295 research outputs found
Origin of nanosized diamonds in interstellar space and low-pressure-temperature Earth rocks
No full textNanosized diamond particles in the interstellar space and in the Earth rocks related with water presence. In the paper proposed the model of the nanosized diamond particle formation from oxidized water-carbon dioxide gaseous mixtures
Metastable Nanosized Diamond Formation from Fluid Systems
No full textThe model of nanosized diamond particles formation at metastable P-T parameters from fluid is presented. It explains the specific of CVD diamond synthesis gases mixtures and hydrothermal growth of diamond at low P-T parameters as well as it explains the geneses of metamorphic and magmatic nano- and microdiamond in the shallow depth Earth rocks and the genesis of interstellar nanodiamond formations in the space
Euprymna parva Sanchez & Jolly & Reid & Sugimoto & Azama & Marlétaz & Simakov & Rokhsar 2019, comb. nov.
No full textEuprymna parva (Sasaki, 1913), comb. nov. (Figure 1c left, Table 1, Supplementary Figs. 1, 2c, d, Supplementary Table 2). Sepiola parva Sasaki, 1913: 252, Fig. 4. — Sasaki, 1929: 136–137 Pl. XV, Figs. 4 and 5, text Fig. 80; Takayama and Okutani, 1992: 203–214, fig, 2, Figs. 4–6. — Okutani, 1995: 45, fig. 43. Reid and Norman, 1998: 717. — Reid and Jereb, 2005: 165–166, fig. 239. Inioteuthis parva Sasaki, 1914: 595, pl. 11 Figs. 9 and 10. Type locality: Japan, Tokyo Bay. Material examined. 3 ♂ (8.5–10.7 mm ML), 3 ♀ (7.0–8.0 mm ML), East China Sea, Okinawa, Diamond Beach in Seragaki, 26.51N, 127.88E, <2 m, 15 June 2016, coll. J. Jolly, G. Sanchez, A. Masunaga & K. Asada (AM C.574777, Hap 3, and GenBank accession number: LC417215). Remarks. The correct generic placement of this taxon has been equivocal since it was first described. It was first placed in Sepiola, transferred to Inioteuthis Sasaki, 1914, then later retained in the genus Sepiola. Sasaki does not explain why parva was placed in Sepiola in his 1929 treatise, nor why it was referred to Inioteuthis in his 1914 work. Clearly, however, the features noted by Sasaki, 6 (2019) 2:465 | https://doi.org/10.1038/s42003-019-0661-6 | www.nature.com/commsbio “the nipple-like protruberance” near the base of the hectocotylus and the “peculiar and unstalked cylindrical suckers” (Sasaki48: 137) are characteristic of Euprymna. Mature males have two rows of suckers on their arms, in contrast to the four rows typically (but not always) found among Euprymna. This has, no doubt, resulted in its misplacement in the genus Sepiola, that has continued largely without question until now. However, two rows of arm suckers are also found in E. pardalota and E. phenax. The inclusion of the E. pardalota COI sequence in our analyses (Fig. 2) confirms its position, and that of “ Sepiola ” parva in the monophyletic genus Euprymna. Optic lobe transcriptome data (Fig. 3) clearly places S. parva in the monophyletic Euprymna clade, and the pairwise synonymous substitution rate (Ks) between clades (Supplementary Fig. 1) highlights the disjunction between Euprymna and Sepiola, providing strong support for their distinct generic status. The genetic distance data fully supports the placement of S. parva in the genus Euprymna and this evidence now permits a more robust definition of the genus based on morphological characters. The hectocotylus (dorsal left arm) of Euprymna is unique among the Sepiolinae. In all genera but Euprymna, the hectocotylus is clearly tripartite, with a morphologically distinct basal part, copulatory apparatus, and distal part49,50. In contrast, in Euprymna, the hectocotylized arm has a bipartite form, with a proximal portion and a distal modified part. In Euprymna there is no distinct copulatory apparatus, instead the pedicels of the ventral suckers in the third to fourth proximal rows are modified to form 1–2 papillae in most species, sometimes bearing a vestigial sucker, whereas in all other genera the sucker pedicels forming the copulatory apparatus are more conspicuously modified (mostly horn- or hook-like). More importantly, the distal-most portion of the Euprymna hectocotylus bears deeply modified sucker-stalk elements: the stalks are columnar, i.e., thickened and lengthened, and appressed to each other to form palisades, and the sucker proper is reduced to a small opening surrounded by a chitinous rim, often covered by a fleshy cap and embedded in the columnar pedicel. On the contrary, in all other genera, the hectocotylus distal suckers are normal (in some cases some of them may be enlarged and/or their stalks slightly c Male arm crown, dorsal view, holotype 14.9 mm ML (NSMT Mo 85885), scale bar 5 mm. d Female right side (of animal) arm crown, oral view, paratype, 15.3 mm ML (NSMT Mo 85893), scale bar 2 mm. c, d Numbers 1 – 4 indicate Arms 1 – 4. e SEM Arm 4 sucker rim, paratype female, 19.5 mm ML (NSMT Mo 85889), scale bar 20 µm. f SEM enlargement of sucker rim shown in (d), scale bar 10 µm. lengthened) (Bello, submitted). The very simple copulatory apparatus of Euprymna is considered a plesiomorphic character state 51 in the Sepiolinae, placing this genus in a basal position within the subfamily36,52.Published as part of Sanchez, Gustavo, Jolly, Jeffrey, Reid, Amanda, Sugimoto, Chikatoshi, Azama, Chika, Marlétaz, Ferdinand, Simakov, Oleg & Rokhsar, Daniel S., 2019, New bobtail squid (Sepiolidae: Sepiolinae) from the Ryukyu islands revealed by molecular and morphological analysis, pp. 1-15 in Communications Biology 2 (465) on pages 6-7, DOI: 10.1038/s42003-019-0661-6, http://zenodo.org/record/372301
The survey and reference assisted assembly of the Octopus vulgaris genome
No full textThe common octopus, Octopus vulgaris, is an active marine predator known for the richness and
plasticity of its behavioral repertoire, and remarkable learning and memory capabilities. Octopus
and other coleoid cephalopods, cuttlefish and squid, possess the largest nervous system among
invertebrates, both for cell counts and body to brain size. O. vulgaris has been at the center of a longtradition
of research into diverse aspects of its biology. To leverage research in this iconic species, we
generated 270 Gb of genomic sequencing data, complementing those available for the only other
sequenced congeneric octopus, Octopus bimaculoides. We show that both genomes are similar in size,
but display different levels of heterozygosity and repeats. Our data give a first quantitative glimpse into
the rate of coding and non-coding regions and support the view that hundreds of novel genes may have
arisen independently despite the close phylogenetic distance. We furthermore describe a referenceguided
assembly and an open genomic resource (CephRes-gdatabase), opening new avenues in the
study of genomic novelties in cephalopods and their biology.sponsorship: We are recognizing the contribution of Drs A. Cole (currently at University of Vienna), N. Tublitz (Oregon University), and C. Di Cristo (University of Sannio and CephRes) for their generous support at an earlier stage of this project. The contribution of the State Key Laboratory of Agricultural Genomics (grant No. 2011DQ782025) to GEM is also appreciated. EAR and OS are supported by a grant from the Austrian Science Fund (FWF): P30686-B29. We thank the COST Action (FA1301) that facilitated the networking initiative underlying this study. Genome browsers are integrated in the CephRes databases-website platform (http://www.cephalopodresearch.org/ceph_gdatab/) based on a bilateral agreement with University of Vienna. This study was supported by BGIShenzhen and by the Association for Cephalopod Research 'CephRes' a no-profit organization. (State Key Laboratory of Agricultural Genomics|2011DQ782025, Austrian Science Fund (FWF)|P30686-B29, COST Action|FA1301, BGIShenzhen, Association for Cephalopod Research 'CephRes' a no-profit organization, Austrian Science Fund (FWF)|P30686)status: Published onlin
Carbon Supported Metal Carbide Catalysts for the Reduction of Carbon Dioxide
No full textDevelopment of active and selective catalysts for the conversion of CO2 into valuable products is a promising strategy for reducing the environmental impact of CO2 released from the use of fossil fuels. The manufacture of these catalysts should also consider the use of waste materials and reduction of chemicals needed to decrease energy and resource consumption while being economically feasible.
The aim of this research was to prepare a molybdenum-carbide catalyst from petroleum coke (petcoke), an abundant waste material from oil refining, with comparable activity and selectivity to other catalysts studied for the reduction of CO2 by H2. The process of converting petcoke into a catalyst involved increasing its porosity and carburizing added Mo using microwaves or electrical heating, focused on eliminating the need for methane and/or hydrogen for its preparation. Due to pyrophoricity risks, a multiple-test rig was built to study the catalysts preventing their exposure to air or passivation gases. The petcoke-based carbon prepared had higher surface areas and pore volumes (~2000 m2/g and > 1 cm3/g) than other commercial carbons (1000-700 m2/g and ~0.5 cm3/g) which enhanced the catalytic performance towards CO2 reduction. Microwave-assisted synthesis reduced the carbide preparation time from 15 h to 8 min. However, the resulting samples showed low CO2 conversion between 1.6-1.2 %. The catalysts prepared using a furnace showed a maximum CO2 conversion of 5.2 % and selectivity towards CO above 95.8 % after 24 h of reaction comparable to that previously reported for Pt based catalysts. Further investigations evaluated the improvement of the catalyst by re-using the petcoke activation chemical as a promoter. Alkali from petcoke activation with KOH moderately improved CO selectivity (97.4 % to 99.5 %) and stability (deactivation from 34 % to 26%) but decreased CO2 conversion by 2 %. Probable site blockage at high loadings of potassium (~5 wt%) indicate that further washing is needed to decrease the potassium concentration and maximize the promotion effect.
The findings from this thesis provided insights on the preparation methods of Mo2C catalysts and alternative technologies for CO2 capture and re-utilization that is becoming a major cost in the energy sector
Reverse Microemulsion-Synthesized High-Surface-Area Cu/γ-Al<sub>2</sub>O<sub>3</sub> Catalyst for CO<sub>2</sub> Conversion via Reverse Water Gas Shift
No full textReverse
microemulsion method was implemented to synthesize a CuO/γ-Al2O3 catalyst (18 wt % Cu) with a specific surface
area (SSA) of 328 m2/g (after calcination at 400 °C).
Catalytic performance was evaluated in the range of temperatures and
space velocities (300–600 °C and 10,000–200,000
mL/(g h)). The catalyst was 100% selective to CO generation while
attaining a nearly equilibrium CO2 conversion at 500 °C
(ca. 50% at 10,000 mL/(g h) and H2/CO2 = 4).
Despite the initial reduction of surface area under the reaction conditions,
the reduced Cu/γ-Al2O3 catalyst demonstrated
a stable performance for 80 h on stream, attaining a nearly equilibrium
CO2 conversion at 600 °C (ca. 60% at 60,000 mL/(g
h) and H2/CO2 = 4). The selectivity to CO generation
remained complete during the stability test, and no significant carbon
deposition was detected
Mechanism and function of drosophila capa GPCR: a desiccation stress-responsive receptor with functional homology to human neuromedinU receptor
No full textThe capa peptide receptor, capaR (CG14575), is a G-protein coupled receptor (GPCR) for the D. melanogaster capa neuropeptides, Drm-capa-1 and -2 (capa-1 and -2). To date, the capa peptide family constitutes the only known nitridergic peptides in insects, so the mechanisms and physiological function of ligand-receptor signalling of this peptide family are of interest. Capa peptide induces calcium signaling via capaR with EC50 values for capa-1 = 3.06 nM and capa-2 = 4.32 nM. capaR undergoes rapid desensitization, with internalization via a b-arrestin-2 mediated mechanism but is rapidly re-sensitized in the absence of capa-1. Drosophila capa peptides have a C-terminal -FPRXamide motif and insect-PRXamide peptides are evolutionarily related to vertebrate peptide neuromedinU (NMU). Potential agonist effects of human NMU-25 and the insect -PRLamides [Drosophila pyrokinins Drm-PK-1 (capa-3), Drm-PK-2 and hugin-gamma [hugg]] against capaR were investigated. NMU-25, but not hugg nor Drm-PK-2, increases intracellular calcium ([Ca2+]i) levels via capaR. In vivo, NMU-25 increases [Ca2+]i and fluid transport by the Drosophila Malpighian (renal) tubule. Ectopic expression of human NMU receptor 2 in tubules of transgenic flies results in increased [Ca2+]i and fluid transport. Finally, anti-porcine NMU-8 staining of larval CNS shows that the most highly immunoreactive cells are capa-producing neurons. These structural and functional data suggest that vertebrate NMU is a putative functional homolog of Drm-capa-1 and -2. capaR is almost exclusively expressed in tubule principal cells; cell-specific targeted capaR RNAi significantly reduces capa-1 stimulated [Ca2+]i and fluid transport. Adult capaR RNAi transgenic flies also display resistance to desiccation. Thus, capaR acts in the key fluid-transporting tissue to regulate responses to desiccation stress in the fly
The First Myriapod Genome Sequence Reveals Conservative Arthropod Gene Content and Genome Organisation in the Centipede Strigamia maritima
No full textMyriapods (e.g., centipedes and millipedes) display a simple homonomous body plan relative to other arthropods. All members of the class are terrestrial, but they attained terrestriality independently of insects. Myriapoda is the only arthropod class not represented by a sequenced genome. We present an analysis of the genome of the centipede Strigamia maritima. It retains a compact genome that has undergone less gene loss and shuffling than previously sequenced arthropods, and many orthologues of genes conserved from the bilaterian ancestor that have been lost in insects. Our analysis locates many genes in conserved macro-synteny contexts, and many small-scale examples of gene clustering. We describe several examples where S. maritima shows different solutions from insects to similar problems. The insect olfactory receptor gene family is absent from S. maritima, and olfaction in air is likely effected by expansion of other receptor gene families. For some genes S. maritima has evolved paralogues to generate coding sequence diversity, where insects use alternate splicing. This is most striking for the Dscam gene, which in Drosophila generates more than 100,000 alternate splice forms, but in S. maritima is encoded by over 100 paralogues. We see an intriguing linkage between the absence of any known photosensory proteins in a blind organism and the additional absence of canonical circadian clock genes. The phylogenetic position of myriapods allows us to identify where in arthropod phylogeny several particular molecular mechanisms and traits emerged. For example, we conclude that juvenile hormone signalling evolved with the emergence of the exoskeleton in the arthropods and that RR-1 containing cuticle proteins evolved in the lineage leading to Mandibulata. We also identify when various gene expansions and losses occurred. The genome of S. maritima offers us a unique glimpse into the ancestral arthropod genome, while also displaying many adaptations to its specific life history.Version of Recor
The Nereid on the rise: Platynereis as a model system
No full text: The Nereid Platynereis dumerilii (Audouin and Milne Edwards (Annales des Sciences Naturelles 1:195-269, 1833) is a marine annelid that belongs to the Nereididae, a family of errant polychaete worms. The Nereid shows a pelago-benthic life cycle: as a general characteristic for the superphylum of Lophotrochozoa/Spiralia, it has spirally cleaving embryos developing into swimming trochophore larvae. The larvae then metamorphose into benthic worms living in self-spun tubes on macroalgae. Platynereis is used as a model for genetics, regeneration, reproduction biology, development, evolution, chronobiology, neurobiology, ecology, ecotoxicology, and most recently also for connectomics and single-cell genomics. Research on the Nereid started with studies on eye development and spiralian embryogenesis in the nineteenth and early twentieth centuries. Transitioning into the molecular era, Platynereis research focused on posterior growth and regeneration, neuroendocrinology, circadian and lunar cycles, fertilization, and oocyte maturation. Other work covered segmentation, photoreceptors and other sensory cells, nephridia, and population dynamics. Most recently, the unique advantages of the Nereid young worm for whole-body volume electron microscopy and single-cell sequencing became apparent, enabling the tracing of all neurons in its rope-ladder-like central nervous system, and the construction of multimodal cellular atlases. Here, we provide an overview of current topics and methodologies for P. dumerilii, with the aim of stimulating further interest into our unique model and expanding the active and vibrant Platynereis community
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