophorum NIES-1868. Our phylogenetic analyses of 52 plastid-encoded proteins unite L. chlorophorum exclusively with a pedinophyte, Pedinomonas minor, indicating that the green-colored plastids in Lepidodinium spp. were derived from an endosymbiotic pedinophyte or a green alga closely related to pedinophytes. Our genome comparison incorporating the origin of the Lepidodinium plastids strongly suggests that the endosymbiont plastid genome acquired by the ancestral Lepidodinium species has lost genes encoding proteins involved in metabolism and biosynthesis, protein/metabolite transport, and plastid division during the endosymbiosis. We further discuss the commonalities and idiosyncrasies in genome evolution between the L. chlorophorum plastid and other plastids acquired through endosymbiosis of eukaryotic photoautotrophs

Identification of 45 New Neutron-Rich Isotopes Produced by In-Flight Fission of a 238U Beam at 345 MeV/nucleon

A search for new isotopes using in-flight fission of a 345 MeV/nucleon 238U beam has been carried out at the RI Beam Factory at the RIKEN Nishina Center. Fission fragments were analyzed and identified by using the superconducting in-flight separator BigRIPS. We observed 45 new neutron-rich isotopes: 71Mn, 73,74Fe, 76Co, 79Ni, 81,82Cu, 84,85Zn, 87Ga, 90Ge, 95Se, 98Br, 101Kr, 103Rb, 106,107Sr, 108,109Y, 111,112Zr, 114,115Nb, 115,116,117Mo, 119,120Tc, 121,122,123,124Ru, 123,124,125,126Rh, 127,128Pd, 133Cd, 138Sn, 140Sb, 143Te, 145I, 148Xe, and 152Ba