A single origin of the photosynthetic organelle in different Paulinella lineages

<p>Abstract</p> <p>Background</p> <p>Gaining the ability to photosynthesize was a key event in eukaryotic evolution because algae and plants form the base of the food chain on our planet. The eukaryotic machines of photosynthesis are plastids (e.g., chloroplast in plants) that evolved from cyanobacteria through primary endosymbiosis. Our knowledge of plastid evolution, however, remains limited because the primary endosymbiosis occurred more than a billion years ago. In this context, the thecate "green amoeba" <it>Paulinella chromatophora </it>is remarkable because it very recently (i.e., minimum age of ≈ 60 million years ago) acquired a photosynthetic organelle (termed a "chromatophore"; i.e., plastid) <it>via </it>an independent primary endosymbiosis involving a <it>Prochlorococcus </it>or <it>Synechococcus</it>-like cyanobacterium. All data regarding <it>P. chromatophora </it>stem from a single isolate from Germany (strain M0880/a). Here we brought into culture a novel photosynthetic <it>Paulinella </it>strain (FK01) and generated molecular sequence data from these cells and from four different cell samples, all isolated from freshwater habitats in Japan. Our study had two aims. The first was to compare and contrast cell ultrastructure of the M0880/a and FK01 strains using scanning electron microscopy. The second was to assess the phylogenetic diversity of photosynthetic <it>Paulinella </it>to test the hypothesis they share a vertically inherited plastid that originated in their common ancestor.</p> <p>Results</p> <p>Comparative morphological analyses show that <it>Paulinella </it>FK01 cells are smaller than M0880/a and differ with respect to the number of scales per column. There are more distinctive, multiple fine pores on the external surface of FK01 than in M0880/a. Molecular phylogenetic analyses using multiple gene markers demonstrate these strains are genetically distinct and likely comprise separate species. The well-supported monophyly of the <it>Paulinella chromatophora </it>strains analyzed here using plastid-encoded 16S rRNA suggests strongly that they all share a common photosynthetic ancestor. The strain M0880/a is most closely related to Japanese isolates (Kanazawa-1, -2, and Kaga), whereas FK01 groups closely with a Kawaguchi isolate.</p> <p>Conclusion</p> <p>Our results indicate that <it>Paulinella chromatophora </it>comprises at least two distinct evolutionary lineages and likely encompasses a broader taxonomic diversity than previously thought. The finding of a single plastid origin for both lineages shows these taxa to be valuable models for studying post-endosymbiotic cell and genome evolution.</p

Primer registro de la especie japonesa Grateloupia turuturu (Halymeniaceae, Rhodophyta) en la costa del Pacífico mexicano

Floristic surveys were conducted in November 2008, in which we collected specimens of Grateloupia turuturu, growing attached to different substrata in Ensenada Port, Baja California, Mexico. From this finding, monthly observations were performed until July 2010 to find a possible displacement. Populations with specimens average length of 40 cm were commonly found in the harbor. On the basis of morphological and molecular analyses of plastid rbcL gene sequences, we confirmed the taxonomic identity of G. turuturu. We present the first record of G. turuturu as introduced species in the Mexican Pacific coast. Considering this new finding in Mexico, we conclude that the colonization by this species in the Pacific coast has started, and hence its geographical range of distribution is increasing. Likewise, we found Grateloupia californica, and it is discuss its presences on Baja California coast.Se realizaron muestreos florísticos en noviembre de 2008, en los que se recolectaron ejemplares de Grateloupia turuturu creciendo adheridos a diferentes substratos en el puerto de Ensenada, Baja California, México. A partir de este hallazgo, se realizaron observaciones mensuales hasta julio de 2010 para conocer su posible desplazamiento. Poblaciones con especímenes de longitud promedio de 40 cm se encontraron con alta frecuencia en el puerto. Los análisis morfológicos y moleculares de las secuencias del gen rbcL de plastidios confirman la identidad taxonómica de G. turuturu. Se presenta el primer registro de G. turuturu como especie introducida en la costa del Pacífico mexicano. Considerando este nuevo hallazgo, concluimos que la colonización por esta especie en la costa del Pacífico mexicano ha iniciado y con ello se amplía su rango de distribución geográfica. Así mismo, durante los muestreos se encontró a Grateloupia californica de la cual se discute su presencia en las costas de Baja California

Removal of Rectal Foreign Bodies Using Tenaculum Forceps Under Endoscopic Assistance

The incidence of rectal foreign bodies is increasing by the day, though not as common as that of upper gastrointestinal foreign bodies. Various methods for removal of foreign bodies have been reported. Removal during endoscopy using endoscopic devices is simple and safe, but if the foreign body is too large to be removed by this method, other methods are required. We report two cases of rectal foreign body removal by a relatively simple and inexpensive technique. A 42-year-old man with a vibrator in the rectum was admitted due to inability to remove it by himself and various endoscopic methods failed. Finally, the vibrator was removed successfully by using tenaculum forceps under endoscopic assistance. Similarly, a 59-year-old man with a carrot in the rectum was admitted. The carrot was removed easily by using the same method as that in the previous case. The use of tenaculum forceps under endoscopic guidance may be a useful method for removal of rectal foreign bodies

Effect of High-Temperature Annealing on Ion-Implanted Silicon Solar Cells

P-type and n-type wafers were implanted with phosphorus and boron, respectively, for emitter formation and were annealed subsequently at 950∼1050∘C for 30∼90 min for activation. Boron emitters were activated at 1000∘C or higher, while phosphorus emitters were activated at 950∘C. QSSPC measurements show that the implied Voc of boron emitters increases about 15 mV and the J01 decreases by deep junction annealing even after the activation due to the reduced recombination in the emitter. However, for phosphorus emitters the implied Voc decreases from 622 mV to 560 mV and the J01 increases with deep junction annealing. This is due to the abrupt decrease in the bulk lifetime of the p-type wafer itself from 178 μs to 14 μs. PC1D simulation based on these results shows that, for p-type implanted solar cells, increasing the annealing temperature and time abruptly decreases the efficiency (Δηabs=−1.3%), while, for n-type implanted solar cells, deep junction annealing increases the efficiency and Voc, especially (Δηabs=+0.4%) for backside emitter solar cells

Seaweed diversification driven by Taiwan’s emergence and the Kuroshio Current: insights from the cryptic diversity and phylogeography of Dichotomaria (Galaxauraceae, Rhodophyta)

Ocean currents play a role in both facilitating and impeding connectivity of marine organisms’ populations, serving as key drivers and potential barriers. The emergence of Taiwan around five million years ago (Mya) impacted the Kuroshio Current which later shaped the distribution of marine organisms. In this study, we examined how the Kuroshio Current influenced the distribution and population divergence of the marine red alga Dichotomaria elegans (Galaxauraceae, Nemaliales). Through phylogenetic analysis, species delimitation, and morphological comparison of Taiwanese species, we determined its phylogenetic position relative to other species within the D. marginata complex of the genus Dichotomaria. We uncovered the hidden cryptic diversity within the D. marginata complex in Taiwan and proposed the new combinations D. elegans and D. latifolia based on Galaxaura elegans and G. latifolia. Genetic analysis based on three loci (mitochondrial cox2-3 and cox1, and plastid rbcL) from 32 locations across the Philippines, Taiwan, and Japan revealed three allopatric lineages within D. elegans. The first lineage is restricted to the northern Philippines and southern Taiwan, while the second has a broader latitudinal range along the Kuroshio Current. The third lineage is found in southeast Luzon, Philippines, close to the bifurcation of the North Equatorial Current, near the start of the Kuroshio Current. The divergence of the first two lineages during the mid-Pliocene (~3.7 Mya) coincided with the emergence of Taiwan, with the current dynamics accentuating their separation. The Kuroshio Current exhibited a dual impact on the biogeography of D. elegans: promoting the dispersal of the second lineage towards higher latitudes and preventing the first lineage from moving northward. Principal component analysis showed that habitat conditions and morphologies differed between the two D. elegans lineages. This study provides insights into the cryptic diversity of Dichotomaria in Taiwan, as well as the genetic divergence, biogeographical patterns, and ecological associations of D. elegans, highlighting the interplay of island formation and currents shaping the diversification of seaweeds in the Northwest Pacific Ocean

The secondary prophylactic efficacy of beta-blocker after endoscopic gastric variceal obturation for first acute episode of gastric variceal bleeding

Background/AimsThe most appropriate treatment for acute gastric variceal bleeding (GVB) is currently endoscopic gastric variceal obturation (GVO) using Histoacryl®. However, the secondary prophylactic efficacy of beta-blocker (BB) after GVO for the first acute episode of GVB has not yet been established. The secondary prophylactic efficacy of BB after GVO for the first acute episode of GVB was evaluated in this study.MethodsNinety-three patients at Soonchunhyang University Hospital with acute GVB who received GVO using Histoacryl® were enrolled between June 2001 and March 2010. Among these, 42 patients underwent GVO alone (GVO group) and 51 patients underwent GVO with adjuvant BB therapy (GVO+BB group). This study was intended for patients in whom a desired heart rate was reached. The rates of rebleeding-free survival and overall survival were calculated for the two study groups using Kaplan-Meyer analysis and Cox's proportional-hazards model.ResultsThe follow-up period after the initial eradication of gastric varices was 18.14±25.22 months (mean±SD). During the follow-up period, rebleeding occurred in 10 (23.8%) and 21 (41.2%) GVO and GVO+BB patients, respectively, and 39 patients died [23 (54.8%) in the GVO group and 16 (31.4%) in the GVO+BB group]. The mean rebleeding-free survival time did not differ significantly between the GVO and GVO+BB groups (65.40 and 37.40 months, respectively; P=0.774), whereas the mean overall survival time did differ (52.54 and 72.65 months, respectively; P=0.036).Conclusions Adjuvant BB therapy after GVO using Histoacryl® for the first acute episode of GVB could decrease the mortality rate relative to GVO alone. However, adjuvant BB therapy afforded no benefit for the secondary prevention of rebleeding in GV

Establishment of Efficacy and Safety Assessment of Human Adipose Tissue-Derived Mesenchymal Stem Cells (hATMSCs) in a Nude Rat Femoral Segmental Defect Model

Human adipose tissue-derived mesenchymal stem cell (hATMSC) have emerged as a potentially powerful tool for bone repair, but an appropriate evaluation system has not been established. The purpose of this study was to establish a preclinical assessment system to evaluate the efficacy and safety of cell therapies in a nude rat bone defect model. Segmental defects (5 mm) were created in the femoral diaphyses and transplanted with cell media (control), hydroxyapatite/tricalcium phosphate scaffolds (HA/TCP, Group I), hATMSCs (Group II), or three cell-loading density of hATMSC-loaded HA/TCP (Group III-V). Healing response was evaluated by serial radiography, micro-computed tomography and histology at 16 weeks. To address safety-concerns, we conducted a GLP-compliant toxicity study. Scanning electron microscopy studies showed that hATMSCs filled the pores/surfaces of scaffolds in a cell-loading density-dependent manner. We detected significant increases in bone formation in the hATMSC-loaded HA/TCP groups compared with other groups. The amount of new bone formation increased with increases in loaded cell number. In a toxicity study, no significant hATMSC-related changes were found in body weights, clinical signs, hematological/biochemical values, organ weights, or histopathological findings. In conclusion, hATMSCs loaded on HA/TCP enhance the repair of bone defects and was found to be safe under our preclinical efficacy/safety hybrid assessment system