Structural, morphological and optical properties of chromium oxide nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Babukutty, Blessy; Parakkal, Fasalurahman; Nair, Swapna S., E-mail: swapna.s.nair@gmail.com

2015-06-24

Chromium oxide nanoparticles are synthesized by reduction route from chloride precursors with surfactant, trioctylphosphine oxide (TOPO). Structural and morphological characterization are analyzed using X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Transmission Electron micrographs show that the average grain size lies in the range 5nm to 10nm. Optical characterization has been done by UV-VIS spectrophotometer. Distinct optical absorptions of Cr{sup 3+} ions show hinting towards the presence of Cr{sub 2}O{sub 3}. Presence of oxygen is also confirmed from Electron Energy Loss Spectroscopy (EELS) studies.

Electric field induced microstructures in thin films on physicochemically heterogeneous and patterned substrates.

PubMed

Srivastava, Samanvaya; Reddy, P Dinesh Sankar; Wang, Cindy; Bandyopadhyay, Dipankar; Sharma, Ashutosh

2010-05-07

We study by nonlinear simulations the electric field induced pattern formation in a thin viscous film resting on a topographically or chemically patterned substrate. The thin film microstructures can be aligned to the substrate patterns within a window of parameters where the spinodal length scale of the field induced instability is close to the substrate periodicity. We investigate systematically the change in the film morphology and order when (i) the substrate pattern periodicity is varied at a constant film thickness and (ii) the film thickness is varied at a constant substrate periodicity. Simulations show two distinct pathway of evolution when the substrate-topography changes from protrusions to cavities. The isolated substrate defects generate locally ordered ripplelike structures distinct from the structures on a periodically patterned substrate. In the latter case, film morphology is governed by a competition between the pattern periodicity and the length scale of instability. Relating the thin film morphologies to the underlying substrate pattern has implications for field induced patterning and robustness of inter-interface pattern transfer, e.g., coding-decoding of information printed on a substrate.

Distinct Morphology of Human T-Cell Leukemia Virus Type 1-Like Particles

PubMed Central

Maldonado, José O.; Cao, Sheng; Zhang, Wei; Mansky, Louis M.

2016-01-01

The Gag polyprotein is the main retroviral structural protein and is essential for the assembly and release of virus particles. In this study, we have analyzed the morphology and Gag stoichiometry of human T-cell leukemia virus type 1 (HTLV-1)-like particles and authentic, mature HTLV-1 particles by using cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission electron microscopy (STEM). HTLV-1-like particles mimicked the morphology of immature authentic HTLV-1 virions. Importantly, we have observed for the first time that the morphology of these virus-like particles (VLPs) has the unique local feature of a flat Gag lattice that does not follow the curvature of the viral membrane, resulting in an enlarged distance between the Gag lattice and the viral membrane. Other morphological features that have been previously observed with other retroviruses include: (1) a Gag lattice with multiple discontinuities; (2) membrane regions associated with the Gag lattice that exhibited a string of bead-like densities at the inner leaflet; and (3) an arrangement of the Gag lattice resembling a railroad track. Measurement of the average size and mass of VLPs and authentic HTLV-1 particles suggested a consistent range of size and Gag copy numbers in these two groups of particles. The unique local flat Gag lattice morphological feature observed suggests that HTLV-1 Gag could be arranged in a lattice structure that is distinct from that of other retroviruses characterized to date. PMID:27187442

Genome-wide SNP data and morphology support the distinction of two new species of Kovarikia Soleglad, Fet & Graham, 2014 endemic to California (Scorpiones, Vaejovidae)

USGS Publications Warehouse

Bryson, Robert W.; Wood, Dustin A.; Graham, Matthew R.; Soleglad, Michael E.; McCormack, John E.

2018-01-01

Morphologically conserved taxa such as scorpions represent a challenge to delimit. We recently discovered populations of scorpions in the genus Kovarikia Soleglad, Fet & Graham, 2014 on two isolated mountain ranges in southern California. We generated genome-wide single nucleotide polymorphism data and used Bayes factors species delimitation to compare alternative species delimitation scenarios which variously placed scorpions from the two localities with geographically adjacent species or into separate lineages. We also estimated a time-calibrated phylogeny of Kovarikia and examined and compared the morphology of preserved specimens from across its distribution. Genetic results strongly support the distinction of two new lineages, which we describe and name here. Morphology among the species of Kovarikia was relatively conserved, despite deep genetic divergences, consistent with recent studies of stenotopic scorpions with limited vagility. Phylogeographic structure discovered in several previously described species also suggests additional cryptic species are probably present in the genus.

Morphological, Structural and Optical Evolution of Ag Nanostructures on c-Plane GaN Through the Variation of Deposition Amount and Temperature

NASA Astrophysics Data System (ADS)

Sui, Mao; Li, Ming-Yu; Pandey, Puran; Zhang, Quanzhen; Kunwar, Sundar; Lee, Jihoon

2018-03-01

Owing to their tunable properties, Ag nanostructures have been widely adapted in various applications and the morphological control can determine their performance and effectiveness. In this work, we demonstrate the morphological and optical evolution of Ag nanostructures on GaN (0001) by the systematic control of deposition amount at two distinctive annealing temperatures. Based on the Volmer-Weber and coalescence growth models, the nanostructure growth commenced by the thermal solid-state-dewetting evolve in terms of size, density and configuration. At 450 °C, the round-dome shaped Ag nanoparticles (regime I), irregular Ag nano-mounds (regime II) and void-layer structures (regime III) are observed along with the gradually increased deposition amount. As a sharp distinction, the solid state dewetting process occur more radically at 700 °C and also, the Ag sublimation and the effect on the nanostructure formation are observed in a clear regime shift scaled by the deposition amount. Meanwhile, a strong dependency of reflectance spectra evolution on the Ag nanostructure morphology is witnessed for both sets. In particular, Ag dipolar resonance peaks are significantly red-shifted from VIS to NIR regions along with the nanostructure evolution. The reflectance, PL and Raman intensity variation are also observed and discussed based on the evolution of Ag nanostructures.

Morphological structure mediates the notional meaning of gender marking: Evidence from the gender-congruency effect in Hebrew speech production.

PubMed

Deutsch, Avital; Dank, Maya

2018-02-01

This study investigated the gender-congruency effect of animate nouns in Hebrew. The Picture-Word Interference paradigm was used to manipulate gender congruency between target pictures and spoken distractors. Naming latency revealed an inhibitory gender-congruency effect, as naming the pictures took longer in the presence of a gender-congruent distractor than with a distractor from a different gender category. The inhibitory effect was demonstrated for feminine (morphologically marked) nouns, across two stimulus-onset asynchronies (SOAs) (Experiments 1a and 1b), and masculine (morphologically unmarked) nouns (Experiment 2). The same pattern was observed when participants had to produce bare nouns (Experiment 1) or gender-marked noun phrases (Experiment 3). The inhibitory pattern of the effect resembles previous findings of bare nouns in a subset of Romance languages, including Italian and Spanish. These findings add to previous research which investigated the gender-congruency effect of inanimate nouns, where no effect of gender-congruent words was found. The results are discussed in relation to the null effect previously found for inanimate nouns. The comparison of the present and previous studies is motivated by a common linguistic distinction between animate and inanimate nouns in Hebrew, which ascribes grammatical gender specifications to derivational structures (for inanimate nouns) versus inflectional structures (for animate nouns). Given the difference in the notional meaning of gender specification for animate and inanimate nouns, the case of Hebrew exemplifies how language-specific characteristics, such as rich morphological structures, can be used by the linguistic system to express conceptual distinctions at the form-word level.

The neural correlates of morphological complexity processing: Detecting structure in pseudowords.

PubMed

Schuster, Swetlana; Scharinger, Mathias; Brooks, Colin; Lahiri, Aditi; Hartwigsen, Gesa

2018-06-01

Morphological complexity is a highly debated issue in visual word recognition. Previous neuroimaging studies have shown that speakers are sensitive to degrees of morphological complexity. Two-step derived complex words (bridging through bridge N  > bridge V  > bridging) led to more enhanced activation in the left inferior frontal gyrus than their 1-step derived counterparts (running through run V  > running). However, it remains unclear whether sensitivity to degrees of morphological complexity extends to pseudowords. If this were the case, it would indicate that abstract knowledge of morphological structure is independent of lexicality. We addressed this question by investigating the processing of two sets of pseudowords in German. Both sets contained morphologically viable two-step derived pseudowords differing in the number of derivational steps required to access an existing lexical representation and therefore the degree of structural analysis expected during processing. Using a 2 × 2 factorial design, we found lexicality effects to be distinct from processing signatures relating to structural analysis in pseudowords. Semantically-driven processes such as lexical search showed a more frontal distribution while combinatorial processes related to structural analysis engaged more parietal parts of the network. Specifically, more complex pseudowords showed increased activation in parietal regions (right superior parietal lobe and left precuneus) relative to pseudowords that required less structural analysis to arrive at an existing lexical representation. As the two sets were matched on cohort size and surface form, these results highlight the role of internal levels of morphological structure even in forms that do not possess a lexical representation. © 2018 Wiley Periodicals, Inc.

Recognition-Mediated Assembly of Quantum Dot Polymer Conjugates with Controlled Morphology

PubMed Central

Nandwana, Vikas; Subramani, Chandramouleeswaran; Eymur, Serkan; Yeh, Yi-Cheun; Tonga, Gulen Yesilbag; Tonga, Murat; Jeong, Youngdo; Yang, Boqian; Barnes, Michael D.; Cooke, Graeme; Rotello, Vincent M.

2011-01-01

We have demonstrated a polymer mediated “bricks and mortar” method for the self-assembly of quantum dots (QDs). This strategy allows QDs to self-assemble into structured aggregates using complementary three-point hydrogen bonding. The resulting nanocomposites have distinct morphologies and inter-particle distances based on the ratio between QDs and polymer. Time resolved photoluminescence measurements showed that the optical properties of the QDs were retained after self-assembly. PMID:22016664

The Morphologies of the Semiconductor Oxides and Their Gas-Sensing Properties

PubMed Central

Lv, Xin; Li, Shuang; Wang, Qingji

2017-01-01

Semiconductor oxide chemoresistive gas sensors are widely used for detecting deleterious gases due to low cost, simple preparation, rapid response and high sensitivity. The performance of gas sensor is greatly affected by the morphology of the semiconductor oxide. There are many semiconductor oxide morphologies, including zero-dimensional, one-dimensional, two-dimensional and three-dimensional ones. The semiconductor oxides with different morphologies significantly enhance the gas-sensing performance. Among the various morphologies, hollow nanostructures and core-shell nanostructures are always the focus of research in the field of gas sensors due to their distinctive structural characteristics and superior performance. Herein the morphologies of semiconductor oxides and their gas-sensing properties are reviewed. This review also proposes a potential strategy for the enhancement of gas-sensing performance in the future. PMID:29189714

Clinically relevant morphological structures in breast cancer represent transcriptionally distinct tumor cell populations with varied degrees of epithelial-mesenchymal transition and CD44+CD24- stemness

PubMed Central

Denisov, Evgeny V.; Skryabin, Nikolay A.; Gerashchenko, Tatiana S.; Tashireva, Lubov A.; Wilhelm, Jochen; Buldakov, Mikhail A.; Sleptcov, Aleksei A.; Lebedev, Igor N.; Vtorushin, Sergey V.; Zavyalova, Marina V.; Cherdyntseva, Nadezhda V.; Perelmuter, Vladimir M.

2017-01-01

Intratumor morphological heterogeneity in breast cancer is represented by different morphological structures (tubular, alveolar, solid, trabecular, and discrete) and contributes to poor prognosis; however, the mechanisms involved remain unclear. In this study, we performed 3D imaging, laser microdissection-assisted array comparative genomic hybridization and gene expression microarray analysis of different morphological structures and examined their association with the standard immunohistochemistry scorings and CD44+CD24- cancer stem cells. We found that the intratumor morphological heterogeneity is not associated with chromosomal aberrations. By contrast, morphological structures were characterized by specific gene expression profiles and signaling pathways and significantly differed in progesterone receptor and Ki-67 expression. Most importantly, we observed significant differences between structures in the number of expressed genes of the epithelial and mesenchymal phenotypes and the association with cancer invasion pathways. Tubular (tube-shaped) and alveolar (spheroid-shaped) structures were transcriptionally similar and demonstrated co-expression of epithelial and mesenchymal markers. Solid (large shapeless) structures retained epithelial features but demonstrated an increase in mesenchymal traits and collective cell migration hallmarks. Mesenchymal genes and cancer invasion pathways, as well as Ki-67 expression, were enriched in trabecular (one/two rows of tumor cells) and discrete groups (single cells and/or arrangements of 2-5 cells). Surprisingly, the number of CD44+CD24- cells was found to be the lowest in discrete groups and the highest in alveolar and solid structures. Overall, our findings indicate the association of intratumor morphological heterogeneity in breast cancer with the epithelial-mesenchymal transition and CD44+CD24- stemness and the appeal of this heterogeneity as a model for the study of cancer invasion. PMID:28977854

Substrate effect on nanoporous structure of silica wires by channel-confined self-assembly of block-copolymer and sol-gel precursors

DOE PAGES

Hu, Michael Z.; Lai, Peng

2015-09-22

Nanoporous silica wires of various wire diameters were developed by space-confined molecular self-assembly of triblock copolymer ethylene/propylene/ethylene (P123) and silica alkoxide precursor (tetraethylorthosilicate, TEOS). Two distinctive hard-templating substrates, anodized aluminum oxide (AAO) and track-etched polycarbonate (EPC), with channel diameters in the range between 10 nm and 200 nm were employed for space-confinement of soft molecular self-assembly driven by the block-copolymer microphase separation. It was observed in the scanning and transmission electron microscope (STEM) studies that the substrate geometry and material characteristics had pronounced effects on the structure and morphology of the silica nanowires. A substrate wall effect was proposed tomore » explain the ordering and orientation of the intra-wire mesostructure. Circular and spiral nanostructures were found only in wires formed in AAO substrate, not in EPC. Pore-size differences and distinctive wall morphologies of the nanowires relating to the substrates were discussed. It was shown that the material and channel wall characteristics of different substrates play key roles in the ordering and morphology of the intra-wire nanostructures.« less

Variation in tooth morphology of Gorilla gorilla.

PubMed

Uchida, A

1998-01-01

Gorilla gorilla exemplifies a species that shows considerable variation in habitat, behaviour, genetic structure and morphology. This study examines variation of dental morphology in gorillas. Despite the marked size dimorphism, there are no significant shape differences between the sexes within subspecies. Differences in dental morphology, including tooth cusp proportions between the western G. g. gorilla and the eastern G. g. beringei are considerable. Although more similar to G. g. beringei than to the western G. g. gorilla, G. g. graueri also shows distinct morphological features. This indicates that the morphology of G. g. graueri is not merely intermediate, and genetic isolation between the two eastern subspecies could have had a substantial influence. Such extensive variation in dental morphology in Gorilla gorilla can be considered to be the result of an interesting combination of factors, including local dietary adaptations.

Morphology and dynamics of explosive vents

NASA Astrophysics Data System (ADS)

Gisler, Galen R.; Galland, Olivier; Haug, Øystein T.

2014-05-01

Eruptive processes in nature produce a wide variety of morphologies, including cone sheets, dykes, sills, and pipes. The choice of a particular eruptive style is determined partly by local inhomogeneities, and partly by the gross overall properties of the country rock and the physical properties of the eruptive fluid. In this study we report on experimental and numerical designed to capture a range of morphologies in an eruptive system. Using dimensional analysis we link the experimental and numerical work together and draw implications for field studies. Our experimental work uses silica flour in a Hele-Shaw cell, with air as the eruptive fluid. A phase diagram demonstrates a separation between two distinct morphologies, with vertical structures occurring at high pressure or low depth of fill and diagonal ones at low pressure or high depth of fill. In the numerical work the eruptive fluid is a mixture of basaltic magma, supercritical water, and carbon dioxide, and the ambient material is a fill of basalt with varying material properties. In the numerical work we see three distinct morphologies: vertical pipes are produced at high pressures and softer backgrounds, diagonal pipes at lower pressures and stiffer backgrounds, while horizontal sills are produced in intermediate regimes.

Distinct Annular Oligomers Captured along the Assembly and Disassembly Pathways of Transthyretin Amyloid Protofibrils

PubMed Central

Pires, Ricardo H.; Karsai, Árpád; Saraiva, Maria J.; Damas, Ana M.; Kellermayer, Miklós S. Z.

2012-01-01

Background Defects in protein folding may lead to severe degenerative diseases characterized by the appearance of amyloid fibril deposits. Cytotoxicity in amyloidoses has been linked to poration of the cell membrane that may involve interactions with amyloid intermediates of annular shape. Although annular oligomers have been detected in many amyloidogenic systems, their universality, function and molecular mechanisms of appearance are debated. Methodology/Principal Findings We investigated with high-resolution in situ atomic force microscopy the assembly and disassembly of transthyretin (TTR) amyloid protofibrils formed of the native protein by pH shift. Annular oligomers were the first morphologically distinct intermediates observed in the TTR aggregation pathway. Morphological analysis suggests that they can assemble into a double-stack of octameric rings with a 16±2 nm diameter, and displaying the tendency to form linear structures. According to light scattering data coupled to AFM imaging, annular oligomers appeared to undergo a collapse type of structural transition into spheroid oligomers containing 8–16 monomers. Disassembly of TTR amyloid protofibrils also resulted in the rapid appearance of annular oligomers but with a morphology quite distinct from that observed in the assembly pathway. Conclusions/Significance Our observations indicate that annular oligomers are key dynamic intermediates not only in the assembly but also in the disassembly of TTR protofibrils. The balance between annular and more compact forms of aggregation could be relevant for cytotoxicity in amyloidogenic disorders. PMID:22984597

Nematode-associated microbial taxa do not correlate with host phylogeny, geographic region or feeding morphology in marine sediment habitats.

PubMed

Schuelke, Taruna; Pereira, Tiago José; Hardy, Sarah M; Bik, Holly M

2018-04-01

Studies of host-associated microbes are critical for advancing our understanding of ecology and evolution across diverse taxa and ecosystems. Nematode worms are ubiquitous across most habitats on earth, yet little is known about host-associated microbial assemblages within the phylum. Free-living nematodes are globally abundant and diverse in marine sediments, with species exhibiting distinct buccal cavity (mouth) morphologies that are thought to play an important role in feeding ecology and life history strategies. Here, we investigated patterns in marine nematode microbiomes, by characterizing host-associated microbial taxa in 281 worms isolated from a range of habitat types (deep-sea, shallow water, methane seeps, Lophelia coral mounds, kelp holdfasts) across three distinct geographic regions (Arctic, Southern California and Gulf of Mexico). Microbiome profiles were generated from single worms spanning 33 distinct morphological genera, using a two-gene metabarcoding approach to amplify the V4 region of the 16S ribosomal RNA (rRNA) gene targeting bacteria/archaea and the V1-V2 region of the 18S rRNA gene targeting microbial eukaryotes. Contrary to our expectations, nematode microbiome profiles demonstrated no distinct patterns either globally (across depths and ocean basins) or locally (within site); prokaryotic and eukaryotic microbial assemblages did not correlate with nematode feeding morphology, host phylogeny or morphological identity, ocean region or marine habitat type. However, fine-scale analysis of nematode microbiomes revealed a variety of novel ecological interactions, including putative parasites and symbionts, and potential associations with bacterial/archaeal taxa involved in nitrogen and methane cycling. Our results suggest that in marine habitats, free-living nematodes may utilize diverse and generalist foraging strategies that are not correlated with host genotype or feeding morphology. Furthermore, some abiotic factors such as geographic region and habitat type do not appear to play an obvious role in structuring host-microbe associations or feeding preferences. © 2018 John Wiley & Sons Ltd.

Antarctic glossopterid diversity on a local scale: the presence of multiple megasporophyll genera, Upper Permian, Mt. Achernar, Transantarctic Mountains, Antarctica.

PubMed

Ryberg, Patricia E; Taylor, Edith L; Taylor, Thomas N

2012-09-01

The glossopterids are a group of plants that thrived during a time of global warming similar to what is happening on the Earth today as well as the transition from archaic plant groups to the ancestors of modern groups. The diversity of the glossopterid clade is based on the megasporangiate structures assigned to the group, because the vegetative and pollen-bearing structures vary little. The presence of numerous reproductive genera from a single Upper Permian locality in the central Transantarctic Mountains provides important data on local glossopterid diversity in Antarctica. Impression/compression fossils were imaged with a Leica 5000C digital camera on a dissecting microscope or a Fujifilm FinePix S1pro digital camera. Two megasporangiate taxa are described: Scutum leiophyllum, which represents the first confirmed record of the genus in Antarctica, and Lidgettoniopsis ramulus, a new morphology consisting of a pinnate structure with oppositely attached megasporophylls. Plumsteadia ovata specimens indicate that this genus can be larger than previously recorded and illustrate the vegetative surface with a distinct midrib. The presence of a laminar, multiovulate structure and a pinnate structure at the same site indicates that local-level glossopterid diversity in Antarctica is greater than previously hypothesized. The discovery of a new megasporophyll morphology in Antarctica (confirming the presence of three distinctive morphologies on the continent) shows that Antarctic glossopterid heterogeneity is on a par with other Gondwanan continents. The diversity of the Antarctic landscape reveals that high polar latitudes can sustain a diverse ecosystem during times of global warming.

Nanomechanical properties of distinct fibrillar polymorphs of the protein α-synuclein.

PubMed

Makky, Ali; Bousset, Luc; Polesel-Maris, Jérôme; Melki, Ronald

2016-11-30

Alpha-synuclein (α-Syn) is a small presynaptic protein of 140 amino acids. Its pathologic intracellular aggregation within the central nervous system yields protein fibrillar inclusions named Lewy bodies that are the hallmarks of Parkinson's disease (PD). In solution, pure α-Syn adopts an intrinsically disordered structure and assembles into fibrils that exhibit considerable morphological heterogeneity depending on their assembly conditions. We recently established tightly controlled experimental conditions allowing the assembly of α-Syn into highly homogeneous and pure polymorphs. The latter exhibited differences in their shape, their structure but also in their functional properties. We have conducted an AFM study at high resolution and performed a statistical analysis of fibrillar α-Syn shape and thermal fluctuations to calculate the persistence length to further assess the nanomechanical properties of α-Syn polymorphs. Herein, we demonstrated quantitatively that distinct polymorphs made of the same protein (wild-type α-Syn) show significant differences in their morphology (height, width and periodicity) and physical properties (persistence length, bending rigidity and axial Young's modulus).

Architecture and biogenesis of plus-strand RNA virus replication factories

PubMed Central

Paul, David; Bartenschlager, Ralf

2013-01-01

Plus-strand RNA virus replication occurs in tight association with cytoplasmic host cell membranes. Both, viral and cellular factors cooperatively generate distinct organelle-like structures, designated viral replication factories. This compartmentalization allows coordination of the different steps of the viral replication cycle, highly efficient genome replication and protection of the viral RNA from cellular defense mechanisms. Electron tomography studies conducted during the last couple of years revealed the three dimensional structure of numerous plus-strand RNA virus replication compartments and highlight morphological analogies between different virus families. Based on the morphology of virus-induced membrane rearrangements, we propose two separate subclasses: the invaginated vesicle/spherule type and the double membrane vesicle type. This review discusses common themes and distinct differences in the architecture of plus-strand RNA virus-induced membrane alterations and summarizes recent progress that has been made in understanding the complex interplay between viral and co-opted cellular factors in biogenesis and maintenance of plus-strand RNA virus replication factories. PMID:24175228

Nanomechanical properties of distinct fibrillar polymorphs of the protein α-synuclein

NASA Astrophysics Data System (ADS)

Makky, Ali; Bousset, Luc; Polesel-Maris, Jérôme; Melki, Ronald

2016-11-01

Alpha-synuclein (α-Syn) is a small presynaptic protein of 140 amino acids. Its pathologic intracellular aggregation within the central nervous system yields protein fibrillar inclusions named Lewy bodies that are the hallmarks of Parkinson’s disease (PD). In solution, pure α-Syn adopts an intrinsically disordered structure and assembles into fibrils that exhibit considerable morphological heterogeneity depending on their assembly conditions. We recently established tightly controlled experimental conditions allowing the assembly of α-Syn into highly homogeneous and pure polymorphs. The latter exhibited differences in their shape, their structure but also in their functional properties. We have conducted an AFM study at high resolution and performed a statistical analysis of fibrillar α-Syn shape and thermal fluctuations to calculate the persistence length to further assess the nanomechanical properties of α-Syn polymorphs. Herein, we demonstrated quantitatively that distinct polymorphs made of the same protein (wild-type α-Syn) show significant differences in their morphology (height, width and periodicity) and physical properties (persistence length, bending rigidity and axial Young’s modulus).

New multi-scale perspectives on the stromatolites of Shark Bay, Western Australia.

PubMed

Suosaari, E P; Reid, R P; Playford, P E; Foster, J S; Stolz, J F; Casaburi, G; Hagan, P D; Chirayath, V; Macintyre, I G; Planavsky, N J; Eberli, G P

2016-02-03

A recent field-intensive program in Shark Bay, Western Australia provides new multi-scale perspectives on the world's most extensive modern stromatolite system. Mapping revealed a unique geographic distribution of morphologically distinct stromatolite structures, many of them previously undocumented. These distinctive structures combined with characteristic shelf physiography define eight 'Stromatolite Provinces'. Morphological and molecular studies of microbial mat composition resulted in a revised growth model where coccoid cyanobacteria predominate in mat communities forming lithified discrete stromatolite buildups. This contradicts traditional views that stromatolites with the best lamination in Hamelin Pool are formed by filamentous cyanobacterial mats. Finally, analysis of internal fabrics of stromatolites revealed pervasive precipitation of microcrystalline carbonate (i.e. micrite) in microbial mats forming framework and cement that may be analogous to the micritic microstructures typical of Precambrian stromatolites. These discoveries represent fundamental advances in our knowledge of the Shark Bay microbial system, laying a foundation for detailed studies of stromatolite morphogenesis that will advance our understanding of benthic ecosystems on the early Earth.

Selective nucleation of iron phthalocyanine crystals on micro-structured copper iodide.

PubMed

Rochford, Luke A; Ramadan, Alexandra J; Heutz, Sandrine; Jones, Tim S

2014-12-14

Morphological and structural control of organic semiconductors through structural templating is an efficient route by which to tune their physical properties. The preparation and characterisation of iron phthalocyanine (FePc)-copper iodide (CuI) bilayers at elevated substrate temperatures is presented. Thin CuI(111) layers are prepared which are composed of isolated islands rather than continuous films previously employed in device structures. Nucleation in the early stages of FePc growth is observed at the edges of islands rather than on the top (111) faces with the use of field emission scanning electron microscopy (FE-SEM). Structural measurements show two distinct polymorphs of FePc, with CuI islands edges nucleating high aspect ratio FePc crystallites with modified intermolecular spacing. By combining high substrate temperature growth and micro-structuring of the templating CuI(111) layer structural and morphological control of the organic film is demonstrated.

Wrinkle ridge-upland scarp transitions: Implications for the mechanical properties of the deformed materials

NASA Technical Reports Server (NTRS)

Watters, Thomas R.; Tuttle, Michael J.; Simpson, Debra

1991-01-01

Wrinkle ridge-upland scarp transitions are structures that occur at the contact between smooth plains material and highlands or uplands materials on the Moon and Mars. In the smooth plains material the structures have a morphology typical of wrinkle ridges, interpreted to be the result of a combination of folding and thrust faulting. Where the structures extend into the uplands, a distinct change in the morphology occurs. The generally asymmetric cross sectional geometry characteristics of wrinkle ridges becomes that of a one-sided, often lobate scarp. The scarp is indistinguishable from other highland/upland scarps, interpreted to be the result of reverse or thrust faulting. Although these structures are rare, they provide important insight into the mechanical properties of deformed materials. These insights are discussed.

Morphological effects in children word reading: a priming study in fourth graders.

PubMed

Casalis, Séverine; Dusautoir, Marion; Colé, Pascale; Ducrot, Stéphanie

2009-09-01

A growing corpus of evidence suggests that morphology could play a role in reading acquisition, and that young readers could be sensitive to the morphemic structure of written words. In the present experiment, we examined whether and when morphological information is activated in word recognition. French fourth graders made visual lexical decisions to derived words preceded by primes sharing either a morphological or an orthographic relationship with the target. Results showed significant and equivalent facilitation priming effects in cases of morphologically and orthographically related primes at the shortest prime duration, and a significant facilitation priming effect in the case of only morphologically related primes at the longer prime duration. Thus, these results strongly suggest that a morphological level is involved in children's visual word recognition, although it is not distinct from the formal one at an early stage of word processing.

Three Distinct Deformation Behaviors of Cementite Lamellae in a Cold-Drawn Pearlitic Wire

NASA Astrophysics Data System (ADS)

Xin, Tuo; Liu, Guiju; Liang, Wenshuang; Cai, Rongsheng; Feng, Honglei; Li, Chen; Li, Jian; Wang, Yiqian

2018-03-01

High-resolution transmission electron microscopy is used to investigate the deformation behaviors of cementite lamellae in the heavily cold-drawn piano wires. Three distinct morphologies of cementite are observed, namely, complete lamella, partly-broken lamella and nearly-disappeared lamella. For the complete cementite lamella, it remains a single-crystalline structure. For the partly-broken cementite lamella, polycrystalline structure and neck-down region appear to release the residual strain. The lattice expansion of ferrite takes place in two perpendicular directions indicating that the carbon atoms dissolve from cementite into ferrite lattices. An orientation relationship is found between ferrite and cementite phases in the cold-drawn pearlitic wire.

Spatial genetic and morphologic structure of wolves and coyotes in relation to environmental heterogeneity in a Canis hybrid zone.

PubMed

Benson, John F; Patterson, Brent R; Wheeldon, Tyler J

2012-12-01

Eastern wolves have hybridized extensively with coyotes and gray wolves and are listed as a 'species of special concern' in Canada. However, a distinct population of eastern wolves has been identified in Algonquin Provincial Park (APP) in Ontario. Previous studies of the diverse Canis hybrid zone adjacent to APP have not linked genetic analysis with field data to investigate genotype-specific morphology or determine how resident animals of different ancestry are distributed across the landscape in relation to heterogeneous environmental conditions. Accordingly, we studied resident wolves and coyotes in and adjacent to APP to identify distinct Canis types, clarify the extent of the APP eastern wolf population beyond the park boundaries and investigate fine-scale spatial genetic structure and landscape-genotype associations in the hybrid zone. We documented three genetically distinct Canis types within the APP region that also differed morphologically, corresponding to putative gray wolves, eastern wolves and coyotes. We also documented a substantial number of hybrid individuals (36%) that were admixed between 2 or 3 of the Canis types. Breeding eastern wolves were less common outside of APP, but occurred in some unprotected areas where they were sympatric with a diverse combination of coyotes, gray wolves and hybrids. We found significant spatial genetic structure and identified a steep cline extending west from APP where the dominant genotype shifted abruptly from eastern wolves to coyotes and hybrids. The genotypic pattern to the south and northwest was a more complex mosaic of alternating genotypes. We modelled genetic ancestry in response to prey availability and human disturbance and found that individuals with greater wolf ancestry occupied areas of higher moose density and fewer roads. Our results clarify the structure of the Canis hybrid zone adjacent to APP and provide unique insight into environmental conditions influencing hybridization dynamics between wolves and coyotes. © 2012 Blackwell Publishing Ltd.

Evaluation of the genetic structure present in natural populations of four subspecies of black cherry (Prunus serotina Ehrh.) from North America using SSR markers

USDA-ARS?s Scientific Manuscript database

Black cherry (Prunus serotina) is a fruit tree native to North America, and almost all parts of this plant have some use. This species is a complex of five subspecies with morphological differences and distinctive habitats. The genetic structure of 18 natural populations of black cherry was evaluate...

Thermally Induced Structural Evolution and Performance of Mesoporous Block Copolymer-Directed Alumina Perovskite Solar Cells

PubMed Central

2015-01-01

Structure control in solution-processed hybrid perovskites is crucial to design and fabricate highly efficient solar cells. Here, we utilize in situ grazing incidence wide-angle X-ray scattering and scanning electron microscopy to investigate the structural evolution and film morphologies of methylammonium lead tri-iodide/chloride (CH3NH3PbI3–xClx) in mesoporous block copolymer derived alumina superstructures during thermal annealing. We show the CH3NH3PbI3–xClx material evolution to be characterized by three distinct structures: a crystalline precursor structure not described previously, a 3D perovskite structure, and a mixture of compounds resulting from degradation. Finally, we demonstrate how understanding the processing parameters provides the foundation needed for optimal perovskite film morphology and coverage, leading to enhanced block copolymer-directed perovskite solar cell performance. PMID:24684494

A Recipe for Soft Fluidic Elastomer Robots

PubMed Central

Marchese, Andrew D.; Katzschmann, Robert K.

2015-01-01

Abstract This work provides approaches to designing and fabricating soft fluidic elastomer robots. That is, three viable actuator morphologies composed entirely from soft silicone rubber are explored, and these morphologies are differentiated by their internal channel structure, namely, ribbed, cylindrical, and pleated. Additionally, three distinct casting-based fabrication processes are explored: lamination-based casting, retractable-pin-based casting, and lost-wax-based casting. Furthermore, two ways of fabricating a multiple DOF robot are explored: casting the complete robot as a whole and casting single degree of freedom (DOF) segments with subsequent concatenation. We experimentally validate each soft actuator morphology and fabrication process by creating multiple physical soft robot prototypes. PMID:27625913

A Recipe for Soft Fluidic Elastomer Robots.

PubMed

Marchese, Andrew D; Katzschmann, Robert K; Rus, Daniela

2015-03-01

This work provides approaches to designing and fabricating soft fluidic elastomer robots. That is, three viable actuator morphologies composed entirely from soft silicone rubber are explored, and these morphologies are differentiated by their internal channel structure, namely, ribbed, cylindrical, and pleated. Additionally, three distinct casting-based fabrication processes are explored: lamination-based casting, retractable-pin-based casting, and lost-wax-based casting. Furthermore, two ways of fabricating a multiple DOF robot are explored: casting the complete robot as a whole and casting single degree of freedom (DOF) segments with subsequent concatenation. We experimentally validate each soft actuator morphology and fabrication process by creating multiple physical soft robot prototypes.

Distinct phylogeographic structure recognized within Desmazierella acicola.

PubMed

Martinović, Tijana; Koukol, Ondřej; Hirose, Dai

2016-01-01

Desmazierella acicola (anamorph Verticicladium trifidum, Chorioactidaceae) represents a frequent colonizer of pine needles in litter. Considering the global diversity and distribution of pine species, we expected different phylogenetic lineages to exist in different geographical and climatic areas inhabited by these hosts. We compared DNA sequence data with phenotypic characteristics (morphology of the anamorph and growth at three different temperatures) of 43 strains isolated mostly from pine and also spruce needle litter sampled in various geographical areas. Analyses of ITS rDNA recovered eight geographically structured lineages. Fragments of genes for the translation elongation factor 1-α, and the second largest subunit of RNA polymerase II reproduced similar lineages, although not all of them were monophyletic. The similarity in ITS sequences among the clade with samples from Continental-Atlantic Europe and four other clades was lower than 95%. Several lineages exhibit also a tendency toward host specificity to a particular pine species. Growth tests at different temperatures indicated a different tolerance to specific climatic conditions in different geographic areas. However, the surveyed phenotypic characteristics also showed high variation within lineages, most evident in the morphology of the anamorph. Until a morphological study of the teleomorph is carried out, all of these lineages should be treated as distinct populations within a single species. © 2016 by The Mycological Society of America.

Cutaneous microcystic/reticular schwannoma: a poorly recognized entity.

PubMed

Luzar, Boštjan; Tanaka, Maiko; Schneider, Johann; Calonje, Eduardo

2016-02-01

Microcystic/ reticular schwannoma is exceptionally rare yet distinctive morphological variant of schwannoma with predilection for visceral sites lacking association with neurofibromatosis. To further delineate clinicopathological features of cutaneous microcystic/reticular schwannoma and to discuss its differential diagnosis. We analyzed three cutaneous microcystic/reticular schwannomas, occurring in two males and one female (mean age: 37.6 years). The tumors presented as a non-painful slightly raised papule (mean: 0.7 cm) on upper arm (n = 2) and back (n = 1). No recurrences were observed despite marginal excision (mean follow up: 42 months). Histopathologically, a multilobular proliferation was present in the dermis composed of bland tumor cells forming distinctive microcystic, reticular, lace-like or pseudoglandular structures, containing abundant myxoid/mucinous material. By immunohistochemistry, tumor cells lining microcystic structures corresponded to Schwann cells (diffuse S100 positive, variable GFAP positivity). A discontinuous EMA-positive perineurium was present at the periphery of some of the lobules. Cutaneous microcystic/reticular schwannoma expands the spectrum of benign peripheral nerve sheath tumors with reticular morphology encountered in the skin. Other tumors in this group include reticular perineurioma and hybrid tumors with reticular morphology, e.g. reticular perineurioma/schwannoma and reticular perineurioma/neurofibroma. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Precursor-controlled synthesis of hierarchical ZnO nanostructures, using oligoaniline-coated Au nanoparticle seeds

NASA Astrophysics Data System (ADS)

Krishnan, Deepti; Pradeep, T.

2009-07-01

Shape-selected synthesis of a large number of zinc oxide (ZnO) nano- and microstructures was achieved by the seed-mediated growth of oligoaniline-coated gold nanoparticle precursors. Distinctive ZnO structures such as nanoplates, nanospheres, microstars, microflowers, microthorns and micromultipods were synthesized by this method. Slightly different shapes were obtained in the absence of the seed solution. This is a fast, low temperature (60 °C) and biomimetic route to make a wide variety of structures. The structure and morphology of the nanostructures were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were utilized for the characterization of the nanostructures. A growth mechanism for these nanostructures was proposed based on these results. The concentrations of the reacting species were the main parameter causing the changes in the morphologies. The variation in morphologies of these structures is believed to be due to the ability of the seed solution as well as polyvinylpyrrolidone (PVP) to selectively suppress/depress the growth of certain planes, allowing growth to occur only in certain specific directions. Changes in the amount of growth nuclei with varying sodium hydroxide (NaOH) concentration is also seen to affect the morphology of these structures.

The Effect of Oscillating Traverse Welding on Performance of Cr-Fe-C Hardfacing Alloys

NASA Astrophysics Data System (ADS)

Lai, Hsuan-Han; Hsieh, Chih-Chun; Wang, Jia-Siang; Lin, Chi-Ming; Wu, Weite

2015-11-01

In this study, a series of experiments involving Cr-Fe-C hardfacing alloys is conducted to evaluate the effect of oscillating traverse welding on microstructure and performance of clad alloys. The alloys are designed to exhibit hypoeutectic, eutectic, and hypereutectic morphology. The morphology of the heat-affected zone (HAZ) of the unmelted metal, the solidified remelted metal, and the fusion boundary exhibited distinct characteristics. In the hypoeutectic and the eutectic alloys, the same lamellar eutectic structure can be observed as the solidified structure, and they also showed the same evolution in the HAZ. In the hypereutectic alloy, the incomplete weld pool blending results in a eutectic morphology instead of a fully hypereutectic morphology. The hardness result reveals that, for the hypereutectic alloy, the eutectic region, instead of the HAZ, is the weak point. The wear test shows that the hypoeutectic alloy exhibits the same wear behaviors in both the remelted metal and the HAZ, and so is the hypereutectic alloy; the eutectic alloy remelted metal and the HAZ have different wear morphologies.

Genetic divergence between two phenotypically distinct bottlenose dolphin ecotypes suggests separate evolutionary trajectories.

PubMed

Fruet, Pedro F; Secchi, Eduardo R; Di Tullio, Juliana C; Simões-Lopes, Paulo César; Daura-Jorge, Fábio; Costa, Ana P B; Vermeulen, Els; Flores, Paulo A C; Genoves, Rodrigo Cezar; Laporta, Paula; Beheregaray, Luciano B; Möller, Luciana M

2017-11-01

Due to their worldwide distribution and occupancy of different types of environments, bottlenose dolphins display considerable morphological variation. Despite limited understanding about the taxonomic identity of such forms and connectivity among them at global scale, coastal (or inshore) and offshore (or oceanic) ecotypes have been widely recognized in several ocean regions. In the Southwest Atlantic Ocean (SWA), however, there are scarce records of bottlenose dolphins differing in external morphology according to habitat preferences that resemble the coastal-offshore pattern observed elsewhere. The main aim of this study was to analyze the genetic variability, and test for population structure between coastal ( n  = 127) and offshore ( n  = 45) bottlenose dolphins sampled in the SWA to assess whether their external morphological distinction is consistent with genetic differentiation. We used a combination of mtDNA control region sequences and microsatellite genotypes to infer population structure and levels of genetic diversity. Our results from both molecular marker types were congruent and revealed strong levels of structuring (microsatellites F ST  = 0.385, p  < .001; mtDNA F ST  =  0.183, p  < .001; Φ ST  = 0.385, p  < .001) and much lower genetic diversity in the coastal than the offshore ecotype, supporting patterns found in previous studies elsewhere. Despite the opportunity for gene flow in potential "contact zones", we found minimal current and historical connectivity between ecotypes, suggesting they are following discrete evolutionary trajectories. Based on our molecular findings, which seem to be consistent with morphological differentiations recently described for bottlenose dolphins in our study area, we recommend recognizing the offshore bottlenose dolphin ecotype as an additional Evolutionarily Significant Unit (ESU) in the SWA. Implications of these results for the conservation of bottlenose dolphins in SWA are also discussed.

Sponge budding is a spatiotemporal morphological patterning process: Insights from synchrotron radiation-based x-ray microtomography into the asexual reproduction of Tethya wilhelma.

PubMed

Hammel, Jörg U; Herzen, Julia; Beckmann, Felix; Nickel, Michael

2009-09-08

Primary agametic-asexual reproduction mechanisms such as budding and fission are present in all non-bilaterian and many bilaterian animal taxa and are likely to be metazoan ground pattern characters. Cnidarians display highly organized and regulated budding processes. In contrast, budding in poriferans was thought to be less specific and related to the general ability of this group to reorganize their tissues. Here we test the hypothesis of morphological pattern formation during sponge budding. We investigated the budding process in Tethya wilhelma (Demospongiae) by applying 3D morphometrics to high resolution synchrotron radiation-based x-ray microtomography (SR-muCT) image data. We followed the morphogenesis of characteristic body structures and identified distinct morphological states which indeed reveal characteristic spatiotemporal morphological patterns in sponge bud development. We discovered the distribution of skeletal elements, canal system and sponge tissue to be based on a sequential series of distinct morphological states. Based on morphometric data we defined four typical bud stages. Once they have reached the final stage buds are released as fully functional juvenile sponges which are morphologically and functionally equivalent to adult specimens. Our results demonstrate that budding in demosponges is considerably more highly organized and regulated than previously assumed. Morphological pattern formation in asexual reproduction with underlying genetic regulation seems to have evolved early in metazoans and was likely part of the developmental program of the last common ancestor of all Metazoa (LCAM).

Sponge budding is a spatiotemporal morphological patterning process: Insights from synchrotron radiation-based x-ray microtomography into the asexual reproduction of Tethya wilhelma

PubMed Central

Hammel, Jörg U; Herzen, Julia; Beckmann, Felix; Nickel, Michael

2009-01-01

Background Primary agametic-asexual reproduction mechanisms such as budding and fission are present in all non-bilaterian and many bilaterian animal taxa and are likely to be metazoan ground pattern characters. Cnidarians display highly organized and regulated budding processes. In contrast, budding in poriferans was thought to be less specific and related to the general ability of this group to reorganize their tissues. Here we test the hypothesis of morphological pattern formation during sponge budding. Results We investigated the budding process in Tethya wilhelma (Demospongiae) by applying 3D morphometrics to high resolution synchrotron radiation-based x-ray microtomography (SR-μCT) image data. We followed the morphogenesis of characteristic body structures and identified distinct morphological states which indeed reveal characteristic spatiotemporal morphological patterns in sponge bud development. We discovered the distribution of skeletal elements, canal system and sponge tissue to be based on a sequential series of distinct morphological states. Based on morphometric data we defined four typical bud stages. Once they have reached the final stage buds are released as fully functional juvenile sponges which are morphologically and functionally equivalent to adult specimens. Conclusion Our results demonstrate that budding in demosponges is considerably more highly organized and regulated than previously assumed. Morphological pattern formation in asexual reproduction with underlying genetic regulation seems to have evolved early in metazoans and was likely part of the developmental program of the last common ancestor of all Metazoa (LCAM). PMID:19737392

Assessing the biological contribution to microbialite growth and morphogenesis utilizing lipid biomarkers

NASA Astrophysics Data System (ADS)

Beeler, S. R.; Gomez, F. J.; Bradley, A. S.

2016-12-01

Microbialites are sedimentary structures that arise from the interaction of microbial, geochemical, and physical processes. These structures are among the oldest evidence for life on Earth, and are abundant through much of the Proterozoic before declining in the Phanerozoic. Microbialites are of great importance geobiologically as they provide a record of microbial life and its interaction with the environment throughout Earth history. Yet, our capacity to use microbialites to reconstruct biological processes on ancient Earth is complicated by our lack of understanding of the mechanisms controlling the formation of these structures. The modern microbialites of Laguna Negra in northeastern Argentina [1] offer an opportunity to examine the biological and geochemical differences among microbialites displaying distinct morphological diversity in a single setting. Three broad types of microbialites are found at this site: oncoids, stromatolites, and laminar crusts. Each of these types of microbialites are associated with visually distinct microbial mats. We have examined the structural and isotopic composition of lipid biomarkers from each of these microbialite types, and their associated mats. Sterol profiles detected from microbial mats and microbialites showed abundant C27 to C29 sterols and indicate that primary producers are dominated by algae. Decreased abundances of more labile unsaturated fatty acids relative to more recalcitrant saturated fatty acids were observed in microbialites compared to extant mats suggesting preferential loss of these compounds during diagenesis. Among the three different microbialite morphologies, no statistically discernable differences in biomarker profiles were detected. This implies that morphological changes are due to either geochemical/physical changes across the zone of microbialite formation or changes in community structure that are not observable in the present biomarker set. [1] Gomez et al. (2014) Palaios 29, 233-249

Evolutionary Novelty in a Butterfly Wing Pattern through Enhancer Shuffling

PubMed Central

Pardo-Diaz, Carolina; Hanly, Joseph J.; Martin, Simon H.; Mallet, James; Dasmahapatra, Kanchon K.; Salazar, Camilo; Joron, Mathieu; Nadeau, Nicola; McMillan, W. Owen; Jiggins, Chris D.

2016-01-01

An important goal in evolutionary biology is to understand the genetic changes underlying novel morphological structures. We investigated the origins of a complex wing pattern found among Amazonian Heliconius butterflies. Genome sequence data from 142 individuals across 17 species identified narrow regions associated with two distinct red colour pattern elements, dennis and ray. We hypothesise that these modules in non-coding sequence represent distinct cis-regulatory loci that control expression of the transcription factor optix, which in turn controls red pattern variation across Heliconius. Phylogenetic analysis of the two elements demonstrated that they have distinct evolutionary histories and that novel adaptive morphological variation was created by shuffling these cis-regulatory modules through recombination between divergent lineages. In addition, recombination of modules into different combinations within species further contributes to diversity. Analysis of the timing of diversification in these two regions supports the hypothesis of introgression moving regulatory modules between species, rather than shared ancestral variation. The dennis phenotype introgressed into Heliconius melpomene at about the same time that ray originated in this group, while ray introgressed back into H. elevatus much more recently. We show that shuffling of existing enhancer elements both within and between species provides a mechanism for rapid diversification and generation of novel morphological combinations during adaptive radiation. PMID:26771987

Evolutionary Novelty in a Butterfly Wing Pattern through Enhancer Shuffling.

PubMed

Wallbank, Richard W R; Baxter, Simon W; Pardo-Diaz, Carolina; Hanly, Joseph J; Martin, Simon H; Mallet, James; Dasmahapatra, Kanchon K; Salazar, Camilo; Joron, Mathieu; Nadeau, Nicola; McMillan, W Owen; Jiggins, Chris D

2016-01-01

An important goal in evolutionary biology is to understand the genetic changes underlying novel morphological structures. We investigated the origins of a complex wing pattern found among Amazonian Heliconius butterflies. Genome sequence data from 142 individuals across 17 species identified narrow regions associated with two distinct red colour pattern elements, dennis and ray. We hypothesise that these modules in non-coding sequence represent distinct cis-regulatory loci that control expression of the transcription factor optix, which in turn controls red pattern variation across Heliconius. Phylogenetic analysis of the two elements demonstrated that they have distinct evolutionary histories and that novel adaptive morphological variation was created by shuffling these cis-regulatory modules through recombination between divergent lineages. In addition, recombination of modules into different combinations within species further contributes to diversity. Analysis of the timing of diversification in these two regions supports the hypothesis of introgression moving regulatory modules between species, rather than shared ancestral variation. The dennis phenotype introgressed into Heliconius melpomene at about the same time that ray originated in this group, while ray introgressed back into H. elevatus much more recently. We show that shuffling of existing enhancer elements both within and between species provides a mechanism for rapid diversification and generation of novel morphological combinations during adaptive radiation.

Morphological and molecular dissection of wild rices from eastern India suggests distinct speciation between O. rufipogon and O. nivara populations.

PubMed

Samal, Rashmita; Roy, Pritesh Sundar; Sahoo, Auromira; Kar, Meera Kumari; Patra, Bhaskar Chandra; Marndi, Bishnu Charan; Gundimeda, Jwala Narasimha Rao

2018-02-09

The inter relationships between the two progenitors is interesting as both wild relatives are known to be the great untapped gene reservoirs. The debate continues on granting a separate species status to Oryza nivara. The present study was conducted on populations of Oryza rufipogon and Oryza nivara from Eastern India employing morphological and molecular characteristics. The cluster analysis of the data on morphological traits could clearly classify the two wild forms into two separate discrete groups without any overlaps i.e. lack of intermediate forms, suggesting the non-sympatric existence of the wild forms. Amplification of hyper variable regions of the genome could reveal 144 alleles suggesting high genetic diversity values (average He = 0.566). Moreover, with 42.37% of uncommon alleles between the two wild relatives, the molecular variance analysis (AMOVA) could detect only 21% of total variation (p < 0.001) among them and rest 59% was within them. The population structure analysis clearly classified these two wild populations into two distinct sub-populations (K = 2) without any overlaps i.e. lack of intermediate forms, suggesting the non-sympatric existence of the wild forms. Clear differentiation into two distinct groups indicates that O. rufipogon and O. nivara could be treated as two different species.

Spatial structure of morphological and neutral genetic variation in Brook Trout

USGS Publications Warehouse

Kazyak, David C.; Hilderbrand, Robert H.; Keller, Stephen R.; Colaw, Mark C.; Holloway, Amanda E.; Morgan, Raymond P.; King, Timothy L.

2015-01-01

Brook Trout Salvelinus fontinalis exhibit exceptional levels of life history variation, remarkable genetic variability, and fine-scale population structure. In many cases, neighboring populations may be highly differentiated from one another to an extent that is comparable with species-level distinctions in other taxa. Although genetic samples have been collected from hundreds of populations and tens of thousands of individuals, little is known about whether differentiation at neutral markers reflects phenotypic differences among Brook Trout populations. We compared differentiation in morphology and neutral molecular markers among populations from four geographically proximate locations (all within 24 km) to examine how genetic diversity covaries with morphology. We found significant differences among and/or within streams for all three morphological axes examined and identified the source stream of many individuals based on morphology (52.3% classification efficiency). Although molecular and morphological differentiation among streams ranged considerably (mean pairwise FST: 0.023–0.264; pairwise PST: 0.000–0.339), the two measures were not significantly correlated. While in some cases morphological characters appear to have diverged to a greater extent than expected by neutral genetic drift, many traits were conserved to a greater extent than were neutral genetic markers. Thus, while Brook Trout exhibit fine-scale spatial patterns in both morphology and neutral genetic diversity, these types of biological variabilities are being structured by different ecological and evolutionary processes. The relative influences of genetic drift versus selection and phenotypic plasticity in shaping morphology appear to vary among populations occupying nearby streams.

Ordered to isotropic morphology transition in pattern-directed dewetting of polymer thin films on substrates with different feature heights.

PubMed

Roy, Sudeshna; Mukherjee, Rabibrata

2012-10-24

Controlled dewetting of a thin polymer film on a topographically patterned substrate is an interesting approach for aligning isotropic dewetted structures. In this article, we investigate the influence of substrate feature height (H(S)) on the dewetting pathway and final pattern morphology by studying the dewetting of polystyrene (PS) thin films on grating substrates with identical periodicity (λ(P) = 1.5 μm), but H(S) varying between 10 nm and 120 nm. We identify four distinct categories of final dewetted morphology, with different extent of ordering: (1) array of aligned droplets (H(S) ≈ 120 nm); (2) aligned undulating ribbons (H(S) ≈ 70-100 nm); (3) multilength scale structures with coexisting large droplets uncorrelated to the substrate and smaller droplets/ribbons aligned along the stripes (H(S) ≈ 40-60 nm); and (4) large droplets completely uncorrelated to the substrate (H(S) < 25 nm). The distinct morphologies across the categories are attributed to two major factors: (a) whether the as-cast film is continuous (H(S)≤ 80 nm) or discontinuous (H(S)≥ 100 nm) and (b) in case of a continuous film, whether the film ruptures along each substrate stripe (H(S)≥ 70 nm) or with nucleation of random holes that are not correlated to the substrate features (H(S)≤ 60 nm). While the ranges of H(S) values indicated in the parentheses are valid for PS films with an equivalent thickness (h(E)) ≈ 50.3 nm on a flat substrate, a change in h(E) merely alters the cut-off values of H(S), as the final dewetted morphologies and transition across categories remain generically unaltered. We finally show that the structures obtained by dewetting on different H(S) substrates exhibits different levels of hydrophobicity because of combined spatial variation of chemical and topographic contrast along the surface. Thus, the work reported in this article can find potential application in fabricating surfaces with controlled wettability.

Crystal morphology variation in inkjet-printed organic materials

NASA Astrophysics Data System (ADS)

Ihnen, Andrew C.; Petrock, Anne M.; Chou, Tsengming; Samuels, Phillip J.; Fuchs, Brian E.; Lee, Woo Y.

2011-11-01

The recent commercialization of piezoelectric-based drop-on-demand inkjet printers provides an additive processing platform for producing and micropatterning organic crystal structures. We report an inkjet printing approach where macro- and nano-scale energetic composites composed of cyclotrimethylenetrinitramine (RDX) crystals dispersed in a cellulose acetate butyrate (CAB) matrix are produced by direct phase transformation from organic solvent-based all-liquid inks. The characterization of printed composites illustrates distinct morphological changes dependent on ink deposition parameters. When 10 pL ink droplets rapidly formed a liquid pool, a coffee ring structure containing dendritic RDX crystals was produced. By increasing the substrate temperature, and consequently the evaporation rate of the pooled ink, the coffee ring structure was mitigated and shorter dendrites from up to ∼1 to 0.2 mm with closer arm spacing from ∼15 to 1 μm were produced. When the nucleation and growth of RDX and CAB were confined within the evaporating droplets, a granular structure containing nanoscale RDX crystals was produced. The results suggest that evaporation rate and microfluidic droplet confinement can effectively be used to tailor the morphology of inkjet-printed energetic composites.

Asynchronous evolution of physiology and morphology in Anolis lizards.

PubMed

Hertz, Paul E; Arima, Yuzo; Harrison, Alexis; Huey, Raymond B; Losos, Jonathan B; Glor, Richard E

2013-07-01

Species-rich adaptive radiations typically diversify along several distinct ecological axes, each characterized by morphological, physiological, and behavioral adaptations. We test here whether different types of adaptive traits share similar patterns of evolution within a radiation by investigating patterns of evolution of morphological traits associated with microhabitat specialization and of physiological traits associated with thermal biology in Anolis lizards. Previous studies of anoles suggest that close relatives share the same "structural niche" (i.e., use the same types of perches) and are similar in body size and shape, but live in different "climatic niches" (i.e., use habitats with different insolation and temperature profiles). Because morphology is closely tied to structural niche and field active body temperatures are tied to climatic niches in Anolis, we expected phylogenetic analyses to show that morphology is more evolutionarily conservative than thermal physiology. In support of this hypothesis, we find (1) that thermal biology exhibits more divergence among recently diverged Anolis taxa than does morphology; and (2) diversification of thermal biology among all species often follows diversification in morphology. These conclusions are remarkably consistent with predictions made by anole biologists in the 1960s and 1970s. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Nanomechanical properties of distinct fibrillar polymorphs of the protein α-synuclein

PubMed Central

Makky, Ali; Bousset, Luc; Polesel-Maris, Jérôme; Melki, Ronald

2016-01-01

Alpha-synuclein (α-Syn) is a small presynaptic protein of 140 amino acids. Its pathologic intracellular aggregation within the central nervous system yields protein fibrillar inclusions named Lewy bodies that are the hallmarks of Parkinson’s disease (PD). In solution, pure α-Syn adopts an intrinsically disordered structure and assembles into fibrils that exhibit considerable morphological heterogeneity depending on their assembly conditions. We recently established tightly controlled experimental conditions allowing the assembly of α-Syn into highly homogeneous and pure polymorphs. The latter exhibited differences in their shape, their structure but also in their functional properties. We have conducted an AFM study at high resolution and performed a statistical analysis of fibrillar α-Syn shape and thermal fluctuations to calculate the persistence length to further assess the nanomechanical properties of α-Syn polymorphs. Herein, we demonstrated quantitatively that distinct polymorphs made of the same protein (wild-type α-Syn) show significant differences in their morphology (height, width and periodicity) and physical properties (persistence length, bending rigidity and axial Young’s modulus). PMID:27901068

Influences of MAA on the porous morphology of P(St-MAA) latex particles produced by batch soap-free emulsion polymerization followed by stepwise alkali/acid post-treatment.

PubMed

Deng, Wei; Li, Ronglong; Zhang, Mengjun; Gong, Lixiang; Kan, Chengyou

2010-09-01

Soap-free P(St-MAA) latex particles with variable styrene (St)/methacrylic acid (MAA) ratio were synthesized by batch emulsion copolymerization at 70 degrees C for 7h, and the particles with porous structure were obtained after stepwise alkali/acid post-treatment. The effects of MAA amount on the particle morphologies after the alkali and the stepwise alkali/acid post-treatments were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Results indicated that the alkali-treated latex particles showed anomalous structure with rough surface, and no hollow was clearly identified inside them. When these alkali-treated particles were further treated with acid solution, the particle surface became much smoother, and porous morphology appeared. It was found that when the MAA amount was less than or equal to 4mol%, no obvious morphological variation was observed; while the latex particles showed clearly porous structure as the MAA amount increased to 6mol%; with the further increase of MAA amount to 8mol%, the pore size decreased distinctly. Copyright 2010 Elsevier Inc. All rights reserved.

Hard X-ray Microscopic Images of the Human Hair

NASA Astrophysics Data System (ADS)

Goo, Jawoong; Jeon, Soo Young; Oh, Tak Heon; Hong, Seung Phil; Yon, Hwa Shik; Lee, Won-Soo

2007-01-01

The better visualization of the human organs or internal structure is challenging to the physicist and physicians. It can lead to more understanding of the morphology, pathophysiology and the diagnosis. Conventionally used methods to investigate cells or architectures, show limited value due to sample processing procedures and lower resolution. In this respect, Zernike type phase contrast hard x-ray microscopy using 6.95keV photon energy has advantages. We investigated hair fibers of the normal healthy persons. Coherence based phase contrast images revealed three distinct structures of hair, medulla, cortex, and cuticular layer. Some different detailed characters of each sample were noted. And further details would be shown and these results would be utilized as basic data of morphologic study of human hair.

How discordant morphological and molecular evolution among microorganisms can revise our notions of biodiversity on earth

PubMed Central

Lahr, Daniel J. G.; Laughinghouse, H. Dail; Oliverio, Angela; Gao, Feng; Katz, Laura A.

2014-01-01

Microscopy has revealed a tremendous diversity of bacterial and eukaryotic forms. More recent molecular analyses show discordance in estimates of biodiversity based on morphological analyses. Moreover, phylogenetic analyses of the diversity of microbial forms have revealed evidence of convergence at scales as large as interdomain – i.e. convergent forms shared between bacteria and eukaryotes. Here, we highlight examples of such discordance, focusing on exemplary lineages such as testate amoebae, ciliates and cyanobacteria, which have long histories of morphological study. We discuss examples in two categories: 1) morphologically identical (or highly similar) individuals that are genetically distinct and 2) morphologically distinct individuals that are genetically distinct. We argue that hypotheses about discordance can be tested using the concept of neutral morphologies, or more broadly neutral phenotypes, as a null hypothesis. PMID:25156897

Morphometric analysis of astrocytes in brainstem respiratory regions.

PubMed

Sheikhbahaei, Shahriar; Morris, Brian; Collina, Jared; Anjum, Sommer; Znati, Sami; Gamarra, Julio; Zhang, Ruli; Gourine, Alexander V; Smith, Jeffrey C

2018-06-11

Astrocytes, the most abundant and structurally complex glial cells of the central nervous system, are proposed to play an important role in modulating the activities of neuronal networks, including respiratory rhythm-generating circuits of the preBötzinger complex (preBötC) located in the ventrolateral medulla of the brainstem. However, structural properties of astrocytes residing within different brainstem regions are unknown. In this study astrocytes in the preBötC, an intermediate reticular formation (IRF) region with respiratory-related function, and a region of the nucleus tractus solitarius (NTS) in adult rats were reconstructed and their morphological features were compared. Detailed morphological analysis revealed that preBötC astrocytes are structurally more complex than those residing within the functionally distinct neighboring IRF region, or the NTS, located at the dorsal aspect of the medulla oblongata. Structural analyses of the brainstem microvasculature indicated no significant regional differences in vascular properties. We hypothesize that high morphological complexity of preBötC astrocytes reflects their functional role in providing structural/metabolic support and modulation of the key neuronal circuits essential for breathing, as well as constraints imposed by arrangements of associated neurons and/or other local structural features of the brainstem parenchyma. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Large Impact Features on Icy Galilean Satellites

NASA Technical Reports Server (NTRS)

Moore, J. M.; Schenk, P. M.; Korycansky, D. G.

2017-01-01

Impact crater morphology can be a very useful tool for probing planetary interiors, but nowhere in the solar system is a greater variety of crater morphologies observed (Fig. 1) than on the large icy Galilean satellites Ganymede and Callisto [e.g., 1- 3]. As on the rocky terrestrial planets, impact crater morphology becomes more complex with increasing size on these satellites. With increasing size, however, these same craters become less like their counterparts on the rocky planets. Several impact landforms and structures (multiring furrows, palimpsests, and central domes, for example), have no obvious analogs on any other planets. Further, several studies [e.g., 4-6] have drawn attention to impact landforms on Europa which are unusual, even by Galilean satellite standards. These radical differences in morphology suggest that impact into icy lithospheres that are mechanically distinct from silicate lithospheres may be responsible. As such, large impact structures may be important probes of the interiors of these bodies over time [e.g., 7]. The first goal of this work is to integrate and correlate the detailed morphologic and morphometric measurements and observations of craters on icy Galilean satellites [e.g., 4, 8-12] with new detailed mapping of these structures from Galileo high-resolution images. As a result, we put forward a revised crater taxonomy for Ganymede and Callisto in order to simplify the nonuniform impact crater nomenclature cluttering the literature. We develop and present an integrated model for the development of these unusual crater morphologies and their implications for the thermal evolution of these bodies.

Towards revealing the structure of bacterial inclusion bodies

PubMed Central

2009-01-01

Protein aggregation is a widely observed phenomenon in human diseases, biopharmaceutical production, and biological research. Protein aggregates are generally classified as highly ordered, such as amyloid fibrils, or amorphous, such as bacterial inclusion bodies. Amyloid fibrils are elongated filaments with diameters of 6–12 nm, they are comprised of residue-specific cross-β structure, and display characteristic properties, such as binding with amyloid-specific dyes. Amyloid fibrils are associated with dozens of human pathological conditions, including Alzheimer disease and prion diseases. Distinguished from amyloid fibrils, bacterial inclusion bodies display apparent amorphous morphology. Inclusion bodies are formed during high-level recombinant protein production, and formation of inclusion bodies is a major concern in biotechnology. Despite of the distinctive morphological difference, bacterial inclusion bodies have been found to have some amyloid-like properties, suggesting that they might contain structures similar to amyloid-like fibrils. Recent structural data further support this hypothesis, and this review summarizes the latest progress towards revealing the structural details of bacterial inclusion bodies. PMID:19806034

Towards revealing the structure of bacterial inclusion bodies.

PubMed

Wang, Lei

2009-01-01

Protein aggregation is a widely observed phenomenon in human diseases, biopharmaceutical production, and biological research. Protein aggregates are generally classified as highly ordered, such as amyloid fibrils, or amorphous, such as bacterial inclusion bodies. Amyloid fibrils are elongated filaments with diameters of 6-12 nm, they are comprised of residue-specific cross-beta structure, and display characteristic properties, such as binding with amyloid-specific dyes. Amyloid fibrils are associated with dozens of human pathological conditions, including Alzheimer disease and prion diseases. Distinguished from amyloid fibrils, bacterial inclusion bodies display apparent amorphous morphology. Inclusion bodies are formed during high-level recombinant protein production, and formation of inclusion bodies is a major concern in biotechnology. Despite of the distinctive morphological difference, bacterial inclusion bodies have been found to have some amyloid-like properties, suggesting that they might contain structures similar to amyloid-like fibrils. Recent structural data further support this hypothesis, and this review summarizes the latest progress towards revealing the structural details of bacterial inclusion bodies.

Morphology and Structures of Nearby Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Seo, Mira; Ann, HongBae

2015-08-01

We performed an analysis of the structure of nearby dwarf galaxies based on a 2-dimensional decomposition of galaxy images using GALFIT. The present sample consists of ~1,100 dwarf galaxies with redshift less than z = 0.01, which is is derived from the morphology catalog of the Visually classified galaxies in the local universe (Ann, Seo, and Ha 2015). In this catalog, dwarf galaxies are divided into 5 subtypes: dS0, dE, dSph, dEbc, dEblue with distinction of the presence of nucleation in dE, dSph, and dS0. We found that dSph and dEblue galaxies are fainter than other subtypes of dwarf galaxies. In most cases, single component, represented by the Sersic profile with n=1~1.5, well describes the luminosity distribution of dwarf galaxies in the present sample. However, a significant fraction of dS0, dEbc, and dEbue galaxies show sub-structures such as spiral arms and rings. We will discuss the morphology dependent evolutionary history of the local dwarf galaxies.

Morphology of size-selected Ptn clusters on CeO2(111)

NASA Astrophysics Data System (ADS)

Shahed, Syed Mohammad Fakruddin; Beniya, Atsushi; Hirata, Hirohito; Watanabe, Yoshihide

2018-03-01

Supported Pt catalysts and ceria are well known for their application in automotive exhaust catalysts. Size-selected Pt clusters supported on a CeO2(111) surface exhibit distinct physical and chemical properties. We investigated the morphology of the size-selected Ptn (n = 5-13) clusters on a CeO2(111) surface using scanning tunneling microscopy at room temperature. Ptn clusters prefer a two-dimensional morphology for n = 5 and a three-dimensional (3D) morphology for n ≥ 6. We further observed the preference for a 3D tri-layer structure when n ≥ 10. For each cluster size, we quantitatively estimated the relative fraction of the clusters for each type of morphology. Size-dependent morphology of the Ptn clusters on the CeO2(111) surface was attributed to the Pt-Pt interaction in the cluster and the Pt-O interaction between the cluster and CeO2(111) surface. The results obtained herein provide a clear understanding of the size-dependent morphology of the Ptn clusters on a CeO2(111) surface.

Morphology of size-selected Ptn clusters on CeO2(111).

PubMed

Shahed, Syed Mohammad Fakruddin; Beniya, Atsushi; Hirata, Hirohito; Watanabe, Yoshihide

2018-03-21

Supported Pt catalysts and ceria are well known for their application in automotive exhaust catalysts. Size-selected Pt clusters supported on a CeO 2 (111) surface exhibit distinct physical and chemical properties. We investigated the morphology of the size-selected Pt n (n = 5-13) clusters on a CeO 2 (111) surface using scanning tunneling microscopy at room temperature. Pt n clusters prefer a two-dimensional morphology for n = 5 and a three-dimensional (3D) morphology for n ≥ 6. We further observed the preference for a 3D tri-layer structure when n ≥ 10. For each cluster size, we quantitatively estimated the relative fraction of the clusters for each type of morphology. Size-dependent morphology of the Pt n clusters on the CeO 2 (111) surface was attributed to the Pt-Pt interaction in the cluster and the Pt-O interaction between the cluster and CeO 2 (111) surface. The results obtained herein provide a clear understanding of the size-dependent morphology of the Pt n clusters on a CeO 2 (111) surface.

Sexual selection and the evolution of genital shape and complexity in water striders.

PubMed

Rowe, Locke; Arnqvist, Göran

2012-01-01

Animal genitalia show two striking but incompletely understood evolutionary trends: a great evolutionary divergence in the shape of genitalic structures, and characteristic structural complexity. Both features are thought to result from sexual selection, but explicit comparative tests are hampered by the fact that it is difficult to quantify both morphological complexity and divergence in shape. We undertake a comparative study of multiple nongenitalic and male genital traits in a clade of 15 water strider species to quantify complexity and shape divergence. We show that genital structures are more complex and their shape more divergent among species than nongenital traits. Further, intromittent genital traits are more complex and have evolved more divergently than nonintromittent genital traits. More importantly, shape and complexity of nonintromittent genital traits show correlated evolution with indices of premating sexual selection and intromittent genital traits with postmating sexual selection, suggesting that the evolution of different components of genital morphology are shaped independently by distinct forms of sexual selection. Our quantitative results provide direct comparative support for the hypothesis that sexual selection is associated with morphological complexity in genitalic traits and highlight the importance of quantifying morphological shape and complexity, rather than size in studies of genital evolution. © 2011 The Author(s). Evolution © 2011 The Society for the Study of Evolution.

The Production of Nominal and Verbal Inflection in an Agglutinative Language: Evidence from Hungarian

PubMed Central

Peckham, Don; Szanka, Szilvia; Gazso, Dorottya; Lovassy, Noemi; Ullman, Michael T.

2015-01-01

The contrast between regular and irregular inflectional morphology has been useful in investigating the functional and neural architecture of language. However, most studies have examined the regular/irregular distinction in non-agglutinative Indo-European languages (primarily English) with relatively simple morphology. Additionally, the majority of research has focused on verbal rather than nominal inflectional morphology. The present study attempts to address these gaps by introducing both plural and past tense production tasks in Hungarian, an agglutinative non-Indo-European language with complex morphology. Here we report results on these tasks from healthy Hungarian native-speaking adults, in whom we examine regular and irregular nominal and verbal inflection in a within-subjects design. Regular and irregular nouns and verbs were stem on frequency, word length, and phonological structure, and both accuracy and response times were acquired. The results revealed that the regular/irregular contrast yields similar patterns in Hungarian, for both nominal and verbal inflection, as in previous studies of non-agglutinative Indo-European languages: the production of irregular inflected forms was both less accurate and slower than of regular forms, both for plural and past-tense inflection. The results replicate and extend previous findings to an agglutinative language with complex morphology. Together with previous studies, the evidence suggests that the regular/irregular distinction yields a basic behavioral pattern that holds across language families and linguistic typologies. Finally, the study sets the stage for further research examining the neurocognitive substrates of regular and irregular morphology in an agglutinative non-Indo-European language. PMID:25769039

Hydrocarbon-Based Polymer Electrolyte Membranes: Importance of Morphology on Ion Transport and Membrane Stability.

PubMed

Shin, Dong Won; Guiver, Michael D; Lee, Young Moo

2017-03-22

A fundamental understanding of polymer microstructure is important in order to design novel polymer electrolyte membranes (PEMs) with excellent electrochemical performance and stabilities. Hydrocarbon-based polymers have distinct microstructure according to their chemical structure. The ionic clusters and/or channels play a critical role in PEMs, affecting ion conductivity and water transport, especially at medium temperature and low relative humidity (RH). In addition, physical properties such as water uptake and dimensional swelling behavior depend strongly on polymer morphology. Over the past few decades, much research has focused on the synthetic development and microstructural characterization of hydrocarbon-based PEM materials. Furthermore, blends, composites, pressing, shear field, electrical field, surface modification, and cross-linking have also been shown to be effective approaches to obtain/maintain well-defined PEM microstructure. This review summarizes recent work on developments in advanced PEMs with various chemical structures and architecture and the resulting polymer microstructures and morphologies that arise for potential application in fuel cell, lithium ion battery, redox flow battery, actuators, and electrodialysis.

Naphtho[2,1-b:3,4-b']dithiophene-based bulk heterojunction solar cells: how molecular structure influences nanoscale morphology and photovoltaic properties.

PubMed

Kim, Yu Jin; Cheon, Ye Rim; Back, Jang Yeol; Kim, Yun-Hi; Chung, Dae Sung; Park, Chan Eon

2014-11-10

Organic bulk heterojunction photovoltaic devices based on a series of three naphtho[2,1-b:3,4-b']dithiophene (NDT) derivatives blended with phenyl-C71-butyric acid methyl ester were studied. These three derivatives, which have NDT units with various thiophene-chain lengths, were employed as the donor polymers. The influence of their molecular structures on the correlation between their solar-cell performances and their degree of crystallization was assessed. The grazing-incidence angle X-ray diffraction and atomic force microscopy results showed that the three derivatives exhibit three distinct nanoscale morphologies. We correlated these morphologies with the device physics by determining the J-V characteristics and the hole and electron mobilities of the devices. On the basis of our results, we propose new rules for the design of future generations of NDT-based polymers for use in bulk heterojunction solar cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Psychiatric risk factor ANK3/Ankyrin-G nanodomains regulate the structure and function of glutamatergic synapses

PubMed Central

Smith, Katharine R.; Kopeikina, Katherine J.; Fawcett-Patel, Jessica M.; Leaderbrand, Katherine; Gao, Ruoqi; Schürmann, Britta; Myczek, Kristoffer; Radulovic, Jelena; Swanson, Geoffrey T.; Penzes, Peter

2014-01-01

Summary Recent evidence implicates glutamatergic synapses as key pathogenic sites in psychiatric disorders. Common and rare variants in the ANK3 gene, encoding ankyrin-G, have been associated with bipolar disorder, schizophrenia, and autism. Here we demonstrate that ankyrin-G is integral to AMPAR-mediated synaptic transmission and maintenance of spine morphology. Using super-resolution microscopy we find that ankyrin-G forms distinct nanodomain structures within the spine head and neck. At these sites, it modulates mushroom spine structure and function, likely as a perisynaptic scaffold and barrier within the spine neck. Neuronal activity promotes ankyrin-G accumulation in distinct spine subdomains, where it differentially regulates NMDA receptor-dependent plasticity. These data implicate subsynaptic nanodomains containing a major psychiatric risk molecule, ankyrin-G, as having location-specific functions, and opens directions for basic and translational investigation of psychiatric risk molecules. PMID:25374361

Distinct Photovoltaic Performance of Hierarchical Nanostructures Self-Assembled from Multiblock Copolymers.

PubMed

Xu, Zhanwen; Lin, Jiaping; Zhang, Liangshun; Wang, Liquan; Wang, Gengchao; Tian, Xiaohui; Jiang, Tao

2018-06-14

We applied a multi-scale approach coupling dissipative particle dynamics method with a drift-diffusion model to elucidate the photovoltaic properties of multiblock copolymers consisting of alternating electron donor and acceptor blocks. A series of hierarchical lamellae-in-lamellar structures were obtained from the self-assembly of the multiblock copolymers. A distinct improvement in photovoltaic performance upon the morphology transformation from lamella to lamellae-in-lamella was observed. The hierarchical lamellae-in-lamellar structures significantly enhanced exciton dissociation and charge carrier transport, which consequently contributed to the improved photovoltaic performance. Based on our theoretical calculations, the hierarchical nanostructures can achieve a much enhanced energy conversion efficiency, improved by around 25% compared with that of general ones, through structure modulation on number and size of the small-length-scale domains. Our findings are supported by recent experimental evidence and yield guidelines for designing hierarchical materials with improved photovoltaic properties.

Spontaneous Epithelioid Hemangiosarcoma in a Rhesus Monkey (Macaca mulatta)

PubMed Central

Tsuchiya, Takayuki; Gray, Tasha L; Gatto, Nicholas T; Forest, Thomas; Machotka, Sam V; Troth, Sean P; Prahalada, Srinivasa

2014-01-01

Epithelioid hemangiosarcoma is a rare malignant endothelial neoplasia with a unique, predominantly epithelioid morphology. A 4-y-old rhesus monkey from our laboratory had multiple neoplastic nodules in a digit, limb skin, hindlimb muscle, and visceral organs including lung, heart, and brain. The nodules were composed of pleomorphic, polygonal, epithelioid, neoplastic cells that were arranged in sheets, nests, and cords and supported by variably dense fibrovascular connective tissue. The morphologic features of this tumor were predominantly epithelioid. However, some regions contained cystic spaces, clefts, and channel-like structures, all of which were lined with morphologically distinct neoplastic endothelial cells. These neoplastic cells, with or without epithelioid morphology, were positive immunohistochemically for CD31, factor VIII-related antigen, and vimentin. The presence of multiple metastatic nodules, high mitotic rate, and extensive Ki67-positive staining were consistent with malignancy. This report is the first description of epithelioid hemangiosarcoma in a rhesus monkey. PMID:25296017

Spontaneous epithelioid hemangiosarcoma in a rhesus monkey (Macaca mulatta).

PubMed

Tsuchiya, Takayuki; Gray, Tasha L; Gatto, Nicholas T; Forest, Thomas; Machotka, Sam V; Troth, Sean P; Prahalada, Srinivasa

2014-08-01

Epithelioid hemangiosarcoma is a rare malignant endothelial neoplasia with a unique, predominantly epithelioid morphology. A 4-y-old rhesus monkey from our laboratory had multiple neoplastic nodules in a digit, limb skin, hindlimb muscle, and visceral organs including lung, heart, and brain. The nodules were composed of pleomorphic, polygonal, epithelioid, neoplastic cells that were arranged in sheets, nests, and cords and supported by variably dense fibrovascular connective tissue. The morphologic features of this tumor were predominantly epithelioid. However, some regions contained cystic spaces, clefts, and channel-like structures, all of which were lined with morphologically distinct neoplastic endothelial cells. These neoplastic cells, with or without epithelioid morphology, were positive immunohistochemically for CD31, factor VIII-related antigen, and vimentin. The presence of multiple metastatic nodules, high mitotic rate, and extensive Ki67-positive staining were consistent with malignancy. This report is the first description of epithelioid hemangiosarcoma in a rhesus monkey.

Groundwater sapping channels: Summary of effects of experiments with varied stratigraphy

NASA Technical Reports Server (NTRS)

Kochel, R. Craig; Simmons, David W.

1987-01-01

Experiments in the recirculating flume sapping box have modeled valley formation by groundwater sapping processes in a number of settings. The effects of the following parameters on sapping channel morphology were examined: surface slope; stratigraphic variations in permeability cohesion and dip; and structure of joints and dikes. These kinds of modeling experiments are particularly good for: testing concepts; developing a suite of distinctive morphologies and morphometries indicative of sapping; helping to relate process to morphology; and providing data necessary to assess the relative importance of runoff, sapping, and mass wasting processes on channel development. The observations from the flume systems can be used to help interpret features observed in terrestrial and Martian settings where sapping processes are thought to have played an important role in the development of valley networks.

Mechanical vibrations from tadpoles' flapping tails transform salamander's carnivorous morphology.

PubMed

Michimae, Hirofumi; Nishimura, Kinya; Wakahara, Masami

2005-03-22

Some prey or predator organisms exhibit striking rapid morphological plastic changes with distinct morphology under the condition of predator or prey presence. Remote chemicals propagating from the inducing agents are the prevalent induction cues for most examples of induction of distinct morphs. Sonic and visual cues, as well as chemical cues, are known as triggers for induction of behavioural plasticity. Here we show that hydraulic vibration originating from flapping tails of anuran tadpoles is a key cue in relation to induction of a distinct carnivorous morphology, a broad-headed morph, in larval salamander Hynobius retardatus, which is able to efficiently capture and handle prey. This result was further supported by the fact that simple mechanical vibrations of tail-like vinyl fins were able to induce the morph without any biological cues. Induction of the morph triggered by hydraulic vibration provides a novel concept for understanding the proximate mechanisms of induction of morphological changes.

On the Origins of Starburst and Poststarburst Galaxies in Nearby Clusters

NASA Astrophysics Data System (ADS)

Caldwell, Nelson; Rose, James A.; Dendy, Kristi

1999-01-01

Hubble Space Telescope (HST) Wide Field Planetary Camera 2 images in B (F450W) and I (F814W) have been obtained for three starburst (SB) and two poststarburst (PSB) galaxies in the Coma Cluster and for three such galaxies in the cluster DC 048-52. V (F555W) and I images for an additional PSB galaxy in Coma have been extracted from the HST archive. Six of these galaxies were previously classified as E/S0 on the basis of ground-based images, two as Sa, and the other as an irregular. The HST images reveal these SB/PSB galaxies to be heterogeneous in morphology. Nevertheless, a common theme is that many of them, especially the SB galaxies, tend to have centralized spiral structure that appears simply as a bright ``bulge'' on ground-based images. In addition, while some PSB galaxies exhibit distinct spiral structure, on the whole they have smoother morphologies than the SB galaxies. The morphologies and luminosity profiles are generally consistent with substantial starbursts, in the form of centralized spiral structure (the SB galaxies), that fade into smoother morphologies (the PSB galaxies), with lingering spectroscopic evidence for past central starbursts. An important point is that the PSB galaxies retain disks; i.e., they have not evolved into spheroidal systems. While the morphologies revealed in the HST images are heterogeneous, and thus may not fit well into a single picture, we see evidence in several cases that the morphologies and centralized star formation have been driven by external tidal perturbations. We discuss several physical mechanisms for inducing star formation in cluster galaxies with a view toward explaining the particular morphologies seen in the HST images.

Variation in the shape and mechanical performance of the lower jaws in ceratopsid dinosaurs (Ornithischia, Ceratopsia).

PubMed

Maiorino, Leonardo; Farke, Andrew A; Kotsakis, Tassos; Teresi, Luciano; Piras, Paolo

2015-11-01

Ceratopsidae represents a group of quadrupedal herbivorous dinosaurs that inhabited western North America and eastern Asia during the Late Cretaceous. Although horns and frills of the cranium are highly variable across species, the lower jaw historically has been considered to be relatively conservative in morphology. Here, the lower jaws from 58 specimens representing 21 ceratopsoid taxa were sampled, using geometric morphometrics and 2D finite element analysis (FEA) to explore differences in morphology and mechanical performance across Ceratopsoidea (the clade including Ceratopsidae, Turanoceratops and Zuniceratops). Principal component analyses and non-parametric permuted manovas highlight Triceratopsini as a morphologically distinct clade within the sample. A relatively robust and elongate dentary, a larger and more elongated coronoid process, and a small and dorso-ventrally compressed angular characterize this clade, as well as the absolutely larger size. By contrast, non-triceratopsin chasmosaurines, Centrosaurini and Pachyrhinosaurini have similar morphologies to each other. Zuniceratops and Avaceratops are distinct from other taxa. No differences in size between Pachyrhinosaurini and Centrosaurini are recovered using non-parametric permuted anovas. Structural performance, as evaluated using a 2D FEA, is similar across all groups as measured by overall stress, with the exception of Triceratopsini. Shape, size and stress are phylogenetically constrained. A longer dentary as well as a long coronoid process result in a lower jaw that is reconstructed as relatively much more stressed in triceratopsins. © 2015 Anatomical Society.

Strike-Slip Faulting Processes on Ganymede: Global Morphological Mapping and Structural Interpretation of Grooved and Transitional Terrains

NASA Astrophysics Data System (ADS)

Burkhard, L. M.; Cameron, M. E.; Smith-Konter, B. R.; Seifert, F.; Pappalardo, R. T.; Collins, G. C.

2015-12-01

Ganymede's fractured surface reveals many large-scale, morphologically distinct regions of inferred distributed shear and strike-slip faulting that may be important to the structural development of its surface and in the transition from dark to light (grooved) materials. To better understand the role of strike-slip tectonism in shaping Ganymede's complex icy surface, we perform a detailed mapping of key examples of strike-slip morphologies (i.e., en echelon structures, strike-slip duplexes, laterally offset pre-existing features, and possible strained craters) from Galileo and Voyager images. We focus on complex structures associated with grooved terrain (e.g. Nun Sulcus, Dardanus Sulcus, Tiamat Sulcus, and Arbela Sulcus) and terrains transitional from dark to light terrain (e.g. the boundary between Nippur Sulcus and Marius Regio, including Byblus Sulcus and Philus Sulcus). Detailed structural interpretations suggest strong evidence of strike-slip faulting in some regions (i.e., Nun and Dardanus Sulcus); however, further investigation of additional strike-slip structures is required of less convincing regions (i.e., Byblus Sulcus). Where applicable, these results are synthesized into a global database representing an inferred sense of shear for many of Ganymede's fractures. Moreover, when combined with existing observations of extensional features, these results help to narrow down the range of possible principal stress directions that could have acted at the regional or global scale to produce grooved terrain on Ganymede.

Atomic force microscopy study of the structure function relationships of the biofilm-forming bacterium Streptococcus mutans

NASA Astrophysics Data System (ADS)

Cross, Sarah E.; Kreth, Jens; Zhu, Lin; Qi, Fengxia; Pelling, Andrew E.; Shi, Wenyuan; Gimzewski, James K.

2006-02-01

Atomic force microscopy (AFM) has garnered much interest in recent years for its ability to probe the structure, function and cellular nanomechanics inherent to specific biological cells. In particular, we have used AFM to probe the important structure-function relationships of the bacterium Streptococcus mutans. S. mutans is the primary aetiological agent in human dental caries (tooth decay), and is of medical importance due to the virulence properties of these cells in biofilm initiation and formation, leading to increased tolerance to antibiotics. We have used AFM to characterize the unique surface structures of distinct mutants of S. mutans. These mutations are located in specific genes that encode surface proteins, thus using AFM we have resolved characteristic surface features for mutant strains compared to the wild type. Ultimately, our characterization of surface morphology has shown distinct differences in the local properties displayed by various S. mutans strains on the nanoscale, which is imperative for understanding the collective properties of these cells in biofilm formation.

A Cryptic Species of the Tylonycteris pachypus Complex (Chiroptera: Vespertilionidae) and Its Population Genetic Structure in Southern China and nearby Regions

PubMed Central

HUANG, Chujing; YU, Wenhua; XU, Zhongxian; QIU, Yuanxiong; CHEN, Miao; QIU, Bing; MOTOKAWA, Masaharu; HARADA, Masashi; LI, Yuchun; WU, Yi

2014-01-01

Three distinct bamboo bat species (Tylonycteris) are known to inhabit tropical and subtropical areas of Asia, i.e., T. pachypus, T. robustula, and T. pygmaeus. This study performed karyotypic examinations of 4 specimens from southern Chinese T. p. fulvidus populations and one specimen from Thai T. p. fulvidus population, which detected distinct karyotypes (2n=30) compared with previous karyotypic descriptions of T. p. pachypus (2n=46) and T. robustula (2n=32) from Malaysia. This finding suggested a cryptic Tylonycteris species within T. pachypus complex in China and Thailand. Morphometric studies indicated the difficulty in distinguishing the cryptic species and T. p. pachypus from Indonesia apart from the external measurements, which might be the reason for their historical misidentification. Based on 623 bp mtDNA COI segments, a phylogeographic examination including T. pachypus individuals from China and nearby regions, i.e., Vietnam, Laos, and Cambodia, was conducted to examine the population genetic structure. Genealogical and phylogeographical results indicated that at least two diverged lineages existed in these regions (average 3.4 % of Kimura 2-parameter distances) and their population structure did not match the geographic pattern. These results suggested that at least two historical colonizations have occurred by the cryptic species. Furthermore, through integration of traditional and geometric morphological results, morphological differences on zygomatic arches, toothrows and bullae were detected between two lineages in China. Given the similarity of vegetation and climate of Guangdong and Guangxi regions, we suggested that such differences might be derived from their historical adaptation or distinct evolutionary history rather than the differences of habitats they occurred currently. PMID:24550688

Shallow Investigations of the Deep Seafloor: Quantitative Morphology in the Levant Basin, Eastern Mediterranean

NASA Astrophysics Data System (ADS)

Kanari, M.; Ketter, T.; Tibor, G.; Schattner, U.

2017-12-01

We aim to characterize the seafloor morphology and its shallow sub-surface structures and deformations in the deep part of the Levant basin (eastern Mediterranean) using recently acquired high-resolution shallow seismic reflection data and multibeam bathymetry, which allow quantitative analysis of morphology and structure. The Levant basin at the eastern Mediterranean is considered a passive continental margin, where most of the recent geological processes were related in literature to salt tectonics rooted at the Messinian deposits from 6Ma. We analyzed two sets of recently acquired high-resolution data from multibeam bathymetry and 3.5 kHz Chirp sub-bottom seismic reflection in the deep basin of the continental shelf offshore Israel (water depths up to 2100 m). Semi-automatic mapping of seafloor features and seismic data interpretation resulted in quantitative morphological analysis of the seafloor and its underlying sediment with penetration depth up to 60 m. The quantitative analysis and its interpretation are still in progress. Preliminary results reveal distinct morphologies of four major elements: channels, faults, folds and sediment waves, validated by seismic data. From the spatial distribution and orientation analyses of these phenomena, we identify two primary process types which dominate the formation of the seafloor in the Levant basin: structural and sedimentary. Characterization of the geological and geomorphological processes forming the seafloor helps to better understand the transport mechanisms and the relations between sediment transport and deposition in deep water and the shallower parts of the shelf and slope.

Comparative microbial diversity analyses of modern marine thrombolitic mats by barcoded pyrosequencing.

PubMed

Mobberley, Jennifer M; Ortega, Maya C; Foster, Jamie S

2012-01-01

Thrombolites are unlaminated carbonate structures that form as a result of the metabolic interactions of complex microbial mat communities. Thrombolites have a long geological history; however, little is known regarding the microbes associated with modern structures. In this study, we use a barcoded 16S rRNA gene-pyrosequencing approach coupled with morphological analysis to assess the bacterial, cyanobacterial and archaeal diversity associated with actively forming thrombolites found in Highborne Cay, Bahamas. Analyses revealed four distinct microbial mat communities referred to as black, beige, pink and button mats on the surfaces of the thrombolites. At a coarse phylogenetic resolution, the domain bacterial sequence libraries from the four mats were similar, with Proteobacteria and Cyanobacteria being the most abundant. At the finer resolution of the rRNA gene sequences, significant differences in community structure were observed, with dramatically different cyanobacterial communities. Of the four mat types, the button mats contained the highest diversity of Cyanobacteria, and were dominated by two sequence clusters with high similarity to the genus Dichothrix, an organism associated with the deposition of carbonate. Archaeal diversity was low, but varied in all mat types, and the archaeal community was predominately composed of members of the Thaumarchaeota and Euryarchaeota. The morphological and genetic data support the hypothesis that the four mat types are distinctive thrombolitic mat communities. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Modern freshwater microbialite analogues for ancient dendritic reef structures

NASA Technical Reports Server (NTRS)

Laval, B.; Cady, S. L.; Pollack, J. C.; McKay, C. P.; Bird, J. S.; Grotzinger, J. P.; Ford, D. C.; Bohm, H. R.

2000-01-01

Microbialites are organosedimentary structures that can be constructed by a variety of metabolically distinct taxa. Consequently, microbialite structures abound in the fossil record, although the exact nature of the biogeochemical processes that produced them is often unknown. One such class of ancient calcareous structures, Epiphyton and Girvanella, appear in great abundance during the Early Cambrian. Together with Archeocyathids, stromatolites and thrombolites, they formed major Cambrian reef belts. To a large extent, Middle to Late Cambrian reefs are similar to Precambrian reefs, with the exception that the latter, including terminal Proterozoic reefs, do not contain Epiphyton or Girvanella. Here we report the discovery in Pavilion Lake, British Columbia, Canada, of a distinctive assemblage of freshwater calcite microbialites, some of which display microstructures similar to the fabrics displayed by Epiphyton and Girvanella. The morphologies of the modern microbialites vary with depth, and dendritic microstructures of the deep water (> 30 m) mounds indicate that they may be modern analogues for the ancient calcareous structures. These microbialites thus provide an opportunity to study the biogeochemical interactions that produce fabrics similar to those of some enigmatic Early Cambrian reef structures.

Raman imaging of lignin and cellulose distribution in black spruce wood (Picea mariana) cell walls

Treesearch

Umesh P. Agarwal

2005-01-01

A detailed understanding of wood cell wall structure and organization is important from both fundamental and practical point of views. A state-of- the-art 633-nm laser based confocal Raman microscope was used in situ to investigate the cell wall organization of black spruce wood. Chemical information on lignin and cellulose from morphologically distinct cell wall...

White light emission of monolithic InGaN/GaN grown on morphology-controlled, nanostructured GaN templates.

PubMed

Song, Keun Man; Kim, Do-Hyun; Kim, Jong-Min; Cho, Chu-Young; Choi, Jehyuk; Kim, Kahee; Park, Jinsup; Kim, Hogyoug

2017-06-02

We demonstrated an InGaN/GaN-based, monolithic, white light-emitting diode (LED) without phosphors by using morphology-controlled active layers formed on multi-facet GaN templates containing polar and semipolar surfaces. The nanostructured surface morphology was controlled by changing the growth time, and distinct multiple photoluminescence peaks were observed at 360, 460, and 560 nm; these features were caused by InGaN/GaN-based multiple quantum wells (MQWs) on the nanostructured facets. The origin of each multi-peak was related to the different indium (In) compositions in the different planes of the quantum wells grown on the nanostructured GaN. The emitting units of MQWs in the LED structures were continuously connected, which is different from other GaN-based nanorod or nanowire LEDs. Therefore, the suggested structure had a larger active area. From the electroluminescence spectrum of the fabricated LED, monolithic white light emission with CIE color coordinates of x = 0.306 and y = 0.333 was achieved via multi-facet control combined with morphology control of the metal organic chemical vapor deposition-selective area growth of InGaN/GaN MQWs.

White light emission of monolithic InGaN/GaN grown on morphology-controlled, nanostructured GaN templates

NASA Astrophysics Data System (ADS)

Song, Keun Man; Kim, Do-Hyun; Kim, Jong-Min; Cho, Chu-Young; Choi, Jehyuk; Kim, Kahee; Park, Jinsup; Kim, Hogyoug

2017-06-01

We demonstrated an InGaN/GaN-based, monolithic, white light-emitting diode (LED) without phosphors by using morphology-controlled active layers formed on multi-facet GaN templates containing polar and semipolar surfaces. The nanostructured surface morphology was controlled by changing the growth time, and distinct multiple photoluminescence peaks were observed at 360, 460, and 560 nm; these features were caused by InGaN/GaN-based multiple quantum wells (MQWs) on the nanostructured facets. The origin of each multi-peak was related to the different indium (In) compositions in the different planes of the quantum wells grown on the nanostructured GaN. The emitting units of MQWs in the LED structures were continuously connected, which is different from other GaN-based nanorod or nanowire LEDs. Therefore, the suggested structure had a larger active area. From the electroluminescence spectrum of the fabricated LED, monolithic white light emission with CIE color coordinates of x = 0.306 and y = 0.333 was achieved via multi-facet control combined with morphology control of the metal organic chemical vapor deposition-selective area growth of InGaN/GaN MQWs.

Cirripede Cypris Antennules: How Much Structural Variation Exists Among Balanomorphan Species from Hard-Bottom Habitats?

PubMed

Chan, Benny K K; Sari, Alireza; Høeg, Jens T

2017-10-01

Barnacle cypris antennules are important for substratum attachment during settlement and on through metamorphosis from the larval stage to sessile adult. Studies on the morphology of cirripede cyprids are mostly qualitative, based on descriptions from images obtained using a scanning electron microscope (SEM). To our knowledge, our study is the first to use scanning electron microscopy to quantify overall structural diversity in cypris antennules by measuring 26 morphological parameters, including the structure of sensory organs. We analyzed cyprids from seven species of balanomorphan barnacles inhabiting rocky shore communities; for comparison, we also included a sponge-inhabiting balanomorphan and a verrucomorphan species. Multivariate analysis of the structural parameters resulted in two distinct clusters of species. From nonmetric multidimensional scaling plots, the sponge-inhabiting Balanus spongicola and Verruca stroemia formed one cluster, while the other balanomorphan species, all from hard bottoms, grouped together in the other cluster. The shape of the attachment disk on segment 3 is the key parameter responsible for the separation into two clusters. The present results show that species from a coastal hard-bottom habitat may share a nearly identical antennular structure that is distinct from barnacles from other habitats, and this finding supports the fact that such species also have rather similar reactions to substratum cues during settlement. Any differences that may be found in settlement biology among such species must therefore be due either to differences in the properties of their adhesive mechanisms or to the way that sensory stimuli are detected by virtually identical setae and processed into settlement behavior by the cyprid.

The taccalonolides and paclitaxel cause distinct effects on microtubule dynamics and aster formation

PubMed Central

2014-01-01

Background Microtubule stabilizers suppress microtubule dynamics and, at the lowest antiproliferative concentrations, disrupt the function of mitotic spindles, leading to mitotic arrest and apoptosis. At slightly higher concentrations, these agents cause the formation of multiple mitotic asters with distinct morphologies elicited by different microtubule stabilizers. Results We tested the hypothesis that two classes of microtubule stabilizing drugs, the taxanes and the taccalonolides, cause the formation of distinct aster structures due, in part, to differential effects on microtubule dynamics. Paclitaxel and the taccalonolides suppressed the dynamics of microtubules formed from purified tubulin as well as in live cells. Both agents suppressed microtubule dynamic instability, with the taccalonolides having a more pronounced inhibition of microtubule catastrophe, suggesting that they stabilize the plus ends of microtubules more effectively than paclitaxel. Live cell microscopy was also used to evaluate the formation and resolution of asters after drug treatment. While each drug had similar effects on initial formation, substantial differences were observed in aster resolution. Paclitaxel-induced asters often coalesced over time resulting in fewer, larger asters whereas numerous compact asters persisted once they were formed in the presence of the taccalonolides. Conclusions We conclude that the increased resistance of microtubule plus ends to catastrophe may play a role in the observed inability of taccalonolide-induced asters to coalesce during mitosis, giving rise to the distinct morphologies observed after exposure to these agents. PMID:24576146

Distinct Particle Morphologies Revealed through Comparative Parallel Analyses of Retrovirus-Like Particles.

PubMed

Martin, Jessica L; Cao, Sheng; Maldonado, Jose O; Zhang, Wei; Mansky, Louis M

2016-09-15

The Gag protein is the main retroviral structural protein, and its expression alone is usually sufficient for production of virus-like particles (VLPs). In this study, we sought to investigate-in parallel comparative analyses-Gag cellular distribution, VLP size, and basic morphological features using Gag expression constructs (Gag or Gag-YFP, where YFP is yellow fluorescent protein) created from all representative retroviral genera: Alpharetrovirus, Betaretrovirus, Deltaretrovirus, Epsilonretrovirus, Gammaretrovirus, Lentivirus, and Spumavirus. We analyzed Gag cellular distribution by confocal microscopy, VLP budding by thin-section transmission electron microscopy (TEM), and general morphological features of the VLPs by cryogenic transmission electron microscopy (cryo-TEM). Punctate Gag was observed near the plasma membrane for all Gag constructs tested except for the representative Beta- and Epsilonretrovirus Gag proteins. This is the first report of Epsilonretrovirus Gag localizing to the nucleus of HeLa cells. While VLPs were not produced by the representative Beta- and Epsilonretrovirus Gag proteins, the other Gag proteins produced VLPs as confirmed by TEM, and morphological differences were observed by cryo-TEM. In particular, we observed Deltaretrovirus-like particles with flat regions of electron density that did not follow viral membrane curvature, Lentivirus-like particles with a narrow range and consistent electron density, suggesting a tightly packed Gag lattice, and Spumavirus-like particles with large envelope protein spikes and no visible electron density associated with a Gag lattice. Taken together, these parallel comparative analyses demonstrate for the first time the distinct morphological features that exist among retrovirus-like particles. Investigation of these differences will provide greater insights into the retroviral assembly pathway. Comparative analysis among retroviruses has been critically important in enhancing our understanding of retroviral replication and pathogenesis, including that of important human pathogens such as human T-cell leukemia virus type 1 (HTLV-1) and HIV-1. In this study, parallel comparative analyses have been used to study Gag expression and virus-like particle morphology among representative retroviruses in the known retroviral genera. Distinct differences were observed, which enhances current knowledge of the retroviral assembly pathway. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Morphology, bioacoustics, and ecology of Tibicen neomexicensis sp. n., a new species of cicada from the Sacramento Mountains in New Mexico, U.S.A. (Hemiptera, Cicadidae, Tibicen)

PubMed Central

Stucky, Brian J.

2013-01-01

Abstract Tibicen neomexicensis sp. n., a new species of cicada found in the Sacramento Mountains of southcentral New Mexico, is described. Tibicen neomexicensis closely resembles Tibicen chiricahua Davis morphologically, but males of the two species have highly distinct calling songs that differ in phrasal structure, amplitude burst rates, and pulse structure. Unlike Tibicen chiricahua, male Tibicen neomexicensis use conspicuous dorso-ventral abdominal movements to modulate the amplitude and frequency of their calls. Tibicen neomexicensis is also smaller on average than Tibicen chiricahua, and differences in the color patterns of the wing venation identify these two species morphologically. Both species are dependent on pinyon-juniper woodlands and have similar emergence phenologies. These species appear to be allopatric, with Tibicen chiricahua found west of the Rio Grande in New Mexico, Arizona, and Mexico, and Tibicen neomexicensis so far known only from New Mexico, east of the Rio Grande. Tibicen chiricahua and Tibicen neomexicensis males share a common genitalic structure that separates them from all other species of Tibicen, and the possible evolutionary and biogeographic history of these likely sister species is also discussed. PMID:24146578

Morphology, bioacoustics, and ecology of Tibicen neomexicensis sp. n., a new species of cicada from the Sacramento Mountains in New Mexico, U.S.A. (Hemiptera, Cicadidae, Tibicen).

PubMed

Stucky, Brian J

2013-01-01

Tibicen neomexicensis sp. n., a new species of cicada found in the Sacramento Mountains of southcentral New Mexico, is described. Tibicen neomexicensis closely resembles Tibicen chiricahua Davis morphologically, but males of the two species have highly distinct calling songs that differ in phrasal structure, amplitude burst rates, and pulse structure. Unlike Tibicen chiricahua, male Tibicen neomexicensis use conspicuous dorso-ventral abdominal movements to modulate the amplitude and frequency of their calls. Tibicen neomexicensis is also smaller on average than Tibicen chiricahua, and differences in the color patterns of the wing venation identify these two species morphologically. Both species are dependent on pinyon-juniper woodlands and have similar emergence phenologies. These species appear to be allopatric, with Tibicen chiricahua found west of the Rio Grande in New Mexico, Arizona, and Mexico, and Tibicen neomexicensis so far known only from New Mexico, east of the Rio Grande. Tibicen chiricahua and Tibicen neomexicensis males share a common genitalic structure that separates them from all other species of Tibicen, and the possible evolutionary and biogeographic history of these likely sister species is also discussed.

Morphologic Subtypes of Hepatocellular Carcinoma.

PubMed

Torbenson, Michael S

2017-06-01

Hepatocellular carcinomas can be further divided into distinct subtypes that provide important clinical information and biological insights. These subtypes are distinct from growth patterns and are on based on morphologic and molecular findings. There are 12 reasonably well-defined subtypes as well as 6 provisional subtypes, together making up 35% of all hepatocellular carcinomas. These subtypes are discussed, with an emphasis on their definitions and the key morphologic findings. Copyright © 2017 Elsevier Inc. All rights reserved.

Functional Zoning and Urban Development Tendencies of Bucharest City/Romania

NASA Astrophysics Data System (ADS)

Armas, Iuliana; Dumitrascu, Silvia

2010-05-01

Any form of urban development policy for environmental management should be based on the differentiation of the structure of a territory that can be found in the shape of functional zoning. Identifying the patterns of morphological structure of the urban space can provide essential clues concerning the proper measures to take into consideration during the activity of urban planning. In this sense, the Bucharest municipality study case provides the example of a dynamic urban space with a complex and distinctive evolutionary structure. The aim of the study is to set out the main events that shaped the Bucharest city space and the patterns resulted from their impact at the functional level of the Romanian capital. In order to identify the development tendencies of the Bucharest municipality, a series of aspects concerning urban morphology should be highlighted that reveal the impact of the socio-economical policies at the structural level of the territory. In this sense, three images of the urban space stand out, representative for the period when they materialized: the Post-Byzantine (XV-XVIII), the Fanariot (XVIII) and the Modern periods (XIX-XX). The corresponding cartographic documents analyzed are: the Franz Purcel Plan (dated 1789), the Romanian Guide Print Plan and, respectively, the AGC Busman Print Plan. The analysis reveals three distinctive morphological types: radial-concentric in the 17th century, polynuclear in the 18th century, leading to the mixed character in the Modern period. The latest trait of the urban territory is based on the concentric character of the street network (three circles were identified at the level of the capital city that point out the evolution of the urban space: Dacia bv-Mircea Vulcanescu, Stefan cel Mare bv-Iancu de Hunedoara and the last circle outlined by the ring road) and the presence of multiple nuclei that accumulate the commercial, administrative and business functions of the city.

Canine perineal tumours.

PubMed

Berrocal, A; Vos, J H; van den Ingh, T S; Molenbeek, R F; van Sluijs, F J

1989-12-01

One hundred and thirty nine canine perineal tumours were histologically evaluated. The vast majority (134 tumours = 96.4%) appeared to originate from the characteristic glandular structures of this region. They were classified as well differentiated perianal gland tumours (58.3%), as moderately or poorly differentiated perianal gland tumours (21.6%) and as carcinomas without perianal gland differentiation (16.5%). Only 5 tumours (3.6%) appeared to originate from non-characteristic perineal structures. A prominent male predominance was found with respect to the perianal gland tumours, whereas the carcinomas showed a distinct female predisposition. Tumours showing perianal gland differentiation almost invariably will have a benign behaviour. The carcinomas lacking any perianal gland differentiation often show a distinct malignant behaviour with metastases to regional lymph nodes and internal organs. These malignant neoplasms showed morphological and clinical features comparable to canine anal sac gland adenocarcinomas and carcinoids in man and animals.

Generation of a Multicomponent Library of Disulfide Donor-Acceptor Architectures Using Dynamic Combinatorial Chemistry

PubMed Central

Drożdż, Wojciech; Kołodziejski, Michał; Markiewicz, Grzegorz; Jenczak, Anna; Stefankiewicz, Artur R.

2015-01-01

We describe here the generation of new donor-acceptor disulfide architectures obtained in aqueous solution at physiological pH. The application of a dynamic combinatorial chemistry approach allowed us to generate a large number of new disulfide macrocyclic architectures together with a new type of [2]catenanes consisting of four distinct components. Up to fifteen types of structurally-distinct dynamic architectures have been generated through one-pot disulfide exchange reactions between four thiol-functionalized aqueous components. The distribution of disulfide products formed was found to be strongly dependent on the structural features of the thiol components employed. This work not only constitutes a success in the synthesis of topologically- and morphologically-complex targets, but it may also open new horizons for the use of this methodology in the construction of molecular machines. PMID:26193265

Generation of a Multicomponent Library of Disulfide Donor-Acceptor Architectures Using Dynamic Combinatorial Chemistry.

PubMed

Drożdż, Wojciech; Kołodziejski, Michał; Markiewicz, Grzegorz; Jenczak, Anna; Stefankiewicz, Artur R

2015-07-17

We describe here the generation of new donor-acceptor disulfide architectures obtained in aqueous solution at physiological pH. The application of a dynamic combinatorial chemistry approach allowed us to generate a large number of new disulfide macrocyclic architectures together with a new type of [2]catenanes consisting of four distinct components. Up to fifteen types of structurally-distinct dynamic architectures have been generated through one-pot disulfide exchange reactions between four thiol-functionalized aqueous components. The distribution of disulfide products formed was found to be strongly dependent on the structural features of the thiol components employed. This work not only constitutes a success in the synthesis of topologically- and morphologically-complex targets, but it may also open new horizons for the use of this methodology in the construction of molecular machines.

On the Distinction between Regular and Irregular Inflectional Morphology: Evidence from Dinka

ERIC Educational Resources Information Center

Ladd, D. Robert; Remijsen, Bert; Manyang, Caguor Adong

2009-01-01

Discussions of the psycholinguistic significance of regularity in inflectional morphology generally deal with languages in which regular forms can be clearly identified and revolve around whether there are distinct processing mechanisms for regular and irregular forms. We present a detailed description of Dinka's notoriously irregular noun number…

Using Intact Iron Microbial Mats to Gain Insights Into Mat Ecology and Geochemical Niche at the Microbial Scale

NASA Astrophysics Data System (ADS)

Glazer, B. T.; Chan, C. S. Y.; Mcallister, S.; Leavitt, A.; Emerson, D.

2015-12-01

Microbial mats are formed by microorganisms working in coordinated symbiosis, often benefitting the community by controlling the local geochemical or physical environment. Thus, the ecology of the mat depends on the individual roles of microbes organized into niches within a larger architecture. Chemolithotrophic Fe-oxidizing bacteria (FeOB) form distinctive Fe oxyhydroxide biominerals which constitute the building blocks of the mat. However, the majority of our progress has been in understanding the overall community structure. Understanding the physical mat structure on the microbial scale is important to unraveling FeOB evolution, the biogeochemistry and ecology of Fe-rich habitats, and ultimately interpreting FeOB biosignatures in the rock record. Mats in freshwater and marine environments contain strikingly similar biomineral morphologies, yet they are formed by phylogenetically distinct microorganisms. This suggests that the overall architecture and underlying genetics of freshwater and marine mats has evolved to serve particular roles specific to Fe oxidation. Thus, we conducted a comparative study of Fe seep freshwater mats and marine hydrothermal mats. We have developed a new approach to sampling Fe mats in order to preserve the delicate structure for analysis by confocal and scanning electron microscopy. Our analyses of these intact mats show that freshwater and marine mats are similarly initiated by a single type of structure-former. These ecosystem engineers form either a hollow sheath or a twisted stalk biomineral during mat formation, with a highly directional structure. These microbes appear to be the vanguard organisms that anchor the community within oxygen/Fe(II) gradients, further allowing for community succession in the mat interior as evidenced by other mineralized morphologies. Patterns in biomineral thickness and directionality were indicative of redox gradients and temporal changes in the geochemical environment. These observations show that the FeOB create the structure of the environment for the entire microbial community, acting as environmental engineers. Furthermore, they leave behind distinctive signatures of environmental conditions (e.g. presence of oxygen, hydrothermal pulsing), which can be recorded in the rock record.

Pump-probe imaging of pigmented cutaneous melanoma primary lesions gives insight into metastatic potential

PubMed Central

Robles, Francisco E.; Deb, Sanghamitra; Wilson, Jesse W.; Gainey, Christina S.; Selim, M. Angelica; Mosca, Paul J.; Tyler, Douglas S.; Fischer, Martin C.; Warren, Warren S.

2015-01-01

Metastatic melanoma is associated with a poor prognosis, but no method reliably predicts which melanomas of a given stage will ultimately metastasize and which will not. While sentinel lymph node biopsy (SLNB) has emerged as the most powerful predictor of metastatic disease, the majority of people dying from metastatic melanoma still have a negative SLNB. Here we analyze pump-probe microscopy images of thin biopsy slides of primary melanomas to assess their metastatic potential. Pump-probe microscopy reveals detailed chemical information of melanin with subcellular spatial resolution. Quantification of the molecular signatures without reference standards is achieved using a geometrical representation of principal component analysis. Melanin structure is analyzed in unison with the chemical information by applying principles of mathematical morphology. Results show that melanin in metastatic primary lesions has lower chemical diversity than non-metastatic primary lesions, and contains two distinct phenotypes that are indicative of aggressive disease. Further, the mathematical morphology analysis reveals melanin in metastatic primary lesions has a distinct “dusty” quality. Finally, a statistical analysis shows that the combination of the chemical information with spatial structures predicts metastatic potential with much better sensitivity than SLNB and high specificity, suggesting pump-probe microscopy can be an important tool to help predict the metastatic potential of melanomas. PMID:26417529

Comparative histological study of the mammalian facial nucleus.

PubMed

Furutani, Rui; Sugita, Shoei

2008-04-01

We performed comparative Nissl, Klüver-Barrera and Golgi staining studies of the mammalian facial nucleus to classify the morphologically distinct subdivisions and the neuronal types in the rat, rabbit, ferret, Japanese monkey (Macaca fuscata), pig, horse, Risso's dolphin (Grampus griseus), and bottlenose dolphin (Tursiops truncatus). The medial subnucleus was observed in all examined species; however, that of the Risso's and bottlenose dolphins was a poorly-developed structure comprised of scattered neurons. The medial subnuclei of terrestrial mammals were well-developed cytoarchitectonic structures, usually a rounded column comprised of densely clustered neurons. Intermediate and lateral subnuclei were found in all studied mammals, with differences in columnar shape and neuronal types from species to species. The dorsolateral subnucleus was detected in all mammals but the Japanese monkey, whose facial neurons converged into the intermediate subnucleus. The dorsolateral subnuclei of the two dolphin species studied were expanded subdivisions comprised of densely clustered cells. The ventromedial subnuclei of the ferret, pig, and horse were richly-developed columns comprised of large multipolar neurons. Pig and horse facial nuclei contained another ventral cluster, the ventrolateral subnucleus. The facial nuclei of the Japanese monkey and the bottlenose dolphin were similar in their ventral subnuclear organization. Our findings show species-specific subnuclear organization and distribution patterns of distinct types of neurons within morphological discrete subdivisions, reflecting functional differences.

Normal age-related brain morphometric changes: nonuniformity across cortical thickness, surface area and gray matter volume?

PubMed

Lemaitre, Herve; Goldman, Aaron L; Sambataro, Fabio; Verchinski, Beth A; Meyer-Lindenberg, Andreas; Weinberger, Daniel R; Mattay, Venkata S

2012-03-01

Normal aging is accompanied by global as well as regional structural changes. While these age-related changes in gray matter volume have been extensively studied, less has been done using newer morphological indexes, such as cortical thickness and surface area. To this end, we analyzed structural images of 216 healthy volunteers, ranging from 18 to 87 years of age, using a surface-based automated parcellation approach. Linear regressions of age revealed a concomitant global age-related reduction in cortical thickness, surface area and volume. Cortical thickness and volume collectively confirmed the vulnerability of the prefrontal cortex, whereas in other cortical regions, such as in the parietal cortex, thickness was the only measure sensitive to the pronounced age-related atrophy. No cortical regions showed more surface area reduction than the global average. The distinction between these morphological measures may provide valuable information to dissect age-related structural changes of the brain, with each of these indexes probably reflecting specific histological changes occurring during aging. Published by Elsevier Inc.

Self-(Un)rolling Biopolymer Microstructures: Rings, Tubules, and Helical Tubules from the Same Material.

PubMed

Ye, Chunhong; Nikolov, Svetoslav V; Calabrese, Rossella; Dindar, Amir; Alexeev, Alexander; Kippelen, Bernard; Kaplan, David L; Tsukruk, Vladimir V

2015-07-13

We have demonstrated the facile formation of reversible and fast self-rolling biopolymer microstructures from sandwiched active-passive, silk-on-silk materials. Both experimental and modeling results confirmed that the shape of individual sheets effectively controls biaxial stresses within these sheets, which can self-roll into distinct 3D structures including microscopic rings, tubules, and helical tubules. This is a unique example of tailoring self-rolled 3D geometries through shape design without changing the inner morphology of active bimorph biomaterials. In contrast to traditional organic-soluble synthetic materials, we utilized a biocompatible and biodegradable biopolymer that underwent a facile aqueous layer-by-layer (LbL) assembly process for the fabrication of 2D films. The resulting films can undergo reversible pH-triggered rolling/unrolling, with a variety of 3D structures forming from biopolymer structures that have identical morphology and composition. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Continuous structural evolution of calcium carbonate particles: a unifying model of copolymer-mediated crystallization.

PubMed

Kulak, Alex N; Iddon, Peter; Li, Yuting; Armes, Steven P; Cölfen, Helmut; Paris, Oskar; Wilson, Rory M; Meldrum, Fiona C

2007-03-28

Two double-hydrophilic block copolymers, each comprising a nonionic block and an anionic block comprising pendent aromatic sulfonate groups, were used as additives to modify the crystallization of CaCO3. Marked morphological changes in the CaCO3 particles were observed depending on the reaction conditions used. A poly(ethylene oxide)-b-poly(sodium 4-styrenesulfonate) diblock copolymer was particularly versatile in effecting a morphological change in calcite particles, and a continuous structural transition in the product particles from polycrystalline to mesocrystal to single crystal was observed with variation in the calcium concentration. The existence of this structural sequence provides unique insight into the mechanism of polymer-mediated crystallization. We propose that it reflects continuity in the crystallization mechanism itself, spanning the limits from nonoriented aggregation of nanoparticles to classical ion-by-ion growth. The various pathways to polycrystalline, mesocrystal, and single-crystal particles, which had previously been considered to be distinct, therefore all form part of a unifying crystallization framework based on the aggregation of precursor subunits.

Dynamics of nanoparticle morphology under low energy ion irradiation.

PubMed

Holland-Moritz, Henry; Graupner, Julia; Möller, Wolfhard; Pacholski, Claudia; Ronning, Carsten

2018-08-03

If nanostructures are irradiated with energetic ions, the mechanism of sputtering becomes important when the ion range matches about the size of the nanoparticle. Gold nanoparticles with diameters of ∼50 nm on top of silicon substrates with a native oxide layer were irradiated by gallium ions with energies ranging from 1 to 30 keV in a focused ion beam system. High resolution in situ scanning electron microscopy imaging permits detailed insights in the dynamics of the morphology change and sputter yield. Compared to bulk-like structures or thin films, a pronounced shaping and enhanced sputtering in the nanostructures occurs, which enables a specific shaping of these structures using ion beams. This effect depends on the ratio of nanoparticle size and ion energy. In the investigated energy regime, the sputter yield increases at increasing ion energy and shows a distinct dependence on the nanoparticle size. The experimental findings are directly compared to Monte Carlo simulations obtained from iradina and TRI3DYN, where the latter takes into account dynamic morphological and compositional changes of the target.

Morphological imaging and quantification of axial xylem tissue in Fraxinus excelsior L. through X-ray micro-computed tomography.

PubMed

Koddenberg, Tim; Militz, Holger

2018-05-05

The popularity of X-ray based imaging methods has continued to increase in research domains. In wood research, X-ray micro-computed tomography (XμCT) is useful for structural studies examining the three-dimensional and complex xylem tissue of trees qualitatively and quantitatively. In this study, XμCT made it possible to visualize and quantify the spatial xylem organization of the angiosperm species Fraxinus excelsior L. on the microscopic level. Through image analysis, it was possible to determine morphological characteristics of the cellular axial tissue (vessel elements, fibers, and axial parenchyma cells) three-dimensionally. X-ray imaging at high resolutions provides very distinct visual insight into the xylem structure. Numerical analyses performed through semi-automatic procedures made it possible to quickly quantify cell characteristics (length, diameter, and volume of cells). Use of various spatial resolutions (0.87-5 μm) revealed boundaries users should be aware of. Nevertheless, our findings, both qualitative and quantitative, demonstrate XμCT to be a valuable tool for studying the spatial cell morphology of F. excelsior. Copyright © 2018. Published by Elsevier Ltd.

Dimorphic ejaculates and sperm release strategies associated with alternative mating behaviors in the squid.

PubMed

Apostólico, Lígia H; Marian, José E A R

2017-11-01

Sperm competition is a powerful postcopulatory selective force influencing male adaptations associated with increasing fertilization success, and it is usually related to the evolution of different strategies of ejaculate expenditure between individuals. Ejaculates may also be influenced by additional selective pressures associated with sperm competition, such as timing between insemination and fertilization, female reproductive tract morphology, and fertilization environment. Also, males that adopt alternative mating tactics may face distinct sperm competition pressures, which may lead to the evolution of intraspecific diversity in ejaculates. In loliginid squids, males with alternative reproductive tactics (sneakers and consorts) differ not only in mating behavior, but also transfer spermatophores into two distinct sites within the female. Here, we compared structure and functioning of spermatophores between sneakers and consorts in the squid Doryteuthis plei applying microscopy techniques and in vitro experiments. Sneakers and consorts exhibit differences in spermatophore structure that lead to distinct spermatophoric reactions and spermatangium morphologies. Moreover, in sneakers, sperm release lasts longer and their sperm show an aggregative behavior not detected in consorts. Slow sperm release may be a strategy to guarantee longer sperm provision, given the wide interval between sneaker mating and egg release. For consorts, in turn, intense and quick sperm discharge may be advantageous, as timing between mating and egg-laying is relatively short. Within the complex squid mating system, factors such as (i) different fertilization sites and (ii) interval between mating and egg release may also influence sperm competition, and ultimately shape the evolution of divergent ejaculates between dimorphic males. © 2017 Wiley Periodicals, Inc.

Biomimetics of fetal alveolar flow phenomena using microfluidics.

PubMed

Tenenbaum-Katan, Janna; Fishler, Rami; Rothen-Rutishauser, Barbara; Sznitman, Josué

2015-01-01

At the onset of life in utero, the respiratory system begins as a liquid-filled tubular organ and undergoes significant morphological changes during fetal development towards establishing a respiratory organ optimized for gas exchange. As airspace morphology evolves, respiratory alveolar flows have been hypothesized to exhibit evolving flow patterns. In the present study, we have investigated flow topologies during increasing phases of embryonic life within an anatomically inspired microfluidic device, reproducing real-scale features of fetal airways representative of three distinct phases of in utero gestation. Micro-particle image velocimetry measurements, supported by computational fluid dynamics simulations, reveal distinct respiratory alveolar flow patterns throughout different stages of fetal life. While attached, streamlined flows characterize the shallow structures of premature alveoli indicative of the onset of saccular stage, separated recirculating vortex flows become the signature of developed and extruded alveoli characteristic of the advanced stages of fetal development. To further mimic physiological aspects of the cellular environment of developing airways, our biomimetic devices integrate an alveolar epithelium using the A549 cell line, recreating a confluent monolayer that produces pulmonary surfactant. Overall, our in vitro biomimetic fetal airways model delivers a robust and reliable platform combining key features of alveolar morphology, flow patterns, and physiological aspects of fetal lungs developing in utero.

Parallel Patterns of Host-Specific Morphology and Genetic Admixture in Sister Lineages of a Commensal Barnacle.

PubMed

Ewers-Saucedo, Christine; Chan, Benny K K; Zardus, John D; Wares, John P

2017-06-01

Symbiotic relationships are often species specific, allowing symbionts to adapt to their host environments. Host generalists, on the other hand, have to cope with diverse environments. One coping strategy is phenotypic plasticity, defined by the presence of host-specific phenotypes in the absence of genetic differentiation. Recent work indicates that such host-specific phenotypic plasticity is present in the West Pacific lineage of the commensal barnacle Chelonibia testudinaria (Linnaeus, 1758). We investigated genetic and morphological host-specific structure in the genetically distinct Atlantic sister lineage of C. testudinaria. We collected adult C. testudinaria from loggerhead sea turtles, horseshoe crabs, and blue crabs along the eastern U.S. coast between Delaware and Florida and in the Gulf of Mexico off Mississippi. We find that shell morphology, especially shell thickness, is host specific and comparable in similar host species between the Atlantic and West Pacific lineages. We did not detect significant genetic differentiation related to host species when analyzing data from 11 nuclear microsatellite loci and mitochondrial sequence data, which is comparable to findings for the Pacific lineage. The most parsimonious explanation for these parallel patterns between distinct lineages of C. testudinaria is that C. testudinaria maintained phenotypic plasticity since the lineages diverged 4-5 mya.

Tunable Affinity and Molecular Architecture Lead to Diverse Self-Assembled Supramolecular Structures in Thin Films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, Chih-Hao; Dong, Xue-Hui; Lin, Zhiwei

2015-12-03

The self-assembly behaviors of specifically designed giant surfactants are systematically studied in thin films using grazing incident X-ray and transmission electron microscopy (TEM), focusing on the effects of head surface functionalities and molecular architectures on nanostructure formation. Two molecular nanoparticles (MNPs) with different affinities, i.e., hydrophilic carboxylic acid functionalized [60]fullerene (AC60) and omniphobic fluorinated polyhedral oligomeric silsesquioxane (FPOSS), are utilized as heads of the giant surfactants. By covalently tethering these functional MNPs onto the chain end or the junction point of polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer, linear and star-like giant surfactants possess distinct molecular architectures are constructed. With fixed lengthmore » of the PEO block, the molecular weight change of the PS block originates the phase formation and transition. Due to the distinct affinity, the AC60-based giant surfactants form two-component morphologies, while three-component morphologies are found in the FPOSS-based ones. A PS block stretching parameter is introduced to characterize the PS chain conformation in different morphologies. The highly diverse self-assembly behaviors and the tunable dimensions in thin films suggest the giant surfactants could be a promising and robust platform for nanolithography applications.« less

Morphological Evolution of Block Copolymer Particles: Effect of Solvent Evaporation Rate on Particle Shape and Morphology.

PubMed

Shin, Jae Man; Kim, YongJoo; Yun, Hongseok; Yi, Gi-Ra; Kim, Bumjoon J

2017-02-28

Shape and morphology of polymeric particles are of great importance in controlling their optical properties or self-assembly into unusual superstructures. Confinement of block copolymers (BCPs) in evaporative emulsions affords particles with diverse structures, including prolate ellipsoids, onion-like spheres, oblate ellipsoids, and others. Herein, we report that the evaporation rate of solvent from emulsions encapsulating symmetric polystyrene-b-polybutadiene (PS-b-PB) determines the shape and internal nanostructure of micron-sized BCP particles. A distinct morphological transition from the ellipsoids with striped lamellae to the onion-like spheres was observed with decreasing evaporation rate. Experiments and dissipative particle dynamics (DPD) simulations showed that the evaporation rate affected the organization of BCPs at the particle surface, which determined the final shape and internal nanostructure of the particles. Differences in the solvent diffusion rates in PS and PB at rapid evaporation rates induced alignment of both domains perpendicular to the particle surface, resulting in ellipsoids with axial lamellar stripes. Slower evaporation rates provided sufficient time for BCP organization into onion-like structures with PB as the outermost layer, owing to the preferential interaction of PB with the surroundings. BCP molecular weight was found to influence the critical evaporation rate corresponding to the morphological transition from ellipsoid to onion-like particles, as well as the ellipsoid aspect ratio. DPD simulations produced morphologies similar to those obtained from experiments and thus elucidated the mechanism and driving forces responsible for the evaporation-induced assembly of BCPs into particles with well-defined shapes and morphologies.

When linearity prevails over hierarchy in syntax

PubMed Central

Willer Gold, Jana; Arsenijević, Boban; Batinić, Mia; Becker, Michael; Čordalija, Nermina; Kresić, Marijana; Leko, Nedžad; Marušič, Franc Lanko; Milićev, Tanja; Milićević, Nataša; Mitić, Ivana; Peti-Stantić, Anita; Stanković, Branimir; Šuligoj, Tina; Tušek, Jelena; Nevins, Andrew

2018-01-01

Hierarchical structure has been cherished as a grammatical universal. We use experimental methods to show where linear order is also a relevant syntactic relation. An identical methodology and design were used across six research sites on South Slavic languages. Experimental results show that in certain configurations, grammatical production can in fact favor linear order over hierarchical structure. However, these findings are limited to coordinate structures and distinct from the kind of production errors found with comparable configurations such as “attraction” errors. The results demonstrate that agreement morphology may be computed in a series of steps, one of which is partly independent from syntactic hierarchy. PMID:29288218

Molecular phylogeny and larval morphological diversity of the lanternfish genus Hygophum (Teleostei: Myctophidae).

PubMed

Yamaguchi, M; Miya, M; Okiyama, M; Nishida, M

2000-04-01

Larvae of the deep-sea lanternfish genus Hygophum (Myctophidae) exhibit a remarkable morphological diversity that is quite unexpected, considering their homogeneous adult morphology. In an attempt to elucidate the evolutionary patterns of such larval morphological diversity, nucleotide sequences of a portion of the mitochondrially encoded 16S ribosomal RNA gene were determined for seven Hygophum species and three outgroup taxa. Secondary structure-based alignment resulted in a character matrix consisting of 1172 bp of unambiguously aligned sequences, which were subjected to phylogenetic analyses using maximum-parsimony, maximum-likelihood, and neighbor-joining methods. The resultant tree topologies from the three methods were congruent, with most nodes, including that of the genus Hygophum, being strongly supported by various tree statistics. The most parsimonious reconstruction of the three previously recognized, distinct larval morphs onto the molecular phylogeny revealed that one of the morphs had originated as the common ancestor of the genus, the other two having diversified separately in two subsequent major clades. The patterns of such diversification are discussed in terms of the unusual larval eye morphology and geographic distribution. Copyright 2000 Academic Press.

Stabilizing Various Bicontinuous Morphologies via Polydispersity of Diblock Copolymers

NASA Astrophysics Data System (ADS)

Lai, Chi To; Shi, An-Chang

Diblock copolymers are macromolecules composed of two chemically distinct homopolymers covalently bound end-to-end. The ability to self-assembly into a wide variety of ordered periodic structures, as means of minimizing the free energy, is their most well-studied property. There are many factors affecting the observed equilibrium morphology, one of which is polydispersity. The phase behaviour of polydispersed diblock copolymers is more rich, and diverse when compared to their monodispersed counterpart. The rich behaviour of polydispersed diblock copolymers provides an opportunity to engineer novel morphologies which are not available in monodispersed systems. Using the self-consistent field theory (SCFT), we explore the possibility of exploiting polydispersity of diblock copolymers in binary mixtures to stabilize the various bicontinuous phases, such as the double-diamond morphology. Specifically, solutions of the SCFT equations corresponding to different bicontinuous phases are obtained numerically for binary mixtures of diblock copolymers. The relative stability of the different ordered phases is examined by comparing their free energy. From the study, we determine optimal sets of parameters that stabilize the double-diamond or other exotic morphologies.

Topographic Cues Reveal Two Distinct Spreading Mechanisms in Blood Platelets

PubMed Central

Sandmann, Rabea; Köster, Sarah

2016-01-01

Blood platelets are instrumental in blood clotting and are thus heavily involved in early wound closure. After adhering to a substrate they spread by forming protrusions like lamellipodia and filopodia. However, the interaction of these protrusions with the physical environment of platelets while spreading is not fully understood. Here we dynamically image platelets during this spreading process and compare their behavior on smooth and on structured substrates. In particular we analyze the temporal evolution of the spread area, the cell morphology and the dynamics of individual filopodia. Interestingly, the topographic cues enable us to distinguish two spreading mechanisms, one that is based on numerous persistent filopodia and one that rather involves lamellipodia. Filopodia-driven spreading coincides with a strong response of platelet morphology to the substrate topography during spreading, whereas lamellipodia-driven spreading does not. Thus, we quantify different degrees of filopodia formation in platelets and the influence of filopodia in spreading on structured substrates. PMID:26934830

Sidescan backscatter variations of cold seeps on the Hikurangi Margin (New Zealand): indications for different stages in seep development

NASA Astrophysics Data System (ADS)

Dumke, Ines; Klaucke, Ingo; Berndt, Christian; Bialas, Jörg

2014-06-01

Cold seeps on the Hikurangi Margin off New Zealand exhibit various seabed morphologies producing different intensity patterns in sidescan backscatter images. Acoustic backscatter characteristics of 25 investigated seep sites fall into four distinct types characterised by variations in backscatter intensity, distribution and inferred structural heights. The types reflect different carbonate morphologies including up to 20-m-high structures (type 1), low-relief crusts (type 2), scattered blocks (type 3) and carbonate-free sites (type 4). Each seep corresponds to a single type; intermediates were not observed. This correlates well with published data on seep fauna at each site, with the four types representing three different faunal habitats of successive stages of seep development. Backscatter signatures in sidescan sonar images of cold seeps may therefore serve as a convenient proxy for variations in faunal habitats.

Interparticle interactions effects on the magnetic order in surface of FeO4 nanoparticles.

PubMed

Lima, E; Vargas, J M; Rechenberg, H R; Zysler, R D

2008-11-01

We report interparticle interactions effects on the magnetic structure of the surface region in Fe3O4 nanoparticles. For that, we have studied a desirable system composed by Fe3O4 nanoparticles with (d) = 9.3 nm and a narrow size distribution. These particles present an interesting morphology constituted by a crystalline core and a broad (approximately 50% vol.) disordered superficial shell. Two samples were prepared with distinct concentrations of the particles: weakly-interacting particles dispersed in a polymer and strongly-dipolar-interacting particles in a powder sample. M(H, T) measurements clearly show that strong dipolar interparticle interaction modifies the magnetic structure of the structurally disordered superficial shell. Consequently, we have observed drastically distinct thermal behaviours of magnetization and susceptibility comparing weakly- and strongly-interacting samples for the temperature range 2 K < T < 300 K. We have also observed a temperature-field dependence of the hysteresis loops of the dispersed sample that is not observed in the hysteresis loops of the powder one.

Phylogenetic Reassessment of Antarctic Tetillidae (Demospongiae, Tetractinellida) Reveals New Genera and Genetic Similarity among Morphologically Distinct Species

PubMed Central

Carella, Mirco; Agell, Gemma; Cárdenas, Paco; Uriz, Maria J.

2016-01-01

Species of Tetillidae are distributed worldwide. However, some genera are unresolved and only a few genera and species of this family have been described from the Antarctic. The incorporation of 25 new COI and 18S sequences of Antarctic Tetillidae to those used recently for assessing the genera phylogeny, has allowed us to improve the resolution of some poorly resolved nodes and to confirm the monophyly of previously identified clades. Classical genera such as Craniella recovered their traditional diagnosis by moving the Antarctic Tetilla from Craniella, where they were placed in the previous family phylogeny, to Antarctotetilla gen. nov. The morphological re-examination of specimens used in the previous phylogeny and their comparison to the type material revealed misidentifications. The proposed monotypic new genus Levantinella had uncertain phylogenetic relationships depending on the gene partition used. Two more clades would require the inclusion of additional species to be formally established as new genera. The parsimony tree based on morphological characters and the secondary structure of the 18S (V4 region) almost completely matched the COI M1-M6 and the COI+18S concatenated phylogenies. Morphological synapomorphies have been identified for the genera proposed. New 15 28S (D3-D5) and 11 COI I3-M11 partitions were exclusively sequenced for the Antarctic species subset. Remarkably, species within the Antarctic genera Cinachyra (C. barbata and C. antarctica) and Antarctotetilla (A. leptoderma, A. grandis, and A. sagitta), which are clearly distinguishable morphologically, were not genetically differentiated with any of the markers assayed. Thus, as it has been reported for other Antarctic sponges, both the mitochondrial and nuclear partitions used did not differentiate species that were well characterized morphologically. Antarctic Tetillidae offers a rare example of genetically cryptic (with the traditional markers used for sponges), morphologically distinct species. PMID:27557130

Modeling the characteristic etch morphologies along specific crystallographic orientations by anisotropic chemical etching

NASA Astrophysics Data System (ADS)

Li, Kun-Dar; Miao, Jin-Ru

2018-02-01

To improve the advanced manufacturing technology for functional materials, a sophisticated control of chemical etching process is highly demanded, especially in the fields of environment and energy related applications. In this study, a phase-field-based model is utilized to investigate the etch morphologies influenced by the crystallographic characters during anisotropic chemical etching. Three types of etching modes are inspected theoretically, including the isotropic, <100> and <111> preferred oriented etchings. Owing to the specific etching behavior along the crystallographic directions, different characteristic surface structures are presented in the simulations, such as the pimple-like, pyramidal hillock and ridge-like morphologies. In addition, the processing parameters affecting the surface morphological formation and evolution are also examined systematically. According to the numerical results, the growth mechanism of surface morphology in a chemical etching is revealed distinctly. While the etching dynamics plays a dominant role on the surface formation, the characteristic surface morphologies corresponding to the preferred etching direction become more apparent. As the atomic diffusion turned into a determinative factor, a smoothened surface would appear, even under the anisotropic etching conditions. These simulation results provide fundamental information to enhance the development and application of anisotropic chemical etching techniques.

Phylogenetic mapping of bacterial morphology

NASA Technical Reports Server (NTRS)

Siefert, J. L.; Fox, G. E.

1998-01-01

The availability of a meaningful molecular phylogeny for bacteria provides a context for examining the historical significance of various developments in bacterial evolution. Herein, the classical morphological descriptions of selected members of the domain Bacteria are mapped upon the genealogical ancestry deduced from comparison of small-subunit rRNA sequences. For the species examined in this study, a distinct pattern emerges which indicates that the coccus shape has arisen and accumulated independently multiple times in separate lineages and typically survived as a persistent end-state morphology. At least two other morphologies persist but have evolved only once. This study demonstrates that although bacterial morphology is not useful in defining bacterial phylogeny, it is remarkably consistent with that phylogeny once it is known. An examination of the experimental evidence available for morphogenesis as well as microbial fossil evidence corroborates these findings. It is proposed that the accumulation of persistent morphologies is a result of the biophysical properties of peptidoglycan and their genetic control, and that an evolved body-plan strategy based on peptidoglycan may have been a fate-sealing step in the evolution of Bacteria. More generally, this study illustrates that significant evolutionary insights can be obtained by examining biological and biochemical data in the context of a reliable phylogenetic structure.

Use of a Novel Two Color PALM Method to Examine Structural Properties of Drp1 Helical Rings during Mammalian Mitochondrial Fission In Situ

NASA Astrophysics Data System (ADS)

Rosenbloom, Alyssa Blair

In this thesis, we accomplish two goals: 1) we develop a novel two color photoactivatable light microscopy (PALM) method for imaging in mammalian cells and 2) we explore our original biological question and discern the structural properties of the Drp1 helical ring during fission. We established that mitochondrial membranes can be distinguished with the available photoactivatable fluorescent protein mEos2. However, we were not able to use any of the published photoactivatable and photoswitchable green fluorescent proteins, predominantly because of an inability to identify individual fluorescent events due to rapidity of the photoswitiching. Based on published crystal structures, we created novel Dronpa variants with increasing steric hindrance around the chromophore, likely partially inhibiting the isomerization. We replaced Val157 with isoleucine, leucine, or phenyalanine. DronpaV157F showed no fluorescence and was discarded. DronpaV157I and DronpaV157L showed photoswitchable green fluorescence, with individual fluorescent events that were more easily discerned. DronpaV157L in particular had bright fluorescent events that were well separated when imaged in mammalian cells at 20 Hz. We named this new variant rsKame. Using PALM we successfully imaged rsKame expressed and localized to the mammalian mitochondrial inner membrane. With the novel photoswitchable fluorescent protein, rsKame, available, we returned to the development of a novel two color PALM method. We chose PAmCherry1 as the partner for rsKame since PAmCherry1 has distinct and well separated excitation/emission spectra from rsKame and is not activated by low 405 nm laser power density. We first imaged rsKame with 405 nm activation at (0.61 mW/mm2) and 488 nm activation/excitation (5.87 W/mm 2) to completion. We then imaged PAmCherry1 with increasing 405 nm activation (0.6-6.0 W/mm2) and 561 nm excitation (22 W/mm 2). With the novel PALM imaging method, we labeled the inner and outer mitochondrial membranes with large populations of membrane bound rsKame and PAmCherry1 in HeLa and EpH4 cells. We were able to observe and clearly differentiate the two mitochondrial membrane structures and their various morphologies in situ. With the functional two-color PALM method, we returned to our original investigation of the Drp1 fission ring in situ. In fixed HeLa cells, we continued to label the outer membrane with PAmCherry1 and fused rsKame to the N-terminus of Drp1, separated by a linker. The resultant PALM images allowed for the observation of two previously observed and one hitherto unseen distinct Drp1 morphologies: Constrict, Terminal, and Split. The Constrict morphology was defined as the Drp1 structures that clearly encircle the mitochondrial tubule at various stages of membrane constriction. The Terminal morphology was defined as the Drp1 structures found at the termini of mitochondria, presumably post membrane scission. The Split morphology is a novel morphology and was defined as two Drp1 foci flanking the mitochondrial tubule but not completely encircling it. Quantification of the diameter and length of the Drp1 helical ring structures showed that the mean length of the Drp1 helical rings was consistent between all three morphologies, though a slight decrease was observed for the Terminal morphology, likely due to degradation. We observed a decrease of approximately 40 nm between the Constrict and Terminal mean diameters, consistent with a dynamic change in the Drp1 ring size due to membrane constriction towards membrane scission during mitochondrial fission. The Split morphology had a wide distribution of diameters and warrants further study. (Abstract shortened by UMI.)

A non-toxigenic but morphologically and phylogenetically distinct new species of Pseudo-nitzschia, P. sabit sp. nov. (Bacillariophyceae).

PubMed

Teng, Sing Tung; Lim, Po Teen; Lim, Hong Chang; Rivera-Vilarelle, María; Quijano-Scheggia, Sonia; Takata, Yoshinobu; Quilliam, Michael A; Wolf, Matthias; Bates, Stephen S; Leaw, Chui Pin

2015-08-01

A new species of Pseudo-nitzschia (Bacillariophyceae) is described from plankton samples collected from Port Dickson (Malacca Strait, Malaysia) and Manzanillo Bay (Colima, Mexico). The species possesses a distinctive falcate cell valve, from which they form sickle-like colonies in both environmental samples and cultured strains. Detailed observation of frustules under TEM revealed ultrastructure that closely resembles P. decipiens, yet the new species differs by the valve shape and greater ranges of striae and poroid densities. The species is readily distinguished from the curve-shaped P. subcurvata by the presence of a central interspace. The morphological distinction is further supported by phylogenetic discrimination. We sequenced and analyzed the nuclear ribosomal RNA genes in the LSU and the second internal transcribed spacer, including its secondary structure, to infer the phylogenetic relationship of the new species with its closest relatives. The results revealed a distinct lineage of the new species, forming a sister cluster with its related species, P. decipiens and P. galaxiae, but not with P. subcurvata. We examined the domoic acid (DA) production of five cultured strains from Malaysia by Liquid chromatography-mass spectrometry (LC-MS), but they showed no detectable DA. Here, we present the taxonomic description of the vegetative cells, document the sexual reproduction, and detail the molecular phylogenetics of Pseudo-nitzschia sabit sp. nov. © 2015 Phycological Society of America.

In situ 3-D mapping of pore structures and hollow grains of interplanetary dust particles with phase contrast X-ray nanotomography

NASA Astrophysics Data System (ADS)

Hu, Z. W.; Winarski, R. P.

2016-09-01

Unlocking the 3-D structure and properties of intact chondritic porous interplanetary dust particles (IDPs) in nanoscale detail is challenging, which is also complicated by atmospheric entry heating, but is important for advancing our understanding of the formation and origins of IDPs and planetary bodies as well as dust and ice agglomeration in the outer protoplanetary disk. Here, we show that indigenous pores, pristine grains, and thermal alteration products throughout intact particles can be noninvasively visualized and distinguished morphologically and microstructurally in 3-D detail down to ~10 nm by exploiting phase contrast X-ray nanotomography. We have uncovered the surprisingly intricate, submicron, and nanoscale pore structures of a ~10-μm-long porous IDP, consisting of two types of voids that are interconnected in 3-D space. One is morphologically primitive and mostly submicron-sized intergranular voids that are ubiquitous; the other is morphologically advanced and well-defined intragranular nanoholes that run through the approximate centers of ~0.3 μm or lower submicron hollow grains. The distinct hollow grains exhibit complex 3-D morphologies but in 2-D projections resemble typical organic hollow globules observed by transmission electron microscopy. The particle, with its outer region characterized by rough vesicular structures due to thermal alteration, has turned out to be an inherently fragile and intricately submicron- and nanoporous aggregate of the sub-μm grains or grain clumps that are delicately bound together frequently with little grain-to-grain contact in 3-D space.

Discrete element simulations of gravitational volcanic deformation. 1; Deformation structures and geometries

NASA Technical Reports Server (NTRS)

Morgan, Julia K.; McGovern, Patrick J.

2005-01-01

We have carried out two-dimensional particle dynamics simulations of granular piles subject to frictional Coulomb failure criteria to gain a first-order understanding of different modes of gravitational deformation within volcanoes. Under uniform basal and internal strength conditions, granular piles grow self-similarly, developing distinctive stratigraphies, morphologies, and structures. Piles constructed upon cohesive substrates exhibit particle avalanching, forming outward dipping strata and angle of repose slopes. Systematic decreases in basal strength lead to progressively deeper and steeper internal detachment faults and slip along a basal decollement; landslide forms grade from shallow slumps to deep-seated landslide and, finally, to axial subsidence and outward flank displacements, or volcanic spreading. Surface slopes decrease and develop concave up morphologies with decreasing decollement strength; depositional layers tilt progressively inward. Spatial variations in basal strength cause lateral transitions in pile structure, stratigraphy, and morphology. This approximation of volcanoes as Coulomb granular piles reproduces the richness of deformational structures and surface morphologies in many volcanic settings. The gentle slopes of Hawaiian volcanoes and Olympus Mons on Mars suggest weak basal decollements that enable volcanic spreading. High-angle normal faults, favored above weak decollements, are interpreted in both settings and may explain catastrophic sector collapse in Hawaii and broad aureole deposits surrounding Olympus Mons. In contrast, steeper slopes and shallow detachment faults predominate in the Canary Islands, thought to lack a weak decollement, favoring smaller, more frequent slope failures than predicted for Hawaii. The numerical results provide a useful predictive tool for interpreting dynamic behavior and associated geologic hazards of active volcanoes.

A dysmorphology score system for assessing embryo abnormalities in rat whole embryo culture.

PubMed

Zhang, Cindy X; Danberry, Tracy; Jacobs, Mary Ann; Augustine-Rauch, Karen

2010-12-01

The rodent whole embryo culture (WEC) system is a well-established model for characterizing developmental toxicity of test compounds and conducting mechanistic studies. Laboratories have taken various approaches in describing type and severity of developmental findings of organogenesis-stage rodent embryos, but the Brown and Fabro morphological score system is commonly used as a quantitative approach. The associated score criteria is based upon developmental stage and growth parameters, where a series of embryonic structures are assessed and assigned respective scores relative to their gestational stage, with a Total Morphological Score (TMS) assigned to the embryo. This score system is beneficial because it assesses a series of stage-specific anatomical landmarks, facilitating harmonized evaluation across laboratories. Although the TMS provides a quantitative approach to assess growth and determine developmental delay, it is limited to its ability to identify and/or delineate subtle or structure-specific abnormalities. Because of this, the TMS may not be sufficiently sensitive for identifying compounds that induce structure or organ-selective effects. This study describes a distinct morphological score system called the "Dysmorphology Score System (DMS system)" that has been developed for assessing gestation day 11 (approximately 20-26 somite stage) rat embryos using numerical scores to differentiate normal from abnormal morphology and define the respective severity of dysmorphology of specific embryonic structures and organ systems. This method can also be used in scoring mouse embryos of the equivalent developmental stage. The DMS system enhances capabilities to rank-order compounds based upon teratogenic potency, conduct structure- relationships of chemicals, and develop statistical prediction models to support abbreviated developmental toxicity screens. © 2010 Wiley-Liss, Inc.

Phylogeny of the order Choreotrichida (Ciliophora, Spirotricha, Oligotrichea) as inferred from morphology, ultrastructure, ontogenesis, and SSrRNA gene sequences

PubMed Central

Agatha, Sabine; Strüder-Kypke, Michaela C.

2010-01-01

The phylogeny within the order Choreotrichida is reconstructed using (i) morphologic, ontogenetic, and ultrastructural evidence for the cladistic approach and (ii) the small subunit ribosomal RNA (SSrRNA) gene sequences, including the new sequence of Rimostrombidium lacustris. The morphologic cladograms and the gene trees converge rather well for the Choreotrichida, demonstrating that hyaline and agglutinated loricae do not characterize distinct lineages, i.e., both lorica types can be associated with the most highly developed ciliary pattern. The position of Rimostrombidium lacustris within the family Strobilidiidae is corroborated by the genealogical analyses. The diagnosis of the genus Tintinnidium is improved, adding cytological features, and the genus is divided into two subgenera based on the structure of the somatic kineties. The diagnosis of the family Lohmanniellidae and the genus Lohmanniella are improved, and Rimostrombidium glacicolum​ Petz, Song and Wilbert, 1995 is affiliated. PMID:17166704

The hidden anatomy of paranasal sinuses reveals biogeographically distinct morphotypes in the nine-banded armadillo (Dasypus novemcinctus).

PubMed

Billet, Guillaume; Hautier, Lionel; de Thoisy, Benoit; Delsuc, Frédéric

2017-01-01

With their Pan-American distribution, long-nosed armadillos (genus Dasypus ) constitute an understudied model for Neotropical biogeography. This genus currently comprises seven recognized species, the nine-banded armadillo ( D. novemcinctus ) having the widest distribution ranging from Northern Argentina to the South-Eastern US. With their broad diversity of habitats, nine-banded armadillos provide a useful model to explore the effects of climatic and biogeographic events on morphological diversity at a continental scale. Based on a sample of 136 skulls of Dasypus spp. belonging to six species, including 112 specimens identified as D. novemcinctus , we studied the diversity and pattern of variation of paranasal cavities, which were reconstructed virtually using µCT-scanning or observed through bone transparency. Our qualitative analyses of paranasal sinuses and recesses successfully retrieved a taxonomic differentiation between the traditional species D. kappleri , D. pilosus and D. novemcinctus but failed to recover diagnostic features between the disputed and morphologically similar D. septemcinctus and D. hybridus . Most interestingly, the high variation detected in our large sample of D. novemcinctus showed a clear geographical patterning, with the recognition of three well-separated morphotypes: one ranging from North and Central America and parts of northern South America west of the Andes, one distributed across the Amazonian Basin and central South America, and one restricted to the Guiana Shield. The question as to whether these paranasal morphotypes may represent previously unrecognized species is to be evaluated through a thorough revision of the Dasypus species complex integrating molecular and morphological data. Remarkably, our recognition of a distinct morphotype in the Guiana Shield area is congruent with the recent discovery of a divergent mitogenomic lineage in French Guiana. The inflation of the second medialmost pair of caudal frontal sinuses constitutes an unexpected morphological diagnostic feature for this potentially distinct species. Our results demonstrate the benefits of studying overlooked internal morphological structures in supposedly cryptic species revealed by molecular data. It also illustrates the under-exploited potential of the highly variable paranasal sinuses of armadillos for systematic studies.

Plateau-Rayleigh Crystal Growth of Nanowire Heterostructures: Strain-Modified Surface Chemistry and Morphological Control in One, Two, and Three Dimensions.

PubMed

Day, Robert W; Mankin, Max N; Lieber, Charles M

2016-04-13

One-dimensional (1D) structures offer unique opportunities for materials synthesis since crystal phases and morphologies that are difficult or impossible to achieve in macroscopic crystals can be synthesized as 1D nanowires (NWs). Recently, we demonstrated one such phenomenon unique to growth on a 1D substrate, termed Plateau-Rayleigh (P-R) crystal growth, where periodic shells develop along a NW core to form diameter-modulated NW homostructures with tunable morphologies. Here we report a novel extension of the P-R crystal growth concept with the synthesis of heterostructures in which Ge (Si) is deposited on Si (Ge) 1D cores to generate complex NW morphologies in 1, 2, or 3D. Depositing Ge on 50 nm Si cores with a constant GeH4 pressure yields a single set of periodic shells, while sequential variation of GeH4 pressure can yield multimodulated 1D NWs with two distinct sets of shell periodicities. P-R crystal growth on 30 nm cores also produces 2D loop structures, where Ge (Si) shells lie primarily on the outside (inside) of a highly curved Si (Ge) core. Systematic investigation of shell morphology as a function of growth time indicates that Ge shells grow in length along positive curvature Si cores faster than along straight Si cores by an order of magnitude. Short Ge deposition times reveal that shells develop on opposite sides of 50 and 100 nm Si cores to form straight 1D morphologies but that shells develop on the same side of 20 nm cores to produce 2D loop and 3D spring structures. These results suggest that strain mediates the formation of 2 and 3D morphologies by altering the NW's surface chemistry and that surface diffusion of heteroatoms on flexible freestanding 1D substrates can facilitate this strain-mediated mechanism.

Variability and similarities in the structural properties of two related Laminaria kelp species

NASA Astrophysics Data System (ADS)

Henry, Pierre-Yves

2018-01-01

Kelps of the genus Laminaria have long been studied and shown to exhibit a seasonal shift in growth and morphology, as nutrients and light levels change during the year. However, the variation of kelp biomechanical properties has been little explored despite the importance of these properties for the interaction of kelp with the flow. Previous research showed that aging does influence the algae biomechanical properties, so this study further investigates the variability of kelp biomechanical properties and morphological characteristics at a given site as a function of the season (growth phase), species, and different kelp parts. Mechanical parameters and morphological characteristics were measured on kelps sampled in winter and summer, and DNA sequencing was used to identify the two related species, L. digitata and L. hyperborea. Descriptive statistics and statistical analysis were used to detect trends in the modulation of kelp mechanical design. Although two distinct species were identified, only minor structural differences were observed between them. The biomechanical properties varied significantly along the kelp, and significant seasonal shifts occurred at the blade level, in relation to the different morphological changes during blade renewal. In general, the variations of the structural properties were mostly linked to the blade growth activity. The absence of significant variation in the mechanical design of the two species highlights the significance of the adaptation to the same local environmental conditions, this adaptation being a key process in vegetation-flow interactions and having implications on the interaction between kelp and hydrodynamics.

Gross morphology and histology of the alimentary tract of the convict cichlid Amatitlania nigrofasciata.

PubMed

Hopperdietzel, C; Hirschberg, R M; Hünigen, H; Wolter, J; Richardson, K; Plendl, J

2014-11-01

The primary objectives of this study were to document the macroscopic and histological structure of the alimentary tract (AT) of the convict cichlid Amatitlania nigrofasciata, because there are no data available for this omnivorous freshwater fish of the family Cichlidae. The morphology of the AT of A. nigrofasciata resembles that of related species. While having morphological criteria of the AT typical of most omnivorous fishes, such as a blind sac stomach and medium length intestine, A. nigrofasciata also has some structural peculiarities: the oesophagus is lined by a uniform stratified squamous epithelial layer with interspersed goblet cells along its entire length. Additionally, it has well-developed layers of the tunica muscularis including muscle fibre bundles that ascend into its mucosal folds. Occasionally, taste buds are present. In the transitional area between oesophagus and stomach, a prominent torus-like closure device is present. The mucosa of the stomach cannot be divided into different regions according to mucosal and morphological properties. The simple pattern of intestinal loops of A. nigrofasciata has few variations, irrespective of sex, mass and length of the individual fish. The first segment of the intestine is characterized by the largest mucososerosal ratio and the most complex mucosal surface architecture. A distinction of midgut and hindgut was not possible in A. nigrofasciata due to lack of defining structural components as described for other fish species. © 2014 The Fisheries Society of the British Isles.

Geographical genetic structuring and phenotypic variation in the Vellozia hirsuta (Velloziaceae) ochlospecies complex.

PubMed

Barbosa, Ariane R; Fiorini, Cecília F; Silva-Pereira, Viviane; Mello-Silva, Renato; Borba, Eduardo L

2012-09-01

Vellozia hirsuta forms a complex presenting wide morphological and anatomical variation, resulting in five specific names and 14 morpho-anatomical patterns occurring in disjunct populations. We carried out a phylogeographical study to investigate the existence of correlation among the genetic and morphological patterns within this complex, and to determine whether it is composed of various species or should be treated as an ochlospecies, a species having widely polymorphic and weakly polytypic complex variation, with morphological characteristics varying independently. We carried out phylogeographical analyses using cpDNA rpl32F-trnL intergenic region. We found 20 haplotypes in 23 populations sampled. The populations are genetically structured (Φ(ST) = 0.818) into four phylogeographical groups demonstrating geographical structuring but with no correlation with morpho-anatomical patterns. Our analyses do not support recognizing any of the species now synonymized under Vellozia hirsuta. The northern populations were the most genetically differentiated and could be considered a distinct taxon, as they are also morphologically different. It is recommended that Vellozia hirsuta be considered a single enormously variable species. The patterns of variation within V. hirsuta probably are related to climatic changes that occurred during the Pleistocene Epoch in tropical Brazil when reductions in forest cover favored the expansion of V. hirsuta populations into extensive lowland areas. The expansion of forest cover at the end of the glaciations would have again restricted the occurrence of campos rupestres vegetation to high elevations, which constitute the current centers of diversity of this species.

Arabic morphology in the neural language system.

PubMed

Boudelaa, Sami; Pulvermüller, Friedemann; Hauk, Olaf; Shtyrov, Yury; Marslen-Wilson, William

2010-05-01

There are two views about morphology, the aspect of language concerned with the internal structure of words. One view holds that morphology is a domain of knowledge with a specific type of neurocognitive representation supported by specific brain mechanisms lateralized to left fronto-temporal cortex. The alternate view characterizes morphological effects as being a by-product of the correlation between form and meaning and where no brain area is predicted to subserve morphological processing per se. Here we provided evidence from Arabic that morphemes do have specific memory traces, which differ as a function of their functional properties. In an MMN study, we showed that the abstract consonantal root, which conveys semantic meaning (similarly to monomorphemic content words in English), elicits an MMN starting from 160 msec after the deviation point, whereas the abstract vocalic word pattern, which plays a range of grammatical roles, elicits an MMN response starting from 250 msec after the deviation point. Topographically, the root MMN has a symmetric fronto-central distribution, whereas the word pattern MMN lateralizes significantly to the left, indicating stronger involvement of left peri-sylvian areas. In languages with rich morphologies, morphemic processing seems to be supported by distinct neural networks, thereby providing evidence for a specific neuronal basis for morphology as part of the cerebral language machinery.

Pineal organs of deep-sea fish: photopigments and structure.

PubMed

Bowmaker, James K; Wagner, Hans-Joachim

2004-06-01

We have examined the morphology and photopigments of the pineal organs from a number of mesopelagic fish, including representatives of the hatchet fish (Sternoptychidae), scaly dragon-fish (Chauliodontidae) and bristlemouths (Gonostomidae). Although these fish were caught at depths of between 500 and 1000 m, the morphological organisation of their pineal organs is remarkably similar to that of surface-dwelling fish. Photoreceptor inner and outer segments protrude into the lumen of the pineal vesicle, and the outer segment is composed of a stack of up to 20 curved disks that form a cap-like cover over the inner segment. In all species, the pineal photopigment was spectrally distinct from the retinal rod pigment, with lambdamax displaced to longer wavelengths, between approximately 485 and 503 nm. We also investigated the pineal organ of the deep demersal eel, Synaphobranchus kaupi, caught at depths below 2000 m, which possesses a rod visual pigment with lambdamax at 478 nm, but the pineal pigment has lambdamax at approximately 515 nm. In one species of hatchet fish, Argyropelecus affinis, two spectral classes of pinealocyte were identified, both spectrally distinct from the retinal rod photopigment.

Recognition of the genus Thaumatophyllum Schott − formerly Philodendron subg. Meconostigma (Araceae) − based on molecular and morphological evidence

PubMed Central

Sakuragui, Cassia Mônica; Calazans, Luana Silva Braucks; de Oliveira, Leticia Loss; de Morais, Érica Barroso; Benko-Iseppon, Ana Maria; Vasconcelos, Santelmo; Schrago, Carlos Eduardo Guerra; Mayo, Simon Joseph

2018-01-01

Abstract Philodendron subgenus Meconostigma has been a well-circumscribed group since 1829. Members of this group are easily distinguished by diagnostic morphological characters as well as by a distinct ecology and geographical distribution. Based on molecular, morphological and cytological evidence, we propose the recognition of P. subg. Meconostigma as a distinct genus, Thaumatophyllum Schott. We also present the necessary new combinations, an emended key and some nomenclatural and taxonomic corrections regarding 21 names of Thaumatophyllum. PMID:29750071

Distinction of Fly Artifacts from Human Blood using Immunodetection.

PubMed

Rivers, David B; Acca, Gillian; Fink, Marc; Brogan, Rebecca; Chen, Dorothy; Schoeffield, Andrew

2018-02-21

Insect stains produced by necrophagous flies are indistinguishable morphologically from human bloodstains. At present, no diagnostic tests exist to overcome this deficiency. As the first step toward developing a chemical test to recognize fly artifacts, polyclonal antisera were generated in rats against three distinct antigenic sequences of fly cathepsin D-like proteinase, an enzyme that is structurally distinct in cyclorrhaphous Diptera from other animals. The resulting rat antisera bound to artifacts produced by Protophormia terraenovae and synthetic peptides used to generate the polyclonal antisera, but not with any type of mammalian blood tested in immunoassays. Among the three antisera, anti-md3 serum displayed the highest reactivity for fly stains, demonstrated cross-reactivity for all synthetic peptides representing antigenic sequences of the mature fly enzyme, and bound artifacts originating from the fly digestive tract. Further work is needed to determine whether the antisera are suitable for non-laboratory conditions. © 2018 American Academy of Forensic Sciences.

Characterization of Cell Surface and EPS Remodeling of Azospirillum brasilense Chemotaxis-like 1 Signal Transduction Pathway mutants by Atomic Force Microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Billings, Amanda N; Siuti, Piro; Bible, Amber

2011-01-01

To compete in complex microbial communities, bacteria must quickly sense environmental changes and adjust cellular functions for optimal growth. Chemotaxis-like signal transduction pathways are implicated in the modulation of multiple cellular responses, including motility, EPS production, and cell-to-cell interactions. Recently, the Che1 chemotaxis-like pathway from Azospirillum brasilense was shown to modulate flocculation. In A. brasilense, cell surface properties, including EPS production, are thought to play a direct role in promoting flocculation. Using atomic force microscopy (AFM), we have detected distinct changes in the surface morphology of flocculating A. brasilense Che1 mutant strains that are absent in the wild type strain.more » Whereas the wild type strain produces a smooth mucosal extracellular matrix, the flocculating Che1 mutant strains produce distinctive extracellular fibril structures. Further analyses using flocculation inhibition and lectin-binding assays suggest that the composition of EPS components in the extracellular matrix differs between the cheA1 and cheY1 mutants, despite an apparent similarity in the macroscopic floc structures. Collectively, these data indicate that mutations in the Che1 pathway that result in increased flocculation are correlated with distinctive changes in the extracellular matrix structure produced by the mutants, including likely changes in the EPS structure and/or composition.« less

The lid wiper and muco-cutaneous junction anatomy of the human eyelid margins: an in vivo confocal and histological study

PubMed Central

Knop, Erich; Knop, Nadja; Zhivov, Andrey; Kraak, Robert; Korb, Donald R; Blackie, Caroline; Greiner, Jack V; Guthoff, Rudolf

2011-01-01

The inner border of the eyelid margin is critically important for ocular surface integrity because it guarantees the thin spread of the tear film. Its exact morphology in the human is still insufficiently known. The histology in serial sections of upper and lower lid margins in whole-mount specimens from 10 human body donors was compared to in vivo confocal microscopy of eight eyes with a Heidelberg retina-tomograph (HRT II) and attached Rostock cornea module. Behind the posterior margin of the Meibomian orifices, the cornified epidermis stopped abruptly and was replaced by a continuous layer of para-keratinized (pk) cells followed by discontinuous pk cells. The pk cells covered the muco-cutaneous junction (MCJ), the surface of which corresponded to the line of Marx (0.2–0.3 mm wide). Then a stratified epithelium with a conjunctival structure of cuboidal cells, some pk cells, and goblet cells formed an epithelial elevation of typically about 100 μm initial thickness (lid wiper). This continued for 0.3–1.5 mm and formed a slope. The MCJ and lid wiper extended all along the lid margin from nasal to temporal positions in the upper and lower lids. Details of the epithelium and connective tissue were also detectable using the Rostock cornea module. The human inner lid border has distinct zones. Due to its location and morphology, the epithelial lip of the lid wiper appears a suitable structure to spread the tear film and is distinct from the MCJ/line of Marx. Better knowledge of the lid margin appears important for understanding dry eye disease and its morphology can be analysed clinically by in vivo confocal microscopy. PMID:21413985

Aggregates and Superaggregates of Soot with Four Distinct Fractal Morphologies

NASA Technical Reports Server (NTRS)

Sorensen, C. M.; Kim, W.; Fry, D.; Chakrabarti, A.

2004-01-01

Soot formed in laminar diffusion flames of heavily sooting fuels evolves through four distinct growth stages which give rise to four distinct aggregate fractal morphologies. These results were inferred from large and small angle static light scattering from the flames, microphotography of the flames, and analysis of soot sampled from the flames. The growth stages occur approximately over four successive orders of magnitude in aggregate size. Comparison to computer simulations suggests that these four growth stages involve either diffusion limited cluster aggregation or percolation in either three or two dimensions.

Beyond neutral and forbidden links: morphological matches and the assembly of mutualistic hawkmoth-plant networks.

PubMed

Sazatornil, Federico D; Moré, Marcela; Benitez-Vieyra, Santiago; Cocucci, Andrea A; Kitching, Ian J; Schlumpberger, Boris O; Oliveira, Paulo E; Sazima, Marlies; Amorim, Felipe W

2016-11-01

A major challenge in evolutionary ecology is to understand how co-evolutionary processes shape patterns of interactions between species at community level. Pollination of flowers with long corolla tubes by long-tongued hawkmoths has been invoked as a showcase model of co-evolution. Recently, optimal foraging models have predicted that there might be a close association between mouthparts' length and the corolla depth of the visited flowers, thus favouring trait convergence and specialization at community level. Here, we assessed whether hawkmoths more frequently pollinate plants with floral tube lengths similar to their proboscis lengths (morphological match hypothesis) against abundance-based processes (neutral hypothesis) and ecological trait mismatches constraints (forbidden links hypothesis), and how these processes structure hawkmoth-plant mutualistic networks from five communities in four biogeographical regions of South America. We found convergence in morphological traits across the five communities and that the distribution of morphological differences between hawkmoths and plants is consistent with expectations under the morphological match hypothesis in three of the five communities. In the two remaining communities, which are ecotones between two distinct biogeographical areas, interactions are better predicted by the neutral hypothesis. Our findings are consistent with the idea that diffuse co-evolution drives the evolution of extremely long proboscises and flower tubes, and highlight the importance of morphological traits, beyond the forbidden links hypothesis, in structuring interactions between mutualistic partners, revealing that the role of niche-based processes can be much more complex than previously known. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

In situ observations of a high-pressure phase of H2O ice

USGS Publications Warehouse

Chou, I.-Ming; Blank, J.G.; Goncharov, A.F.; Mao, Ho-kwang; Hemley, R.J.

1998-01-01

A previously unknown solid phase of H2O has been identified by its peculiar growth patterns, distinct pressure-temperature melting relations, and vibrational Raman spectra. Morphologies of ice crystals and their pressure-temperature melting relations were directly observed in a hydrothermal diamond-anvil cell for H2O bulk densities between 1203 and 1257 kilograms per cubic meter at temperatures between -10??and 50??C. Under these conditions, four different ice forms were observed to melt: two stable phases, ice V and ice VI, and two metastable phases, ice IV and the new ice phase. The Raman spectra and crystal morphology are consistent with a disordered anisotropic structure with some similarities to ice VI.

Secular Evolution in Barred Galaxies: Observations

NASA Astrophysics Data System (ADS)

Merrifield, M.

2002-12-01

This paper describes a framework for studying galaxy morphology, particularly bar strength, in a quantitative manner, and presents applications of this approach that reveal observational evidence for secular evolution in bar morphology. The distribution of bar strength in galaxies is quite strongly bimodal, suggesting that barred and unbarred systems are distinct entities, and that any evolution between these two states must occur on a relatively rapid timescale. Bars' strengths appear to be correlated with their pattern speeds, implying that these structures weaken as they start to slow, and disappear entirely before the bars have slowed significantly. There is also tantalizing evidence that bars are rare beyond a redshift of z ~ 0.7, indicating that galaxies have only recently evolved to a point where bars can readily form.

Development of new smart materials and spinning systems inspired by natural silks and their applications

NASA Astrophysics Data System (ADS)

Cheng, Jie; Lee, Sang-Hoon

2015-12-01

Silks produced by spiders and silkworms are charming natural biological materials with highly optimized hierarchical structures and outstanding physicomechanical properties. The superior performance of silks relies on the integration of a unique protein sequence, a distinctive spinning process, and complex hierarchical structures. Silks have been prepared to form a variety of morphologies and are widely used in diverse applications, for example, in the textile industry, as drug delivery vehicles, and as tissue engineering scaffolds. This review presents an overview of the organization of natural silks, in which chemical and physical functions are optimized, as well as a range of new materials inspired by the desire to mimic natural silk structure and synthesis.

Juvenile skeletogenesis in anciently diverged sea urchin clades.

PubMed

Gao, Feng; Thompson, Jeffrey R; Petsios, Elizabeth; Erkenbrack, Eric; Moats, Rex A; Bottjer, David J; Davidson, Eric H

2015-04-01

Mechanistic understanding of evolutionary divergence in animal body plans devolves from analysis of those developmental processes that, in forms descendant from a common ancestor, are responsible for their morphological differences. The last common ancestor of the two extant subclasses of sea urchins, i.e., euechinoids and cidaroids, existed well before the Permian/Triassic extinction (252 mya). Subsequent evolutionary divergence of these clades offers in principle a rare opportunity to solve the developmental regulatory events underlying a defined evolutionary divergence process. Thus (i) there is an excellent and fairly dense (if yet incompletely analyzed) fossil record; (ii) cladistically confined features of the skeletal structures of modern euechinoid and cidaroid sea urchins are preserved in fossils of ancestral forms; (iii) euechinoids and cidaroids are among current laboratory model systems in molecular developmental biology (here Strongylocentrotus purpuratus [Sp] and Eucidaris tribuloides [Et]); (iv) skeletogenic specification in sea urchins is uncommonly well understood at the causal level of interactions of regulatory genes with one another, and with known skeletogenic effector genes, providing a ready arsenal of available molecular tools. Here we focus on differences in test and perignathic girdle skeletal morphology that distinguish all modern euechinoid from all modern cidaroid sea urchins. We demonstrate distinct canonical test and girdle morphologies in juveniles of both species by use of SEM and X-ray microtomography. Among the sharply distinct morphological features of these clades are the internal skeletal structures of the perignathic girdle to which attach homologous muscles utilized for retraction and protraction of Aristotles׳ lantern and its teeth. We demonstrate that these structures develop de novo between one and four weeks after metamorphosis. In order to study the underlying developmental processes, a method of section whole mount in situ hybridization was adapted. This method displays current gene expression in the developing test and perignathic girdle skeletal elements of both Sp and Et juveniles. Active, specific expression of the sm37 biomineralization gene in these muscle attachment structures accompanies morphogenetic development of these clade-specific features in juveniles of both species. Skeletogenesis at these clade-specific muscle attachment structures displays molecular earmarks of the well understood embryonic skeletogenic GRN: thus the upstream regulatory gene alx1 and the gene encoding the vegfR signaling receptor are both expressed at the sites where they are formed. This work opens the way to analysis of the alternative spatial specification processes that were installed at the evolutionary divergence of the two extant subclasses of sea urchins. Copyright © 2015 Elsevier Inc. All rights reserved.

Perspectives on the Growth of High Edge Density Carbon Nanostructures: Transitions from Vertically Oriented Graphene Nanosheets to Graphenated Carbon Nanotubes

PubMed Central

2015-01-01

Insights into the growth of high edge density carbon nanostructures were achieved by a systematic parametric study of plasma-enhanced chemical vapor deposition (PECVD). Such structures are important for electrode performance in a variety of applications such as supercapacitors, neural stimulation, and electrocatalysis. A morphological trend was observed as a function of temperature whereby graphenated carbon nanotubes (g-CNTs) emerged as an intermediate structure between carbon nanotubes (CNTs) at lower temperatures and vertically oriented carbon nanosheets (CNS), composed of few-layered graphene, at higher temperatures. This is the first time that three distinct morphologies and dimensionalities of carbon nanostructures (i.e., 1D CNTs, 2D CNSs, and 3D g-CNTs) have been synthesized in the same reaction chamber by varying only a single parameter (temperature). A design of experiments (DOE) approach was utilized to understand the range of growth permitted in a microwave PECVD reactor, with a focus on identifying graphenated carbon nanotube growth within the process space. Factors studied in the experimental design included temperature, gas ratio, catalyst thickness, pretreatment time, and deposition time. This procedure facilitates predicting and modeling high edge density carbon nanostructure characteristics under a complete range of growth conditions that yields various morphologies of nanoscale carbon. Aside from the morphological trends influenced by temperature, a relationship between deposition temperature and specific capacitance emerged from the DOE study. Transmission electron microscopy was also used to understand the morphology and microstructure of the various high edge density structures. From these results, a new graphene foliate formation mechanism is proposed for synthesis of g-CNTs in a single deposition process. PMID:25089165

Flow Structure and Channel Morphology at a Confluent-Meander Bend

NASA Astrophysics Data System (ADS)

Riley, J. D.; Rhoads, B. L.

2009-12-01

Flow structure and channel morphology in meander bends have been well documented. Channel curvature subjects flow through a bend to centrifugal acceleration, inducing a counterbalancing pressure-gradient force that initiates secondary circulation. Transverse variations in boundary shear stress and bedload transport parallel cross-stream movement of high velocity flow and determine spatial patterns of erosion along the outer bank and deposition along the inner bank. Laboratory experiments and numerical modeling of confluent-meander bends, a junction planform that develops when a tributary joins a meandering river along the outer bank of a bend, suggest that flow and channel morphology in such bends deviate from typical patterns. The purpose of this study is to examine three-dimensional (3-D) flow structure and channel morphology at a natural confluent-meander bend. Field data were collected in southeastern Illinois where Big Muddy Creek joins the Little Wabash River near a local maximum of curvature along an elongated meander loop. Measurements of 3-D velocity components were obtained with an acoustic Doppler current profiler (ADCP) for two flow events with differing momentum ratios. Channel bathymetry was also resolved from the four-beam depths of the ADCP. Analysis of velocity data reveals a distinct shear layer flanked by dual helical cells within the bend immediately downstream of the confluence. Flow from the tributary confines flow from the main channel along the inner part of the channel cross section, displacing the thalweg inward, limiting the downstream extent of the point bar, protecting the outer bank from erosion and enabling bar-building along this bank. Overall, this pattern of flow and channel morphology is quite different from typical patterns in meander bends, but is consistent with a conceptual model derived from laboratory experiments and numerical modeling.

Rates of morphological evolution, asymmetry and morphological integration of shell shape in scallops.

PubMed

Sherratt, Emma; Serb, Jeanne M; Adams, Dean C

2017-12-08

Rates of morphological evolution vary across different taxonomic groups, and this has been proposed as one of the main drivers for the great diversity of organisms on Earth. Of the extrinsic factors pertaining to this variation, ecological hypotheses feature prominently in observed differences in phenotypic evolutionary rates across lineages. But complex organisms are inherently modular, comprising distinct body parts that can be differentially affected by external selective pressures. Thus, the evolution of trait covariation and integration in modular systems may also play a prominent role in shaping patterns of phenotypic diversity. Here we investigate the role ecological diversity plays in morphological integration, and the tempo of shell shape evolution and of directional asymmetry in bivalved scallops. Overall, the shape of both valves and the magnitude of asymmetry of the whole shell (difference in shape between valves) are traits that are evolving fast in ecomorphs under strong selective pressures (gliders, recessers and nestling), compared to low rates observed in other ecomorphs (byssal-attaching, free-living and cementing). Given that different parts of an organism can be under different selective pressures from the environment, we also examined the degree of evolutionary integration between the valves as it relates to ecological shifts. We find that evolutionary morphological integration is consistent and surprisingly high across species, indicating that while the left and right valves of a scallop shell are diversifying in accordance with ecomorphology, they are doing so in a concerted fashion. Our study on scallops adds another strong piece of evidence that ecological shifts play an important role in the tempo and mode of morphological evolution. Strong selective pressures from the environment, inferred from the repeated evolution of distinct ecomorphs, have influenced the rate of morphological evolution in valve shape and the magnitude of asymmetry between valves. Our observation that morphological integration of the valves making up the shell is consistently strong suggests tight developmental pathways are responsible for the concerted evolution of these structures while environmental pressures are driving whole shell shape. Finally, our study shows that directional asymmetry in shell shape among species is an important aspect of scallop macroevolution.

A new caddisfly genus (Trichoptera, Odontoceridae) from Vietnam

PubMed Central

Arefina-Armitage, Tatiana I.; Armitage, Brian J.

2010-01-01

Abstract Cephalopsyche, a new genus of caddisfly (Trichoptera, Odontoceridae), is described from Vietnam. Two new species are placed in the genus: Cephalopsyche gorgona sp. n. and Cephalopsyche neboissi sp. n. The adult male and female of each species exhibit distinct sexual dimorphism, especially in head morphology. In males, there are hinged, chamber-like structures on the vertex of the head, containing filamentous, columnar tissue when exposed. Descriptions and illustrations of both species are provided. PMID:21594025

Two novel AGXT mutations identified in primary hyperoxaluria type-1 and distinct morphological and structural difference in kidney stones

PubMed Central

Wang, Cui; Lu, Jingru; Lang, Yanhua; Liu, Ting; Wang, Xiaoling; Zhao, Xiangzhong; Shao, Leping

2016-01-01

Primary hyperoxaluria type 1 (PH1) is a rare genetic disease characterized by excessive oxalate accumulation in plasma and urine, resulting in various phenotypes because of allelic and clinical heterogeneity. This study aimed to detect disease-associated genetic mutations in three PH1 patients in a Chinese family. All AGXT exons and 3 common polymorphisms which might synergistically interact with mutations, including P11L, I340 M and IVSI+74 bp were analyzed by direct sequencing in all family members. It demonstrated that in each of three patients, a previously reported nonsense mutation p.R333* was in cis with a novel missense mutation p.M49L in the minor allele characterized by the polymorphism of 74-bp duplication in intron 1, while the other novel missense mutation p.N72I was in trans with both p.R333* and P.M49L in the major allele. Kidney stones from two sibling patients were also observed though stereomicroscopic examination and scanning electron microscopy. Distinct morphological and inner-structure differences in calculi were noticed, suggesting clinical heterozygosity of PH1 to a certain extent. In brief, two novel missense mutations were identified probably in association with PH1, a finding which should provide an accurate tool for prenatal diagnosis, genetic counseling and screening for potential presymptomatic individuals. PMID:27644547

Two novel AGXT mutations identified in primary hyperoxaluria type-1 and distinct morphological and structural difference in kidney stones.

PubMed

Wang, Cui; Lu, Jingru; Lang, Yanhua; Liu, Ting; Wang, Xiaoling; Zhao, Xiangzhong; Shao, Leping

2016-09-20

Primary hyperoxaluria type 1 (PH1) is a rare genetic disease characterized by excessive oxalate accumulation in plasma and urine, resulting in various phenotypes because of allelic and clinical heterogeneity. This study aimed to detect disease-associated genetic mutations in three PH1 patients in a Chinese family. All AGXT exons and 3 common polymorphisms which might synergistically interact with mutations, including P11L, I340 M and IVSI+74 bp were analyzed by direct sequencing in all family members. It demonstrated that in each of three patients, a previously reported nonsense mutation p.R333(*) was in cis with a novel missense mutation p.M49L in the minor allele characterized by the polymorphism of 74-bp duplication in intron 1, while the other novel missense mutation p.N72I was in trans with both p.R333(*) and P.M49L in the major allele. Kidney stones from two sibling patients were also observed though stereomicroscopic examination and scanning electron microscopy. Distinct morphological and inner-structure differences in calculi were noticed, suggesting clinical heterozygosity of PH1 to a certain extent. In brief, two novel missense mutations were identified probably in association with PH1, a finding which should provide an accurate tool for prenatal diagnosis, genetic counseling and screening for potential presymptomatic individuals.

Physiological and structural differences in spatially distinct subpopulations of cardiac mitochondria: influence of cardiac pathologies

PubMed Central

Thapa, Dharendra; Shepherd, Danielle L.

2014-01-01

Cardiac tissue contains discrete pools of mitochondria that are characterized by their subcellular spatial arrangement. Subsarcolemmal mitochondria (SSM) exist below the cell membrane, interfibrillar mitochondria (IFM) reside in rows between the myofibrils, and perinuclear mitochondria are situated at the nuclear poles. Microstructural imaging of heart tissue coupled with the development of differential isolation techniques designed to sequentially separate spatially distinct mitochondrial subpopulations have revealed differences in morphological features including shape, absolute size, and internal cristae arrangement. These findings have been complemented by functional studies indicating differences in biochemical parameters and, potentially, functional roles for the ATP generated, based upon subcellular location. Consequently, mitochondrial subpopulations appear to be influenced differently during cardiac pathologies including ischemia/reperfusion, heart failure, aging, exercise, and diabetes mellitus. These influences may be the result of specific structural and functional disparities between mitochondrial subpopulations such that the stress elicited by a given cardiac insult differentially impacts subcellular locales and the mitochondria contained within. The goal of this review is to highlight some of the inherent structural and functional differences that exist between spatially distinct cardiac mitochondrial subpopulations as well as provide an overview of the differential impact of various cardiac pathologies on spatially distinct mitochondrial subpopulations. As an outcome, we will instill a basis for incorporating subcellular spatial location when evaluating the impact of cardiac pathologies on the mitochondrion. Incorporation of subcellular spatial location may offer the greatest potential for delineating the influence of cardiac pathology on this critical organelle. PMID:24778166

Articular soft tissue anatomy of the archosaur hip joint: Structural homology and functional implications.

PubMed

Tsai, Henry P; Holliday, Casey M

2015-06-01

Archosaurs evolved a wide diversity of locomotor postures, body sizes, and hip joint morphologies. The two extant archosaurs clades (birds and crocodylians) possess highly divergent hip joint morphologies, and the homologies and functions of their articular soft tissues, such as ligaments, cartilage, and tendons, are poorly understood. Reconstructing joint anatomy and function of extinct vertebrates is critical to understanding their posture, locomotor behavior, ecology, and evolution. However, the lack of soft tissues in fossil taxa makes accurate inferences of joint function difficult. Here, we describe the soft tissue anatomies and their osteological correlates in the hip joint of archosaurs and their sauropsid outgroups, and infer structural homology across the extant taxa. A comparative sample of 35 species of birds, crocodylians, lepidosaurs, and turtles ranging from hatchling to skeletally mature adult were studied using dissection, imaging, and histology. Birds and crocodylians possess topologically and histologically consistent articular soft tissues in their hip joints. Epiphyseal cartilages, fibrocartilages, and ligaments leave consistent osteological correlates. The archosaur acetabulum possesses distinct labrum and antitrochanter structures on the supraacetabulum. The ligamentum capitis femoris consists of distinct pubic- and ischial attachments, and is homologous with the ventral capsular ligament of lepidosaurs. The proximal femur has a hyaline cartilage core attached to the metaphysis via a fibrocartilaginous sleeve. This study provides new insight into soft tissue structures and their osteological correlates (e.g., the antitrochanter, the fovea capitis, and the metaphyseal collar) in the archosaur hip joint. The topological arrangement of fibro- and hyaline cartilage may provide mechanical support for the chondroepiphysis. The osteological correlates identified here will inform systematic and functional analyses of archosaur hindlimb evolution and provide the anatomical foundation for biomechanical investigations of joint tissues. © 2014 Wiley Periodicals, Inc.

Morphology and ontogenesis of Psilotrichides hawaiiensis nov. gen., nov. spec. and molecular phylogeny of the Psilotrichidae (Ciliophora, Hypotrichia).

PubMed

Heber, Domingo; Stoeck, Thorsten; Foissner, Wilhelm

2014-01-01

The Psilotrichidae are a family of middle-sized hypotrichs with unique morphological and ontogenetic features (e.g. the oral primordium develops in a deep pouch) that, however, did not provide a definite phylogenetic signal. Thus, we studied the 18S rRNA gene of Urospinula succisa (Müller 1786) Esteban et al., 2001 as well as the morphology and ontogenesis of Psilotrichides hawaiiensis, a new genus and species from an ephemeral swamp on Oahu Island, Hawaii. The molecular data classify the psilotrichids into the oxytrichids but without clear branching position. A brief revision, using the structure of the oral apparatus, the location of the contractile vacuole, and three ontogenetic features, showed four distinct genera: Psilotricha Stein, 1859; Urospinula Corliss, 1960; Hemiholosticha Gelei, 1954; and Psilotrichides nov. gen., which differs from the confamilials mainly by the obliquely oriented buccal cavity and the shape of the undulating membranes as well as by a distinct ridge along the right buccal margin. The pyriform species, P. hawaiiensis, is about 65 × 45 μm in size and is easily recognized by the table tennis racket-shaped appearance due to the elongated last cirrus of the left marginal row. Refined diagnoses are provided for the family Psilotrichidae Bütschli, 1889 and the genera contained. © 2014 The Author(s) Journal of Eukaryotic Microbiology © 2014 International Society of Protistologists.

Phylogeography and alpha taxonomy of the common dolphin (Delphinus sp.).

PubMed

Natoli, A; Cañadas, A; Peddemors, V M; Aguilar, A; Vaquero, C; Fernández-Piqueras, P; Hoelzel, A R

2006-05-01

The resolution of taxonomic classifications for delphinid cetaceans has been problematic, especially for species in the genera Delphinus, Tursiops and Stenella. The frequent lack of correspondence between morphological and genetic differentiation in these species raises questions about the mechanisms responsible for their evolution. In this study we focus on the genus Delphinus, and use molecular markers to address questions about speciation and the evolution of population structure. Delphinus species have a worldwide distribution and show a high degree of morphological variation. Two distinct morphotypes, long-beaked and short-beaked, have been considered different species named D. capensis and D. delphis, respectively. However, genetic differentiation between these two forms has only been demonstrated in the Pacific. We analysed samples from eight different geographical regions, including two morphologically defined long-beaked form populations, and compared these with the eastern North Pacific populations. We found high differentiation among the populations described as long-beaked instead of the expected monophyly, suggesting that these populations may have evolved from independent events converging on the same morphotype. We observed low genetic differentiation among the short-beaked populations across a large geographical scale. We interpret these phylogeographical patterns in the context of life history and population structure in related species.

Identification of Lygus hesperus by DNA barcoding reveals insignificant levels of genetic structure among distant and habitat diverse populations.

PubMed

Zhou, Changqing; Kandemir, Irfan; Walsh, Douglas B; Zalom, Frank G; Lavine, Laura Corley

2012-01-01

The western tarnished plant bug Lygus hesperus is an economically important pest that belongs to a complex of morphologically similar species that makes identification problematic. The present study provides evidence for the use of DNA barcodes from populations of L. hesperus from the western United States of America for accurate identification. This study reports DNA barcodes for 134 individuals of the western tarnished plant bug from alfalfa and strawberry agricultural fields in the western United States of America. Sequence divergence estimates of <3% reveal that morphologically variable individuals presumed to be L. hesperus were accurately identified. Paired estimates of F(st) and subsequent estimates of gene flow show that geographically distinct populations of L. hesperus are genetically similar. Therefore, our results support and reinforce the relatively recent (<100 years) migration of the western tarnished plant bug into agricultural habitats across the western United States. This study reveals that despite wide host plant usage and phenotypically plastic morphological traits, the commonly recognized western tarnished plant bug belongs to a single species, Lygus hesperus. In addition, no significant genetic structure was found for the geographically diverse populations of western tarnished plant bug used in this study.

Two-Fold Anisotropy Governs Morphological Evolution and Stress Generation in Sodiated Black Phosphorus for Sodium Ion Batteries.

PubMed

Chen, Tianwu; Zhao, Peng; Guo, Xu; Zhang, Sulin

2017-04-12

Phosphorus represents a promising anode material for sodium ion batteries owing to its extremely high theoretical capacity. Recent in situ transmission electron microscopy studies evidenced anisotropic swelling in sodiated black phosphorus, which may find an origin from the two intrinsic anisotropic properties inherent to the layered structure of black phosphorus: sodium diffusional directionality and insertion strain anisotropy. To understand the morphological evolution and stress generation in sodiated black phosphorus, we develop a chemo-mechanical model by incorporating the intrinsic anisotropic properties into the large elasto-plastic deformation. Our modeling results reveal that the apparent morphological evolution in sodiated black phosphorus is critically controlled by the coupled effect of the two intrinsic anisotropic properties. In particular, sodium diffusional directionality generates sharp interphases along the [010] and [001] directions, which constrain anisotropic development of the insertion strain. The coupled effect renders distinctive stress-generation and fracture mechanisms when sodiation starts from different crystal facets. In addition to providing a powerful modeling framework for sodiation and lithiation of layered structures, our findings shed significant light on the sodiation-induced chemo-mechanical degradation of black phosphorus as a promising anode for the next-generation sodium ion batteries.

Crinipellis brasiliensis, a new species based on morphological and molecular data.

PubMed

de Arruda, Maricília C C; Sepulveda, German F; Miller, Robert N G; Ferreira, Marisa A S V; Santiago, Denise V R; Resende, Mário Lúcio V; Dianese, José Carmine; Felipe, Maria Sueli S

2005-01-01

Crinipellis perniciosa infects a diversity of hosts causing severe damage to T. cacao production in many Brazilian growing regions. We compared isolates of Crinipellis from different geographic origins and hosts in Brazil by structural analysis using light (LM) and scanning electronic microscopy (SEM), as well as RFLP and sequence data based on the nuclear rDNA ITS region. Statistical analyses of morphometric data of basidia and basidiospores revealed a distinct group of isolates of Crinipellis obtained from Heteropterys acutifolia when compared to representatives from Theobroma cacao, Solanum lycocarpum and Heteropterys nervosa. A similar distinction also was observed based on sequence data of the ITS region such that combined results allowed for the segregation of a new species within the genus Crinipellis.

Populations of subplate and interstitial neurons in fetal and adult human telencephalon.

PubMed

Judaš, Miloš; Sedmak, Goran; Pletikos, Mihovil; Jovanov-Milošević, Nataša

2010-10-01

In the adult human telencephalon, subcortical (gyral) white matter contains a special population of interstitial neurons considered to be surviving descendants of fetal subplate neurons [Kostovic & Rakic (1980) Cytology and the time of origin of interstitial neurons in the white matter in infant and adult human and monkey telencephalon. J Neurocytol9, 219]. We designate this population of cells as superficial (gyral) interstitial neurons and describe their morphology and distribution in the postnatal and adult human cerebrum. Human fetal subplate neurons cannot be regarded as interstitial, because the subplate zone is an essential part of the fetal cortex, the major site of synaptogenesis and the 'waiting' compartment for growing cortical afferents, and contains both projection neurons and interneurons with distinct input-output connectivity. However, although the subplate zone is a transient fetal structure, many subplate neurons survive postnatally as superficial (gyral) interstitial neurons. The fetal white matter is represented by the intermediate zone and well-defined deep periventricular tracts of growing axons, such as the corpus callosum, anterior commissure, internal and external capsule, and the fountainhead of the corona radiata. These tracts gradually occupy the territory of transient fetal subventricular and ventricular zones.The human fetal white matter also contains distinct populations of deep fetal interstitial neurons, which, by virtue of their location, morphology, molecular phenotypes and advanced level of dendritic maturation, remain distinct from subplate neurons and neurons in adjacent structures (e.g. basal ganglia, basal forebrain). We describe the morphological, histochemical (nicotinamide-adenine dinucleotide phosphate-diaphorase) and immunocytochemical (neuron-specific nuclear protein, microtubule-associated protein-2, calbindin, calretinin, neuropeptide Y) features of both deep fetal interstitial neurons and deep (periventricular) interstitial neurons in the postnatal and adult deep cerebral white matter (i.e. corpus callosum, anterior commissure, internal and external capsule and the corona radiata/centrum semiovale). Although these deep interstitial neurons are poorly developed or absent in the brains of rodents, they represent a prominent feature of the significantly enlarged white matter of human and non-human primate brains. © 2010 The Authors. Journal of Anatomy © 2010 Anatomical Society of Great Britain and Ireland.

Organizing groundwater regimes and response thresholds by soils: A framework for understanding runoff generation in a headwater catchment

Treesearch

John P. Gannon; Scott W. Bailey; Kevin J. McGuire

2014-01-01

A network of shallow groundwater wells in a headwater catchment at the Hubbard Brook Experimental Forest in New Hampshire, U.S. was used to investigate the hydrologic behavior of five distinct soil morphological units. The soil morphological units were hypothesized to be indicative of distinct water table regimes. Water table fluctuations in the wells were...

Herpesvirus infections in psittacine birds in Japan.

PubMed

Tsai, S S; Park, J H; Hirai, K; Itakura, C

1993-03-01

Herpesvirus infection was diagnosed histologically and electron microscopically in 21 out of 241 pet birds examined. The infected birds included 14 parakeets (Psittacula krameri manillensis) with respiratory infection and three parrots (Ama-zona aestiva aestiva), two cockatiels (Nymphicus hollandicus) and two rosellas (Platycercus emimius) with Pacheco's disease. The consistent lesions of respiratory herpesvirus infection were the formation of syncytial cells associated with the presence of intranuclear inclusion bodies, mainly in the lung and air sac. There was lack of an apparent cellular reaction in situ. The agent induced tubular structures containing a clear core in the nuclei of the affected cells. The present study indicated that it was a distinct entity from infectious laryngotracheitis based on tissue tropism, host reaction and morphology of the tubular structures. The striking lesions of Pacheco's disease consisted of syncytial cell formation with intranuclear inclusion bodies in various organs, especially the liver, parathyroid, ovary, bone marrow and intestine. This agent showed similar morphology to that of the respiratory herpesvirus infection, but was larger in size and had no tubular structure formation in the nuclei of affected cells.

Molecular Diversity of Cyanobacteria Inhabiting Coniform Structures and Surrounding Mat in a Yellowstone Hot Spring

NASA Astrophysics Data System (ADS)

Lau, Evan; Nash, Cody Z.; Vogler, Detlev R.; Cullings, K. W.

2005-02-01

Lithified coniform structures are common within cyanobacterial mats in Yellowstone National Park hot springs. It is unknown whether these structures and the mats from which they develop are inhabited by the same cyanobacterial populations. Denaturing gradient gel electrophoresis and sequencing and phylogenetic analysis of 16S rDNA was used to determine whether (1) three different morphological types of lithified coniform structures are inhabited by different cyanobacterial species, (2) these species are partitioned along a vertical gradient of these structures, and (3) lithified and non-lithified sections of mat are inhabited by different cyanobacterial species. Our results, based on multiple samplings, indicate that the cyanobacterial community compositions in the three lithified morphological types were identical and lacked any vertical differentiation. However, lithified and non-lithified portions of the same mat were inhabited by distinct and different populations of cyanobacteria. Cyanobacteria inhabiting lithified structures included at least one undefined Oscillatorialean taxon, which may represent the dominant cyanobacteria genus in lithified coniform stromatolites, Phormidium, three Synechococcus-like species, and two unknown cyanobacterial taxa. In contrast, the surrounding mats contained four closely related Synechococcus-like species. Our results indicate that the distribution of lithified coniform stromatolites may be dependent on the presence of one or more microorganisms, which are phylogenetically different from those inhabiting surrounding non-lithified mats.

Morphological changes in human melanoma cells following irradiation with thermal neutrons.

PubMed

Barkla, D H; Allen, B J; Brown, J K; Mountford, M; Mishima, Y; Ichihashi, M

1989-01-01

Morphological changes in two human melanoma cell lines, MM96 and MM418, following irradiation with thermal neutrons, were studied using light and electron microscopy. The results show that the response of human malignant melanoma cells to neutron irradiation is both cell line dependent and dose dependent, and that in any given cell line, some cells are more resistant to irradiation than others, thus demonstrating heterogeneity in respect to radiosensitivity. Cells repopulating MM96 flasks after irradiation were morphologically similar to the cells of origin whereas in MM418 flasks cells differentiated into five morphologically distinct subgroups and showed increased melanization. The results also show that radiation causes distinctive morphological patterns of damage although ultrastructural changes unique to the high LET particles released from boron 10 neutron capture are yet to be identified.

The declarative/procedural model of lexicon and grammar.

PubMed

Ullman, M T

2001-01-01

Our use of language depends upon two capacities: a mental lexicon of memorized words and a mental grammar of rules that underlie the sequential and hierarchical composition of lexical forms into predictably structured larger words, phrases, and sentences. The declarative/procedural model posits that the lexicon/grammar distinction in language is tied to the distinction between two well-studied brain memory systems. On this view, the memorization and use of at least simple words (those with noncompositional, that is, arbitrary form-meaning pairings) depends upon an associative memory of distributed representations that is subserved by temporal-lobe circuits previously implicated in the learning and use of fact and event knowledge. This "declarative memory" system appears to be specialized for learning arbitrarily related information (i.e., for associative binding). In contrast, the acquisition and use of grammatical rules that underlie symbol manipulation is subserved by frontal/basal-ganglia circuits previously implicated in the implicit (nonconscious) learning and expression of motor and cognitive "skills" and "habits" (e.g., from simple motor acts to skilled game playing). This "procedural" system may be specialized for computing sequences. This novel view of lexicon and grammar offers an alternative to the two main competing theoretical frameworks. It shares the perspective of traditional dual-mechanism theories in positing that the mental lexicon and a symbol-manipulating mental grammar are subserved by distinct computational components that may be linked to distinct brain structures. However, it diverges from these theories where they assume components dedicated to each of the two language capacities (that is, domain-specific) and in their common assumption that lexical memory is a rote list of items. Conversely, while it shares with single-mechanism theories the perspective that the two capacities are subserved by domain-independent computational mechanisms, it diverges from them where they link both capacities to a single associative memory system with broad anatomic distribution. The declarative/procedural model, but neither traditional dual- nor single-mechanism models, predicts double dissociations between lexicon and grammar, with associations among associative memory properties, memorized words and facts, and temporal-lobe structures, and among symbol-manipulation properties, grammatical rule products, motor skills, and frontal/basal-ganglia structures. In order to contrast lexicon and grammar while holding other factors constant, we have focused our investigations of the declarative/procedural model on morphologically complex word forms. Morphological transformations that are (largely) unproductive (e.g., in go-went, solemn-solemnity) are hypothesized to depend upon declarative memory. These have been contrasted with morphological transformations that are fully productive (e.g., in walk-walked, happy-happiness), whose computation is posited to be solely dependent upon grammatical rules subserved by the procedural system. Here evidence is presented from studies that use a range of psycholinguistic and neurolinguistic approaches with children and adults. It is argued that converging evidence from these studies supports the declarative/procedural model of lexicon and grammar.

Bimetallic Platinum-Rhodium Alloy Nanodendrites as Highly Active Electrocatalyst for the Ethanol Oxidation Reaction.

PubMed

Bai, Juan; Xiao, Xue; Xue, Yuan-Yuan; Jiang, Jia-Xing; Zeng, Jing-Hui; Li, Xi-Fei; Chen, Yu

2018-06-13

Rationally designing and manipulating composition and morphology of precious metal-based bimetallic nanostructures can markedly enhance their electrocatalytic performance, including selectivity, activity, and durability. We herein report the synthesis of bimetallic PtRh alloy nanodendrites (ANDs) with tunable composition by a facile complex-reduction synthetic method under hydrothermal conditions. The structural/morphologic features, formation mechanism, and electrocatalytic performance of PtRh ANDs are investigated thoroughly by various physical characterization and electrochemical methods. The preformed Rh crystal nuclei effectively catalyze the reduction of Pt 2+ precursor, resulting in PtRh alloy generation due to the catalytic growth and atoms interdiffusion process. The Pt atoms deposition distinctly interferes in Rh atoms deposition on Rh crystal nuclei, resulting in dendritic morphology of PtRh ANDs. For the ethanol oxidation reaction (EOR), PtRh ANDs display the chemical composition and solution pH co-dependent electrocatalytic activity. Because of the alloy effect and particular morphologic feature, Pt 1 Rh 1 ANDs with optimized composition exhibit better reactivity and stability for the EOR than commercial Pt nanocrystals electrocatalyst.

Overexpression of the lamina proteins Lamin and Kugelkern induces specific ultrastructural alterations in the morphology of the nuclear envelope of intestinal stem cells and enterocytes.

PubMed

Petrovsky, Roman; Krohne, Georg; Großhans, Jörg

2018-03-01

The nuclear envelope has a stereotypic morphology consisting of a flat double layer of the inner and outer nuclear membrane, with interspersed nuclear pores. Underlying and tightly linked to the inner nuclear membrane is the nuclear lamina, a proteinous layer of intermediate filament proteins and associated proteins. Physiological, experimental or pathological alterations in the constitution of the lamina lead to changes in nuclear morphology, such as blebs and lobulations. It has so far remained unclear whether the morphological changes depend on the differentiation state and the specific lamina protein. Here we analysed the ultrastructural morphology of the nuclear envelope in intestinal stem cells and differentiated enterocytes in adult Drosophila flies, in which the proteins Lam, Kugelkern or a farnesylated variant of LamC were overexpressed. Surprisingly, we detected distinct morphological features specific for the respective protein. Lam induced envelopes with multiple layers of membrane and lamina, surrounding the whole nucleus whereas farnesylated LamC induced the formation of a thick fibrillary lamina. In contrast, Kugelkern induced single-layered and double-layered intranuclear membrane structures, which are likely be derived from infoldings of the inner nuclear membrane or of the double layer of the envelope. Copyright © 2018 Elsevier GmbH. All rights reserved.

Cell–material interactions on biphasic polyurethane matrix

PubMed Central

Dicesare, Patrick; Fox, Wade M.; Hill, Michael J.; Krishnan, G. Rajesh; Yang, Shuying; Sarkar, Debanjan

2013-01-01

Cell–matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell–matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. PMID:23255285

The crustal structure of the Enderby Basin, East Antarctica

NASA Astrophysics Data System (ADS)

Davis, Joshua K.; Lawver, Lawrence A.; Norton, Ian O.; Dalziel, Ian W. D.; Gahagan, Lisa M.

2018-05-01

The passive margin and ocean crust of the Enderby Basin, East Antarctica preserves a record of the breakup of East Gondwana. Using a suite of public domain geophysical data, we have examined and described the crustal morphology of the basin. Based on our geophysical observations, we divide the Enderby Basin into three distinct morphologic domains. The Eastern Domain demonstrates the most volcanic morphology of the basin, with abundant seaward dipping reflector packages and anomalously thick oceanic crust. These features suggest an early influence by the Kerguelen Hotspot on continental breakup within the domain. The Central Domain is characterized by two regions of oceanic crust of varying morphology segregated by a high amplitude magnetic anomaly. Geophysical observations suggest that the basement directly inboard of this magnetic anomaly is composed of thin, rugged, and poorly structured, proto-oceanic crust, similar in morphology to oceanic crust formed at ultraslow/slow mid-ocean ridged. Outboard of this anomaly, oceanic crust appears to be well-structured and of normal thickness. We offer three, non-exclusive, explanations for the observed change in ocean crustal structure: (1) melt production was initially low at the time of continental breakup, and the progressive decompression of the mantle led to a gradual increase in melt production and ocean crust thickness, (2) melt production was initially low to due lower extension rates and that melt production increased following a change in spreading rate, (3) a change in spreading ridge geometry led to more effective seafloor spreading rate and concurrent increase in melt production. The Western Domain of the Enderby Basin is characterized by abundant fracture zones and anomalously thin oceanic crust. We believe these features arose as a geometric consequence of the originally oblique orientation of continental rifting relative to the extension direction within the domain. Together these observations suggest that the breakup of East Gondwana was highly variable, with notable along-strike differences in crustal deformation and seafloor spreading processes.

Holocene freshwater carbonate structures in the hyper-arid Gebel Uweinat region of the Sahara Desert (Southwestern Egypt)

NASA Astrophysics Data System (ADS)

Marinova, Margarita M.; Meckler, A. Nele; McKay, Christopher P.

2014-01-01

The eastern part of the Sahara is at present the driest region of the desert. Yet the extensive animal rock art in the area, presumed to depict real activities in the lives of the painters, suggests that environmental conditions were significantly different when the rock art was produced. Here we report on exploration of the area, which led to the discovery of morphologically-distinct carbonate structures that line the walls of two valleys in Gebel Uweinat, and were likely formed in standing water. The carbonate structures comprise what appear to be shoreline carbonate formations, and date back to 8100 and 9400 years BP. The chemical and morphological similarity of these formations to carbonate structures from modern lakes suggests that these lakes contained fresh, standing water suitable for human and animal use. However, the significant quartz content suggests that windblown sand was pervasive, and thus the vegetation cover may have been sparse. This discovery supports the possibility of grasslands in the area, which may have been able to support human habitation, and adds to the evidence for a wetter climate in the area in the early Holocene.

Effects of transition-metal ions on the morphology and electrochemical properties of δ-MnO2 for supercapacitors

NASA Astrophysics Data System (ADS)

Wang, Jia-Wei; Chen, Ya; Chen, Bai-Zhen

2014-11-01

δ-MnO2 materials doped with transition-metal cations (Zn, Co, and Ag) were successfully synthesized using a hydrothermal technique. The structures and morphologies of the obtained oxides were analyzed using X-ray diffraction, scanning electron microscopy and Brunauer-Emmett-Teller measurements. Additionally, the electrochemical properties were evaluated through cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic cycling measurements. The results indicate that the pure and doped samples crystallize in the δ form with a layered structure and that the Mn/Zn, Mn/Co and Mn/Ag molar ratios are all approximately 1:0.09. Both the Zn-doped and pure MnO2 materials exhibit a petal-like morphology; however, the former has a higher specific surface area of up to 98.97m2 g-1. Furthermore, the Zn-doped MnO2 exhibits a near-rectangular cyclic voltammetry (CV) curve with broad quasi-reversible redox peaks and a specific capacitance of 182.9 F g-1 at a CV scan rate of 2 mV s-1. The Co-doped material exhibits a distinct spiny-fiber morphology, and the electrochemical performance of this material is significantly worse than that of pure MnO2. The average attenuation rate of the Ag-doped material is only 0.028% after 1000 cycles, which is lower than that of pure MnO2.

Morphological diagnostics of star formation in molecular clouds

NASA Astrophysics Data System (ADS)

Beaumont, Christopher Norris

Molecular clouds are the birth sites of all star formation in the present-day universe. They represent the initial conditions of star formation, and are the primary medium by which stars transfer energy and momentum back to parsec scales. Yet, the physical evolution of molecular clouds remains poorly understood. This is not due to a lack of observational data, nor is it due to an inability to simulate the conditions inside molecular clouds. Instead, the physics and structure of the interstellar medium are sufficiently complex that interpreting molecular cloud data is very difficult. This dissertation mitigates this problem, by developing more sophisticated ways to interpret morphological information in molecular cloud observations and simulations. In particular, I have focused on leveraging machine learning techniques to identify physically meaningful substructures in the interstellar medium, as well as techniques to inter-compare molecular cloud simulations to observations. These contributions make it easier to understand the interplay between molecular clouds and star formation. Specific contributions include: new insight about the sheet-like geometry of molecular clouds based on observations of stellar bubbles; a new algorithm to disambiguate overlapping yet morphologically distinct cloud structures; a new perspective on the relationship between molecular cloud column density distributions and the sizes of cloud substructures; a quantitative analysis of how projection effects affect measurements of cloud properties; and an automatically generated, statistically-calibrated catalog of bubbles identified from their infrared morphologies.

Spatial discrimination of persistent EUV oscillations in a hot waning light bridge

NASA Astrophysics Data System (ADS)

Walsh, D.; Yuan, R. W.

2016-10-01

A light bridge is usually formed as a lower atmospheric structure in nascent or decaying sunspots; it divides the umbra into separate regions. Convection, which is normally suppressed by a sunspot's strong magnetic field, is partially restored and upflows are usually observed at the spine of a bridge with downflows (or return flows) at the two flanks. This study outlines observations a light bridge unusually sustained at coronal temperatures. Viewed in AR11520 on 12th July 2012 by the High Resolution Coronal Imager (HiC) and AIA/SDO, the EUV emission intensity exhibits two persistent oscillations. The approximate 5-minute oscillations are distributed along the spine of the light bridge whereas sub-minute oscillations are distinctively co-spatial along each bridge flank (though there is a distinct time-lag between them). This indicates strongly that (i) the oscillatory driver at the flanks is connected with the collective interactions between magnetic fields of the bridge and the sunspot itself and (ii) the internal magnetic structure of the bridge is twisted. The presentation will outline the distinct oscillatory maps generated and provide insight into determining the magnetic morphology until the bridge wans several hours later.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Missert, Nancy; Kotula, Paul G.; Rye, Michael

We used a focused ion beam to obtain cross-sectional specimens from both magnetic multilayer and Nb/Al-AlOx/Nb Josephson junction devices for characterization by scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDX). An automated multivariate statistical analysis of the EDX spectral images produced chemically unique component images of individual layers within the multilayer structures. STEM imaging elucidated distinct variations in film morphology, interface quality, and/or etch artifacts that could be correlated to magnetic and/or electrical properties measured on the same devices.

Lunar crater volumes - Interpretation by models of impact cratering and upper crustal structure

NASA Technical Reports Server (NTRS)

Croft, S. K.

1978-01-01

Lunar crater volumes can be divided by size into two general classes with distinctly different functional dependence on diameter. Craters smaller than approximately 12 km in diameter are morphologically simple and increase in volume as the cube of the diameter, while craters larger than about 20 km are complex and increase in volume at a significantly lower rate implying shallowing. Ejecta and interior volumes are not identical and their ratio, Schroeters Ratio (SR), increases from about 0.5 for simple craters to about 1.5 for complex craters. The excess of ejecta volume causing the increase, can be accounted for by a discontinuity in lunar crust porosity at 1.5-2 km depth. The diameter range of significant increase in SR corresponds with the diameter range of transition from simple to complex crater morphology. This observation, combined with theoretical rebound calculation, indicates control of the transition diameter by the porosity structure of the upper crust.

Ridges and scarps in the equatorial belt of Mars

USGS Publications Warehouse

Lucchitta, B.K.; Klockenbrink, J.L.

1981-01-01

The morphology and distribution of ridges and scarps on Mars in the ?? 30?? latitude belt were investigated. Two distinct types of ridges were recognized. The first is long and linear, resembling mare ridges on the Moon; it occurs mostly in plains areas. The other is composed of short, anastomosing segments and occurs mostly in ancient cratered terrain and intervening plateaus. Where ridges are eroded, landscape configurations suggest that they are located along regional structures. The age of ridges is uncertain, but some are as young as the latest documented volcanic activity on Mars. The origins of ridges are probably diverse-they may result from wrinkling due to compression or from buckling due to settling over subsurface structures. The similar morphologic expressions of ridge types of various origins may be related to a similar deformation mechanism caused by two main factors: (1) most ridges are developed in thick layers of competent material and (2) ridges formed under stresses near a free surface. ?? 1981 D. Reidel Publishing Co.

Morphology and Proton Transport in Sulfonated Block Copolymer and Mesoporous Polymer Electrolyte Membranes

NASA Astrophysics Data System (ADS)

Chen, Chelsea; Wong, David; Beers, Keith; Balsara, Nitash

2013-03-01

In an effort to understand the fundamentals of proton transport in polymer electrolyte membranes (PEMs), we have developed a series of poly(styrene-b-ethylene-b-styrene) (SES) membranes. The SES membranes were subsequently sulfonated to yield proton conducting S-SES membranes. We examine the effects of sulfonation level, temperature and thermal history on the morphology of S-SES membranes in both dry and hydrated states. The effects of these parameters on water uptake and proton transport characteristics of the membranes are also examined. Furthermore, building upon the strategy we deployed in sulfonating the SES membranes, we fabricated mesoporous S-SES membranes, with pores lined up with the proton conducting channels. These membranes have three distinct phases: structural block, proton-conducting block, and void. We examine the effects of pore size, domain structure and sulfonation level on water uptake and proton conductivity of the mesoporous PEMs at different temperatures. This work is funded by Department of Energy.

Functional morphology of parasitic isopods: understanding morphological adaptations of attachment and feeding structures in Nerocila as a pre-requisite for reconstructing the evolution of Cymothoidae.

PubMed

Nagler, Christina; Haug, Joachim T

2016-01-01

Parasites significantly influence food webs and ecosystems and occur all over the world in almost every animal group. Within crustaceans there are numerous examples of ectoparasites; for example, representatives of the isopod group Cymothoidae. These obligatory parasitic isopods are relatively poorly studied regarding their functional morphology. Here we present new details of the morphological adaptations to parasitism of the cymothoiid ingroup Nerocila with up-to-date imaging methods (macro photography, stereo imaging, fluorescence photography, micro CT, and histology). Central aspects of the study were (1) the morphology of the mouthparts and (2) the attachment on the host, hence the morphology of the thoracopods. The mouthparts (labrum, mandibles, paragnaths, maxillulae, maxillae, maxillipeds) form a distinct mouth cone and are most likely used for true sucking. The mouthparts are tightly "folded" around each other and provide functional rails for the only two moving mouthparts, mandible and maxillula. Both are not moving in an ancestral-type median-lateral movement, but are strongly tilted to move more in a proximal-distal axis. New details concerning the attachment demonstrate that the angular arrangement of the thoracopods is differentiated to impede removal by the host. The increased understanding of morphological adaptation to parasitism of modern forms will be useful in identifying disarticulated (not attached to the host) fossil parasites.

Functional morphology of parasitic isopods: understanding morphological adaptations of attachment and feeding structures in Nerocila as a pre-requisite for reconstructing the evolution of Cymothoidae

PubMed Central

Haug, Joachim T.

2016-01-01

Parasites significantly influence food webs and ecosystems and occur all over the world in almost every animal group. Within crustaceans there are numerous examples of ectoparasites; for example, representatives of the isopod group Cymothoidae. These obligatory parasitic isopods are relatively poorly studied regarding their functional morphology. Here we present new details of the morphological adaptations to parasitism of the cymothoiid ingroup Nerocila with up-to-date imaging methods (macro photography, stereo imaging, fluorescence photography, micro CT, and histology). Central aspects of the study were (1) the morphology of the mouthparts and (2) the attachment on the host, hence the morphology of the thoracopods. The mouthparts (labrum, mandibles, paragnaths, maxillulae, maxillae, maxillipeds) form a distinct mouth cone and are most likely used for true sucking. The mouthparts are tightly “folded” around each other and provide functional rails for the only two moving mouthparts, mandible and maxillula. Both are not moving in an ancestral-type median-lateral movement, but are strongly tilted to move more in a proximal-distal axis. New details concerning the attachment demonstrate that the angular arrangement of the thoracopods is differentiated to impede removal by the host. The increased understanding of morphological adaptation to parasitism of modern forms will be useful in identifying disarticulated (not attached to the host) fossil parasites. PMID:27441121

Alterations in zebrafish development induced by simvastatin: Comprehensive morphological and physiological study, focusing on muscle

PubMed Central

Campos, Laise M; Rios, Eduardo A; Guapyassu, Livia; Midlej, Victor; Atella, Georgia C; Herculano-Houzel, Suzana; Benchimol, Marlene; Mermelstein, Claudia

2016-01-01

The cholesterol synthesis inhibitor simvastatin, which is used to treat cardiovascular diseases, has severe collateral effects. We decided to comprehensively study the effects of simvastatin in zebrafish development and in myogenesis, because zebrafish has been used as a model to human diseases, due to its handling easiness, the optical clarity of its embryos, and the availability of physiological and structural methodologies. Furthermore, muscle is an important target of the drug. We used several simvastatin concentrations at different zebrafish developmental stages and studied survival rate, morphology, and physiology of the embryos. Our results show that high levels of simvastatin induce structural damage whereas low doses induce minor structural changes, impaired movements, and reduced heart beating. Morphological alterations include changes in embryo and somite size and septa shape. Physiological changes include movement reduction and slower heartbeat. These effects could be reversed by the addition of exogenous cholesterol. Moreover, we quantified the total cell number during zebrafish development and demonstrated a large reduction in cell number after statin treatment. Since we could classify the alterations induced by simvastatin in three distinct phenotypes, we speculate that simvastatin acts through more than one mechanism and could affect both cell replication and/or cell death and muscle function. Our data can contribute to the understanding of the molecular and cellular basis of the mechanisms of action of simvastatin. PMID:27444151

Alterations in zebrafish development induced by simvastatin: Comprehensive morphological and physiological study, focusing on muscle.

PubMed

Campos, Laise M; Rios, Eduardo A; Guapyassu, Livia; Midlej, Victor; Atella, Georgia C; Herculano-Houzel, Suzana; Benchimol, Marlene; Mermelstein, Claudia; Costa, Manoel L

2016-11-01

The cholesterol synthesis inhibitor simvastatin, which is used to treat cardiovascular diseases, has severe collateral effects. We decided to comprehensively study the effects of simvastatin in zebrafish development and in myogenesis, because zebrafish has been used as a model to human diseases, due to its handling easiness, the optical clarity of its embryos, and the availability of physiological and structural methodologies. Furthermore, muscle is an important target of the drug. We used several simvastatin concentrations at different zebrafish developmental stages and studied survival rate, morphology, and physiology of the embryos. Our results show that high levels of simvastatin induce structural damage whereas low doses induce minor structural changes, impaired movements, and reduced heart beating. Morphological alterations include changes in embryo and somite size and septa shape. Physiological changes include movement reduction and slower heartbeat. These effects could be reversed by the addition of exogenous cholesterol. Moreover, we quantified the total cell number during zebrafish development and demonstrated a large reduction in cell number after statin treatment. Since we could classify the alterations induced by simvastatin in three distinct phenotypes, we speculate that simvastatin acts through more than one mechanism and could affect both cell replication and/or cell death and muscle function. Our data can contribute to the understanding of the molecular and cellular basis of the mechanisms of action of simvastatin. © 2016 by the Society for Experimental Biology and Medicine.

Quantitative and Qualitative Differences in Morphological Traits Revealed between Diploid Fragaria Species

PubMed Central

SARGENT, DANIEL J.; GEIBEL, M.; HAWKINS, J. A.; WILKINSON, M. J.; BATTEY, N. H.; SIMPSON, D. W.

2004-01-01

• Background and Aims The aims of this investigation were to highlight the qualitative and quantitative diversity apparent between nine diploid Fragaria species and produce interspecific populations segregating for a large number of morphological characters suitable for quantitative trait loci analysis. • Methods A qualitative comparison of eight described diploid Fragaria species was performed and measurements were taken of 23 morphological traits from 19 accessions including eight described species and one previously undescribed species. A principal components analysis was performed on 14 mathematically unrelated traits from these accessions, which partitioned the species accessions into distinct morphological groups. Interspecific crosses were performed with accessions of species that displayed significant quantitative divergence and, from these, populations that should segregate for a range of quantitative traits were raised. • Key Results Significant differences between species were observed for all 23 morphological traits quantified and three distinct groups of species accessions were observed after the principal components analysis. Interspecific crosses were performed between these groups, and F2 and backcross populations were raised that should segregate for a range of morphological characters. In addition, the study highlighted a number of distinctive morphological characters in many of the species studied. • Conclusions Diploid Fragaria species are morphologically diverse, yet remain highly interfertile, making the group an ideal model for the study of the genetic basis of phenotypic differences between species through map-based investigation using quantitative trait loci. The segregating interspecific populations raised will be ideal for such investigations and could also provide insights into the nature and extent of genome evolution within this group. PMID:15469944

Comparative brain morphology of Neotropical parrots (Aves, Psittaciformes) inferred from virtual 3D endocasts.

PubMed

Carril, Julieta; Tambussi, Claudia Patricia; Degrange, Federico Javier; Benitez Saldivar, María Juliana; Picasso, Mariana Beatriz Julieta

2016-08-01

Psittaciformes are a very diverse group of non-passerine birds, with advanced cognitive abilities and highly developed locomotor and feeding behaviours. Using computed tomography and three-dimensional (3D) visualization software, the endocasts of 14 extant Neotropical parrots were reconstructed, with the aim of analysing, comparing and exploring the morphology of the brain within the clade. A 3D geomorphometric analysis was performed, and the encephalization quotient (EQ) was calculated. Brain morphology character states were traced onto a Psittaciformes tree in order to facilitate interpretation of morphological traits in a phylogenetic context. Our results indicate that: (i) there are two conspicuously distinct brain morphologies, one considered walnut type (quadrangular and wider than long) and the other rounded (narrower and rostrally tapered); (ii) Psittaciformes possess a noticeable notch between hemisphaeria that divides the bulbus olfactorius; (iii) the plesiomorphic and most frequently observed characteristics of Neotropical parrots are a rostrally tapered telencephalon in dorsal view, distinctly enlarged dorsal expansion of the eminentia sagittalis and conspicuous fissura mediana; (iv) there is a positive correlation between body mass and brain volume; (v) psittacids are characterized by high EQ values that suggest high brain volumes in relation to their body masses; and (vi) the endocranial morphology of the Psittaciformes as a whole is distinctive relative to other birds. This new knowledge of brain morphology offers much potential for further insight in paleoneurological, phylogenetic and evolutionary studies. © 2015 Anatomical Society.

Comparing selected morphological models of hydrated Nafion using large scale molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Knox, Craig K.

Experimental elucidation of the nanoscale structure of hydrated Nafion, the most popular polymer electrolyte or proton exchange membrane (PEM) to date, and its influence on macroscopic proton conductance is particularly challenging. While it is generally agreed that hydrated Nafion is organized into distinct hydrophilic domains or clusters within a hydrophobic matrix, the geometry and length scale of these domains continues to be debated. For example, at least half a dozen different domain shapes, ranging from spheres to cylinders, have been proposed based on experimental SAXS and SANS studies. Since the characteristic length scale of these domains is believed to be ˜2 to 5 nm, very large molecular dynamics (MD) simulations are needed to accurately probe the structure and morphology of these domains, especially their connectivity and percolation phenomena at varying water content. Using classical, all-atom MD with explicit hydronium ions, simulations have been performed to study the first-ever hydrated Nafion systems that are large enough (~2 million atoms in a ˜30 nm cell) to directly observe several hydrophilic domains at the molecular level. These systems consisted of six of the most significant and relevant morphological models of Nafion to-date: (1) the cluster-channel model of Gierke, (2) the parallel cylinder model of Schmidt-Rohr, (3) the local-order model of Dreyfus, (4) the lamellar model of Litt, (5) the rod network model of Kreuer, and (6) a 'random' model, commonly used in previous simulations, that does not directly assume any particular geometry, distribution, or morphology. These simulations revealed fast intercluster bridge formation and network percolation in all of the models. Sulfonates were found inside these bridges and played a significant role in percolation. Sulfonates also strongly aggregated around and inside clusters. Cluster surfaces were analyzed to study the hydrophilic-hydrophobic interface. Interfacial area and cluster volume significantly increased during the simulations, suggesting the need for morphological model refinement and improvement. Radial distribution functions and structure factors were calculated. All nonrandom models exhibited the characteristic experimental scattering peak, underscoring the insensitivity of this measurement to hydrophilic domain structure and highlighting the need for future work to clearly distinguish morphological models of Nafion.

Intraspecific Genetic Admixture and the Morphological Diversification of an Estuarine Fish Population Complex

PubMed Central

Legault, Michel

2015-01-01

The North-east American Rainbow smelt (Osmerus mordax) is composed of two glacial races first identified through the spatial distribution of two distinct mtDNA lineages. Contemporary breeding populations of smelt in the St. Lawrence estuary comprise contrasting mixtures of both lineages, suggesting that the two races came into secondary contact in this estuary. The overall objective of this study was to assess the role of intraspecific genetic admixture in the morphological diversification of the estuarine rainbow smelt population complex. The morphology of mixed-ancestry populations varied as a function of the relative contribution of the two races to estuarine populations, supporting the hypothesis of genetic admixture. Populations comprising both ancestral mtDNA races did not exhibit intermediate morphologies relative to pure populations but rather exhibited many traits that exceeded the parental trait values, consistent with the hypothesis of transgressive segregation. Evidence for genetic admixture at the level of the nuclear gene pool, however, provided only partial support for this hypothesis. Variation at nuclear AFLP markers revealed clear evidence of the two corresponding mtDNA glacial races. The admixture of the two races at the nuclear level is only pronounced in mixed-ancestry populations dominated by one of the mtDNA lineages, the same populations showing the greatest degree of morphological diversification and population structure. In contrast, mixed-ancestry populations dominated by the alternate mtDNA lineage showed little evidence of introgression of the nuclear genome, little morphological diversification and little contemporary population genetic structure. These results only partially support the hypothesis of transgressive segregation and may be the result of the differential effects of natural selection acting on admixed genomes from different sources. PMID:25856193

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kortright, Jeffrey Barrett; Sun, Jing; Spencer, Ryan K.

The evolution of molecular morphology in bulk samples of comb diblock copolymer pNdc 12-b-pNte 21 across the lamellar order-disorder transition (ODT) is studied using resonant x-ray scattering at the oxygen K edge, with the goal of determining whether the molecules remain extended or collapse above the ODT. The distinct spectral resonances of carbonyl oxygen on the backbone and ether oxygen in the pNte side chains combine with their different site symmetry within the molecule to yield strong differences in bulk structural sensitivity at all temperatures. Comparison with simple models for the disordered phase clearly reveals that disordering at the ODTmore » corresponds to loss of positional order of molecules with extended backbones that retain orientational order, rather than backbone collapse into a locally isotropic disordered phase. This conclusion is facilitated directly by the distinct structural sensitivity at the two resonances. Lastly, we discuss the roles of depolarized scattering in enhancing this sensitivity, and background fluorescence in limiting dynamic range, in oxygen resonant scattering.« less

Three Types of Cortical L5 Neurons that Differ in Brain-Wide Connectivity and Function

PubMed Central

Kim, Euiseok J.; Juavinett, Ashley L.; Kyubwa, Espoir M.; Jacobs, Matthew W.; Callaway, Edward M.

2015-01-01

SUMMARY Cortical layer 5 (L5) pyramidal neurons integrate inputs from many sources and distribute outputs to cortical and subcortical structures. Previous studies demonstrate two L5 pyramid types: cortico-cortical (CC) and cortico-subcortical (CS). We characterize connectivity and function of these cell types in mouse primary visual cortex and reveal a new subtype. Unlike previously described L5 CC and CS neurons, this new subtype does not project to striatum [cortico-cortical, non-striatal (CC-NS)] and has distinct morphology, physiology and visual responses. Monosynaptic rabies tracing reveals that CC neurons preferentially receive input from higher visual areas, while CS neurons receive more input from structures implicated in top-down modulation of brain states. CS neurons are also more direction-selective and prefer faster stimuli than CC neurons. These differences suggest distinct roles as specialized output channels, with CS neurons integrating information and generating responses more relevant to movement control and CC neurons being more important in visual perception. PMID:26671462

Three Types of Cortical Layer 5 Neurons That Differ in Brain-wide Connectivity and Function.

PubMed

Kim, Euiseok J; Juavinett, Ashley L; Kyubwa, Espoir M; Jacobs, Matthew W; Callaway, Edward M

2015-12-16

Cortical layer 5 (L5) pyramidal neurons integrate inputs from many sources and distribute outputs to cortical and subcortical structures. Previous studies demonstrate two L5 pyramid types: cortico-cortical (CC) and cortico-subcortical (CS). We characterize connectivity and function of these cell types in mouse primary visual cortex and reveal a new subtype. Unlike previously described L5 CC and CS neurons, this new subtype does not project to striatum [cortico-cortical, non-striatal (CC-NS)] and has distinct morphology, physiology, and visual responses. Monosynaptic rabies tracing reveals that CC neurons preferentially receive input from higher visual areas, while CS neurons receive more input from structures implicated in top-down modulation of brain states. CS neurons are also more direction-selective and prefer faster stimuli than CC neurons. These differences suggest distinct roles as specialized output channels, with CS neurons integrating information and generating responses more relevant to movement control and CC neurons being more important in visual perception. Copyright © 2015 Elsevier Inc. All rights reserved.

The multifunctional nuclear pore complex: a platform for controlling gene expression

PubMed Central

Ptak, Christopher; Aitchison, John D.; Wozniak, Richard W.

2014-01-01

In addition to their established roles in nucleocytoplasmic transport, the intimate association of nuclear pore complexes (NPCs) with chromatin has long led to speculation that these structures influence peripheral chromatin structure and regulate gene expression. These ideas have their roots in morphological observations, however recent years have seen the identification of physical interactions between NPCs, chromatin, and the transcriptional machinery. Key insights into the molecular functions of specific NPC proteins have uncovered roles for these proteins in transcriptional activation and elongation, mRNA processing, as well as chromatin structure and localization. Here, we review recent studies that provide further molecular detail on the role of specific NPC components as distinct platforms for these chromatin dependent processes. PMID:24657998

The neural correlates of apathy in schizophrenia: An exploratory investigation.

PubMed

Caravaggio, Fernando; Fervaha, Gagan; Menon, Mahesh; Remington, Gary; Graff-Guerrero, Ariel; Gerretsen, Philip

2017-10-25

Motivational deficits represent a core negative symptom in patients with schizophrenia. Previous morphology studies have demonstrated that apathy in patients with schizophrenia is associated with reduced frontal grey matter (GM). We attempted to replicate this previous finding, and explored whether it was distinct from potential associations with a distinct subdomain of negative symptoms, namely Affective Flattening, and GM. Twenty medicated patients with schizophrenia provided structural T1-weighted images acquired on a 3-Tesla MRI scanner and negative symptoms were evaluated using the Scale for the Assessment of Negative Symptoms. Voxel-based morphometry (VBM) was used to explore the correlations between whole-brain GM and i) Apathy, and ii) Affective Flattening, respectively. Apathy scores were negatively correlated with several GM clusters in frontal regions, including the frontal inferior operculum and the left dorsal anterior cingulate cortex. Only positive correlations with GM clusters were observed for Affective Flattening, particularly in the inferior temporal lobe. Notably, the regions associated with apathy scores were distinct from those associated with Affective Flattening, and these findings remained after controlling for antipsychotic medication dosage. We replicated previous associations between reduced frontal GM and apathy in patients with schizophrenia. Moreover, we demonstrated that these GM associations are distinct from those with Affective Flattening. The present findings set the stage for future larger-scale studies confirming the structural and neurochemical substrates of apathy in schizophrenia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Theory of Phase Separation and Polarization for Pure Ionic Liquids.

PubMed

Gavish, Nir; Yochelis, Arik

2016-04-07

Room temperature ionic liquids are attractive to numerous applications and particularly, to renewable energy devices. As solvent free electrolytes, they demonstrate a paramount connection between the material morphology and Coulombic interactions: the electrode/RTIL interface is believed to be a product of both polarization and spatiotemporal bulk properties. Yet, theoretical studies have dealt almost exclusively with independent models of morphology and electrokinetics. Introduction of a distinct Cahn-Hilliard-Poisson type mean-field framework for pure molten salts (i.e., in the absence of any neutral component), allows a systematic coupling between morphological evolution and the electrokinetic phenomena, such as transient currents. Specifically, linear analysis shows that spatially periodic patterns form via a finite wavenumber instability and numerical simulations demonstrate that while labyrinthine type patterns develop in the bulk, lamellar structures are favored near charged surfaces. The results demonstrate a qualitative phenomenology that is observed empirically and thus, provide a physically consistent methodology to incorporate phase separation properties into an electrochemical framework.

Morphological adaptation with no mitochondrial DNA differentiation in the coastal plain swamp sparrow

USGS Publications Warehouse

Greenberg, R.; Cordero, P.J.; Droege, S.; Fleischer, R.C.

1998-01-01

We estimated genetic differentiation between morphologically distinct tidal marsh populations of Swamp Sparrows (Melospiza georgiana nigrescens) and the more widespread inland populations (M. g. georgiana and M. g. ericrypta). The tidal marsh populations are consistently grayer with more extensive black markings (particularly in the crown), and their bills are larger. These differences are variously shared with other species of salt marsh birds and small mammals. We analyzed mitochondrial DNA sequences (5′ end of control region, COII/t-lys/ATPase8, and ND2) of Swamp Sparrows and found low levels of genetic variation and no evidence of geographic structure. These results suggest a rapid and recent geographic expansion of Swamp Sparrows from restricted Pleistocene populations. Morphological differentiation has occurred without long-term genetic isolation, suggesting that selection on the divergent traits is intense. The grayer and more melanistic plumage is probably cryptic coloration for foraging on tidal mud, which tends to be grayish as a result of the formation of iron sulfides, rather than iron oxides, under anaerobic conditions.

Fabrication and microstructures of functional gradient SiBCN–Nb composite by hot pressing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Min, E-mail: lcxsunmin@163.com; Fu, Ruoyu; Chen, Jun

2016-04-15

A functional gradient material with five layers composed of SiBCN ceramic and niobium (Nb) was prepared successfully by hot pressing. The phase composition, morphology features and microstructures were investigated in each layer of the gradient material. The Nb-containing compounds involving NbC, Nb{sub 6}C{sub 5}, Nb{sub 4}C{sub 3}, Nb{sub 5}Si{sub 3} and NbN increase with the volume fraction of Nb increasing in the sub-layer. They are randomly scattered (≤ 25 vol.% Nb), then strip-like, and finally distribute continuously (≥ 75 vol.% Nb). The size of BN(C) and SiC grains in Nb-containing layers is larger than in 100% SiBCN layer due tomore » the loss of the capsule-like structures. No distinct interfaces form in the transition regions indicating the gradual changes in phase composition and microstructures. - Highlights: • A functional gradient SiBCN–Nb material was prepared successfully by hot pressing. • Phase composition, morphology features and microstructures were investigated. • Thermodynamic calculation was used to aid in the phase analysis. • No distinct interfaces form typical of the functional gradient material.« less

Analysis of grain characters in temperate grasses reveals distinctive patterns of endosperm organization associated with grain shape

PubMed Central

Drea, Sinéad

2012-01-01

Members of the core pooids represent the most important crops in temperate zones including wheat, barley, and oats. Their importance as crops is largely due to the grain, particularly the storage capabilities of the endosperm. In this study, a comprehensive survey of grain morphology and endosperm organization in representatives of wild and cultivated species throughout the core pooids was performed. As sister to the core pooid tribes Poeae, Aveneae, Triticeae, and Bromeae within the Pooideae subfamily, Brachypodium provides a taxonomically relevant reference point. Using macroscopic, histological, and molecular analyses distinct patterns of grain tissue organization in these species, focusing on the peripheral and modified aleurone, are described. The results indicate that aleurone organization is correlated with conventional grain quality characters such as grain shape and starch content. In addition to morphological and organizational variation, expression patterns of candidate gene markers underpinning this variation were examined. Features commonly associated with grains are largely defined by analyses on lineages within the Triticeae and knowledge of grain structure may be skewed as a result of the focus on wheat and barley. Specifically, the data suggest that the modified aleurone is largely restricted to species in the Triticeae tribe. PMID:23081982

Dynamic mechanical oscillations during metamorphosis of the monarch butterfly

PubMed Central

Pelling, Andrew E; Wilkinson, Paul R; Stringer, Richard; Gimzewski, James K

2008-01-01

The mechanical oscillation of the heart is fundamental during insect metamorphosis, but it is unclear how morphological changes affect its mechanical dynamics. Here, the micromechanical heartbeat with the monarch chrysalis (Danaus plexippus) during metamorphosis is compared with the structural changes observed through in vivo magnetic resonance imaging (MRI). We employ a novel ultra-sensitive detection approach, optical beam deflection, in order to measure the microscale motions of the pupae during the course of metamorphosis. We observed very distinct mechanical contractions occurring at regular intervals, which we ascribe to the mechanical function of the heart organ. Motion was observed to occur in approximately 15 min bursts of activity with frequencies in the 0.4–1.0 Hz range separated by periods of quiescence during the first 83 per cent of development. In the final stages, the beating was found to be uninterrupted until the adult monarch butterfly emerged. Distinct stages of development were characterized by changes in frequency, amplitude, mechanical quality factor and de/repolarization times of the mechanical pulsing. The MRI revealed that the heart organ remains functionally intact throughout metamorphosis but undergoes morphological changes that are reflected in the mechanical oscillation. PMID:18682363

Pattern interpolation in thin films of lamellar, symmetric copolymers on nano-patterned substrates

NASA Astrophysics Data System (ADS)

Detcheverry, Francois; Nagpal, Umang; Liu, Guoliang; Nealey, Paul; de Pablo, Juan

2009-03-01

A molecular model of block copolymer systems is used to conduct a systematic study of the morphologies that arise when thin films of symmetric, lamellar forming block copolymer materials are deposited on nanopatterned surfaces. Over 500 distinct cases are considered. It is found that, in general, three distinct morphologies can arise depending on the strength of the substrate-polymer interactions, the film thickness, and the period of the substrate pattern. The relative stability of those morphologies is determined by direct calculation of the free energy differences. The dynamic propensity of those morphologies to emerge is examined by careful analysis of simulated trajectories. The results of this systematic study are used to interpret recent experimental data for films of polystyrene-PMMA copolymers on chemically nanopatterned surfaces.

Cross-Linguistic Variations in L2 Morphological Awareness.

ERIC Educational Resources Information Center

Koda, Keiko

2000-01-01

Investigated effects of first language processing on second language morphological awareness. Preliminary cross-linguistic comparisons indicated that morphological awareness in two typologically distinct languages, Chinese and English, differs in several major ways. Tested hypotheses from the study with two groups of English-as-a-Second-Language…

Integration of Brain and Skull in Prenatal Mouse Models of Apert and Crouzon Syndromes

PubMed Central

Motch Perrine, Susan M.; Stecko, Tim; Neuberger, Thomas; Jabs, Ethylin W.; Ryan, Timothy M.; Richtsmeier, Joan T.

2017-01-01

The brain and skull represent a complex arrangement of integrated anatomical structures composed of various cell and tissue types that maintain structural and functional association throughout development. Morphological integration, a concept developed in vertebrate morphology and evolutionary biology, describes the coordinated variation of functionally and developmentally related traits of organisms. Syndromic craniosynostosis is characterized by distinctive changes in skull morphology and perceptible, though less well studied, changes in brain structure and morphology. Using mouse models for craniosynostosis conditions, our group has precisely defined how unique craniosynostosis causing mutations in fibroblast growth factor receptors affect brain and skull morphology and dysgenesis involving coordinated tissue-specific effects of these mutations. Here we examine integration of brain and skull in two mouse models for craniosynostosis: one carrying the FGFR2c C342Y mutation associated with Pfeiffer and Crouzon syndromes and a mouse model carrying the FGFR2 S252W mutation, one of two mutations responsible for two-thirds of Apert syndrome cases. Using linear distances estimated from three-dimensional coordinates of landmarks acquired from dual modality imaging of skull (high resolution micro-computed tomography and magnetic resonance microscopy) of mice at embryonic day 17.5, we confirm variation in brain and skull morphology in Fgfr2cC342Y/+ mice, Fgfr2+/S252W mice, and their unaffected littermates. Mutation-specific variation in neural and cranial tissue notwithstanding, patterns of integration of brain and skull differed only subtly between mice carrying either the FGFR2c C342Y or the FGFR2 S252W mutation and their unaffected littermates. However, statistically significant and substantial differences in morphological integration of brain and skull were revealed between the two mutant mouse models, each maintained on a different strain. Relative to the effects of disease-associated mutations, our results reveal a stronger influence of the background genome on patterns of brain-skull integration and suggest robust genetic, developmental, and evolutionary relationships between neural and skeletal tissues of the head. PMID:28790902

Disentangling the role of hybridization in the evolution of the endangered Arizona cliffrose (Purshia subintegra; Rosaceae): A molecular and morphological analysis

USGS Publications Warehouse

Travis, S.E.; Baggs, J.E.; Maschinski, J.

2008-01-01

Hybridization may threaten the conservation status of rare species through genetic assimilation and may confound the ability to distinguish among taxa. We studied these issues in an endangered shrub, Purshia subintegra (Rosaceae), known from four populations growing on limestone outcrops in central Arizona (USA). Using amplified fragment length polymorphisms (AFLP) and the Bayesian clustering algorithm implemented in STRUCTURE, we identified three distinct genetic lineages among Arizona Purshia subintegra and P. stansburiana. An initial split divided San Carlos Basin P. subintegra (considered P. pinkavae by Schaack) from northern P. stansburiana populations (FST = 0.394). A subsequent split separated northern P. stansburiana from two P. subintegra populations at Horseshoe Lake and Burro Creek (FST = 0.207), which comprised a nearly perfect admixture of the two lineages identified in the initial analysis. In the Verde River Valley P. subintegra is sympatric with P. stansburiana and exhibited an average 27% P. stansburiana genes for 5 of 6 stands analyzed, indicating ongoing hybridization and backcrossing with P. subintegra. Individuals carrying >90% P. subintegra markers are identifiable 68% of the time based on morphology, with leaf lobing, leaf size, and leaf length acting as the most reliable indicators of taxonomic status. However, the genetic and morphological distance correlation among individuals was low (r = 0.17, P = 0.0002), indicating that morphology cannot always accurately predict genetic admixture or taxonomy. Overall, our study confirmed the genetic distinctiveness of the San Carlos Basin population, an ancient natural hybrid origin of P. subintegra, and the presence of a hybrid swarm in the Verde Valley, whose conservation value may lie in its heightened genetic diversity. ?? 2007 Springer Science+Business Media B.V.

Flume experiments elucidate relationships between stream morphology, hyporheic residence time, and nitrous oxide production

NASA Astrophysics Data System (ADS)

Quick, Annika; Farrell, Tiffany B.; Reeder, William Jeffrey; Feris, Kevin P.; Tonina, Daniele; Benner, Shawn G.

2015-04-01

The hyporheic zone is a potentially important producer of nitrous oxide, a powerful greenhouse gas. The location and magnitude of nitrous oxide generation within the hyporheic zone involves complex interactions between multiple nitrogen species, redox conditions, microbial communities, and hydraulics. To better understand nitrous oxide generation and emissions from streams, we conducted large-scale flume experiments in which we monitored pore waters along hyporheic flow paths within stream dune structures. Measurements of dissolved oxygen, ammonia, nitrate, nitrite, and dissolved nitrous oxide showed distinct spatial relationships reflecting redox changes along flow paths. Using residence times along a flow path, clear trends in oxygen conditions and nitrogen species were observed. Three dune sizes were modeled, resulting in a range of residence times, carbon reactivity levels and respiration rates. We found that the magnitude and location of nitrous oxide production in the hyporheic zone is related to nitrate loading, dune morphology, and residence time. Specifically, increasing exogenous nitrate levels in surface water to approximately 3 mg/L resulted in an increase in dissolved N2O concentrations greater than 500% (up to 10 µg/L N-N2O) in distinct zones of specific residence times. We also found, however, that dissolved N2O concentrations decreased to background levels further along the flow path due to either reduction of nitrous oxide to dinitrogen gas or degassing. The decrease in measurable N2O along a flow path strongly suggests an important relationship between dune morphology, residence time, and nitrous oxide emissions from within stream sediments. Relating streambed morphology and loading of nitrogen species allows for prediction of nitrous oxide production in the hyporheic zone of natural systems.

Natural Microbial Assemblages Reflect Distinct Organismal and Functional Partitioning

NASA Astrophysics Data System (ADS)

Wilmes, P.; Andersson, A.; Kalnejais, L. H.; Verberkmoes, N. C.; Lefsrud, M. G.; Wexler, M.; Singer, S. W.; Shah, M.; Bond, P. L.; Thelen, M. P.; Hettich, R. L.; Banfield, J. F.

2007-12-01

The ability to link microbial community structure to function has long been a primary focus of environmental microbiology. With the advent of community genomic and proteomic techniques, along with advances in microscopic imaging techniques, it is now possible to gain insights into the organismal and functional makeup of microbial communities. Biofilms growing within highly acidic solutions inside the Richmond Mine (Iron Mountain, Redding, California) exhibit distinct macro- and microscopic morphologies. They are composed of microorganisms belonging to the three domains of life, including archaea, bacteria and eukarya. The proportion of each organismal type depends on sampling location and developmental stage. For example, mature biofilms floating on top of acid mine drainage (AMD) pools exhibit layers consisting of a densely packed bottom layer of the chemoautolithotroph Leptospirillum group II, a less dense top layer composed mainly of archaea, and fungal filaments spanning across the entire biofilm. The expression of cytochrome 579 (the most highly abundant protein in the biofilm, believed to be central to iron oxidation and encoded by Leptospirillum group II) is localized at the interface of the biofilm with the AMD solution, highlighting that biofilm architecture is reflected at the functional gene expression level. Distinct functional partitioning is also apparent in a biological wastewater treatment system that selects for distinct polyphosphate accumulating organisms. Community genomic data from " Candidatus Accumulibacter phosphatis" dominated activated sludge has enabled high mass-accuracy shotgun proteomics for identification of key metabolic pathways. Comprehensive genome-wide alignment of orthologous proteins suggests distinct partitioning of protein variants involved in both core-metabolism and specific metabolic pathways among the dominant population and closely related species. In addition, strain- resolved proteogenomic analysis of the AMD biofilms also highlights the importance of strain heterogeneity for the maintenance of community structure and function. These findings explain the importance of genetic diversity in facilitating the stable performance of complex microbial processes. Furthermore, although very different in terms of habitat, both microbial communities exhibit distinct functional compartmentalization and demonstrate its role in sustaining microbial community structure.

Using Airborne Radar Stratigraphy to Model Surface Accumulation Anomaly and Basal Control over Deformed Basal Ice in Greenland

NASA Astrophysics Data System (ADS)

Das, I.; Bell, R. E.; Creyts, T. T.; Wolovick, M.

2013-12-01

Large deformed ice structures have been imaged at the base of northern Greenland ice sheet by IceBridge airborne radar. Numerous deformed structures lie along the base of both Petermann Glacier and Northeast Ice stream catchments covering 10-13% of the catchment area. These structures may be combinations of basal freeze-on and folded ice that overturns and inverts stratigraphy. In the interior, where the ice velocity is low, the radar imaged height of the deformed structures are frequently a significant fraction of the ice thickness. They are related to basal freeze on and stick-slip at the base of the ice sheet and may be triggered by subglacial water, sediments or local geological conditions. The larger ones (at times up to 700 m thick and 140 km long) perturb the ice stratigraphy and create prominent undulations on the ice surface and modify the local surface mass balance. Here, we investigate the relationship between the deformed structures and surface processes using shallow and deep ice radar stratigraphy. The surface undulations caused by the deformed structures modulate the pattern of local surface snow accumulation. Using normalized differences of several near-surface stratigraphic layers, we have calculated the accumulation anomaly over these deformed structures. The accumulation anomalies can be as high as 20% of the local surface accumulation over some of the larger surface depressions caused by these deformed structures. We observe distinct differences in the phases of the near-surface internal layers on the Petermann and Northeast catchments. These differences indicate that the deformed bodies over Petermann are controlled by conditions at the bed different from the Northeast Ice stream. The distinctly different near-surface stratigraphy over the deformed structures in the Petermann and Northeast catchments have opened up a number of questions including their formation and how they influence the ice dynamics, ice stratigraphy and surface mass balance. In this study we will model the different physical conditions at the bed and ice rheology from their distinct signatures in the near-surface strata. The results will identify the distinct mechanisms that form these bodies and their control over the surface morphology and snow accumulation.

Premature Aging Phenotype in Mice Lacking High-Affinity Nicotinic Receptors: Region-Specific Changes in Layer V Pyramidal Cell Morphology.

PubMed

Konsolaki, Eleni; Skaliora, Irini

2015-08-01

The mechanisms by which aging leads to alterations in brain structure and cognitive deficits are unclear. Α deficient cholinergic system has been implicated as one of the main factors that could confer a heightened vulnerability to the aging process, and mice lacking high-affinity nicotinic receptors (β2(-/-)) have been proposed as an animal model of accelerated cognitive aging. To date, however, age-related changes in neuronal microanatomy have not been studied in these mice. In the present study, we examine the neuronal structure of yellow fluorescent protein (YFP(+)) layer V neurons in 2 cytoarchitectonically distinct cortical regions in wild-type (WT) and β2(-/-) animals. We find that (1) substantial morphological differences exist between YFP(+) cells of the anterior cingulate cortex (ACC) and primary visual cortex (V1), in both genotypes; (2) in WT animals, ACC cells are more susceptible to aging compared with cells in V1; and (3) β2 deletion is associated with a regionally and temporally specific increase in vulnerability to aging. ACC cells exhibit a prematurely aged phenotype already at 4-6 months, whereas V1 cells are spared in adulthood but strongly affected in old animals. Collectively, our data reveal region-specific synergistic effects of aging and genotype and suggest distinct vulnerabilities in V1 and ACC neurons. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

MAGNETIC FIELD OF THE VELA C MOLECULAR CLOUD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusune, Takayoshi; Sugitani, Koji; Nakamura, Fumitaka

We have performed extensive near-infrared ( JHK {sub s}) imaging polarimetry toward the Vela C molecular cloud, which covers the five high-density sub-regions (North, Centre-Ridge, Centre-Nest, South-Ridge, and South-Nest) with distinct morphological characteristics. The obtained polarization vector map shows that three of these sub-regions have distinct plane-of-the-sky (POS) magnetic-field characteristics according to the morphological characteristics. (1) In the Centre-Ridge sub-region, a dominating ridge, the POS magnetic field is mostly perpendicular to the ridge. (2) In the Centre-Nest sub-region, a structure having a slightly extended nest of filaments, the POS magnetic field is nearly parallel to its global elongation. (3) Inmore » the South-Nest sub-region, which has a network of small filaments, the POS magnetic field appears to be chaotic. By applying the Chandrasekhar–Fermi method, we derived the POS magnetic field strength as ∼70–310 μ G in the Centre-Ridge, Centre-Nest, and South-Ridge sub-regions. In the South-Nest sub-region, the dispersion of polarization angles is too large to apply the C-F method. Because the velocity dispersion in this sub-region is not greater than those in the other sub-regions, we suggest that the magnetic field in this sub-region is weaker than those in other sub-regions. We also discuss the relationship between the POS magnetic field (configuration and strength) and the cloud structure of each sub-region.« less

Aging the oldest turtles: the placodont affinities of Priscochelys hegnabrunnensis

NASA Astrophysics Data System (ADS)

Scheyer, Torsten M.

2008-09-01

Priscochelys hegnabrunnensis, a fragmentary piece of armour shell from the Muschelkalk of Germany (Upper Triassic) with few diagnostic morphological features, was recently proposed to represent the oldest known stem turtle. As such, the specimen is of high importance because it shifts the date of the first appearance of turtles back about 20 Ma, which equals about 10% of the total stratigraphic range of the group. In this paper, I present new morphologic, histologic and neutron tomographic (NT) data that relate to the microstructure of the bone of the specimen itself. In opposition to the previous morphologic descriptions, P. hegnabrunnensis was found to share several distinctive features (i.e. bone sutures congruent with scute sulci, absence of a diploe structure with interior cancellous bone, thin vascular canals radiating outwards from distinct centres in each field and rugose ventral bone surface texture consisting of mineralised fibre bundles) with cyamodontoid placodonts (Diapsida: Sauropterygia) and fewer with stem turtles (i.e. depth of sulci). Two aspects that were previously thought to be relevant for the assignment to the turtle stem (conical scutes and presence of foramina) are argued to be of dubious value. P. hegnabrunnensis is proposed to represent a fragmentary piece of cyamodontoid armour consisting of fused conical plates herein. The specimen is not a part of the turtle stem and thus does not represent the oldest turtle. Accordingly, P. hegnabrunnensis does not shorten the ghost lineage to the potential sister group of turtles.

Aging the oldest turtles: the placodont affinities of Priscochelys hegnabrunnensis.

PubMed

Scheyer, Torsten M

2008-09-01

Priscochelys hegnabrunnensis, a fragmentary piece of armour shell from the Muschelkalk of Germany (Upper Triassic) with few diagnostic morphological features, was recently proposed to represent the oldest known stem turtle. As such, the specimen is of high importance because it shifts the date of the first appearance of turtles back about 20 Ma, which equals about 10% of the total stratigraphic range of the group. In this paper, I present new morphologic, histologic and neutron tomographic (NT) data that relate to the microstructure of the bone of the specimen itself. In opposition to the previous morphologic descriptions, P. hegnabrunnensis was found to share several distinctive features (i.e. bone sutures congruent with scute sulci, absence of a diploe structure with interior cancellous bone, thin vascular canals radiating outwards from distinct centres in each field and rugose ventral bone surface texture consisting of mineralised fibre bundles) with cyamodontoid placodonts (Diapsida: Sauropterygia) and fewer with stem turtles (i.e. depth of sulci). Two aspects that were previously thought to be relevant for the assignment to the turtle stem (conical scutes and presence of foramina) are argued to be of dubious value. P. hegnabrunnensis is proposed to represent a fragmentary piece of cyamodontoid armour consisting of fused conical plates herein. The specimen is not a part of the turtle stem and thus does not represent the oldest turtle. Accordingly, P. hegnabrunnensis does not shorten the ghost lineage to the potential sister group of turtles.

External tufted cells in the main olfactory bulb form two distinct subpopulations.

PubMed

Antal, Miklós; Eyre, Mark; Finklea, Bryson; Nusser, Zoltan

2006-08-01

The glomeruli of the main olfactory bulb are the first processing station of the olfactory pathway, where complex interactions occur between sensory axons, mitral cells and a variety of juxtaglomerular neurons, including external tufted cells (ETCs). Despite a number of studies characterizing ETCs, little is known about how their morphological and functional properties correspond to each other. Here we determined the active and passive electrical properties of ETCs using in vitro whole-cell recordings, and correlated them with their dendritic arborization patterns. Principal component followed by cluster analysis revealed two distinct subpopulations of ETCs based on their electrophysiological properties. Eight out of 12 measured physiological parameters exhibited significant difference between the two subpopulations, including the membrane time constant, amplitude of spike afterhyperpolarization, variance in the interspike interval distribution and subthreshold resonance. Cluster analysis of the morphological properties of the cells also revealed two subpopulations, the most prominent dissimilarity between the groups being the presence or absence of secondary, basal dendrites. Finally, clustering the cells taking all measured properties into account also indicated the presence of two subpopulations that mapped in an almost perfect one-to-one fashion to both the physiologically and the morphologically derived groups. Our results demonstrate that a number of functional and structural properties of ETCs are highly predictive of one another. However, cells within each subpopulation exhibit pronounced variability, suggesting a large degree of specialization evolved to fulfil specific functional requirements in olfactory information processing.

External tufted cells in the main olfactory bulb form two distinct subpopulations

PubMed Central

Antal, Miklós; Eyre, Mark; Finklea, Bryson; Nusser, Zoltan

2006-01-01

The glomeruli of the main olfactory bulb are the first processing station of the olfactory pathway, where complex interactions occur between sensory axons, mitral cells and a variety of juxtaglomerular neurons, including external tufted cells (ETCs). Despite a number of studies characterizing ETCs, little is known about how their morphological and functional properties correspond to each other. Here we determined the active and passive electrical properties of ETCs using in vitro whole-cell recordings, and correlated them with their dendritic arborization patterns. Principal component followed by cluster analysis revealed two distinct subpopulations of ETCs based on their electrophysiological properties. Eight out of 12 measured physiological parameters exhibited significant difference between the two subpopulations, including the membrane time constant, amplitude of spike afterhyperpolarization, variance in the interspike interval distribution and subthreshold resonance. Cluster analysis of the morphological properties of the cells also revealed two subpopulations, the most prominent dissimilarity between the groups being the presence or absence of secondary, basal dendrites. Finally, clustering the cells taking all measured properties into account also indicated the presence of two subpopulations that mapped in an almost perfect one-to-one fashion to both the physiologically and the morphologically derived groups. Our results demonstrate that a number of functional and structural properties of ETCs are highly predictive of one another. However, cells within each subpopulation exhibit pronounced variability, suggesting a large degree of specialization evolved to fulfil specific functional requirements in olfactory information processing. PMID:16930438

Genetic backgrounds and redox conditions influence morphological characteristics and cell differentiation of osteoclasts in mice.

PubMed

Narahara, Shun; Matsushima, Haruna; Sakai, Eiko; Fukuma, Yutaka; Nishishita, Kazuhisa; Okamoto, Kuniaki; Tsukuba, Takayuki

2012-04-01

Osteoclasts (OCLs) are multinucleated giant cells and are formed by the fusion of mononuclear progenitors of monocyte/macrophage lineage. It is known that macrophages derived from different genetic backgrounds exhibit quite distinct characteristics of immune responses. However, it is unknown whether OCLs from different genetic backgrounds show distinct characteristics. In this study, we showed that bone-marrow macrophages (BMMs) derived from C57BL/6, BALB/c and ddY mice exhibited considerably distinct morphological characteristics and cell differentiation into OCLs. The differentiation of BMMs into OCLs was comparatively quicker in the C57BL/6 and ddY mice, while that of BALB/c mice was rather slow. Morphologically, ddY OCLs showed a giant cell with a round shape, C57BL/6 OCLs were of a moderate size with many protrusions and BALB/c OCLs had the smallest size with fewer nuclei. The intracellular signaling of differentiation and expression levels of marker proteins of OCLs were different in the respective strains. Treatment of BMMs from the three different strains with the reducing agent N-acetylcysteine (NAC) or with the oxidation agent hydrogen peroxide (H(2)O(2)) induced changes in the shape and sizes of the cells and caused distinct patterns of cell differentiation and survival. Thus, genetic backgrounds and redox conditions regulate the morphological characteristics and cell differentiation of OCLs.

Perimysial fibroblasts of extraocular muscle, as unique as the muscle fibers.

PubMed

Kusner, Linda L; Young, Andrew; Tjoe, Steven; Leahy, Patrick; Kaminski, Henry J

2010-01-01

Extraocular muscle (EOM) has a distinct skeletal muscle phenotype. The hypothesis for the study was that fibroblasts support the unique EOM phenotype and that perimysial fibroblasts derived from EOM have properties that distinguish them from fibroblasts derived from other skeletal muscle. Perimysial fibroblasts from leg muscle (LM-Fibro) and EOM (EOM-Fibro) of mice were derived and maintained in culture. EOM- and LM-Fibro were assessed morphologically and for vimentin, smooth muscle actin, and Thy-1 immunoreactivity. DNA microarray analysis was performed on LM- and EOM-Fibro grown in conditions that support myoblast differentiation. To assess trophic interactions, co-cultures of myoblasts from established cell lines, CL-EOM and CL-LM with, EOM- or LM-Fibro were performed in direct contact and in a permeable filter support culture. The degree of myotube maturation was assessed by the percentage of myotubes with more than three myonuclei per myotube. EOM- and LM-Fibro cells exhibited distinct morphologies. Both cell types proliferated as a monolayer and expressed vimentin. Fifty-five percent (SD 4.4%) of EOM-Fibro were Thy-1 positive compared with only 24% (SD 4.4%) of LM-Fibro. DNA microarray analysis demonstrated differential expression of structural, immune response, and metabolism-related genes between EOM- and LM-Fibro. Co-cultures demonstrated that mature myotube formation in EOM-derived cell lines was supported to a greater extent by EOM-Fibro than by LM-Fibro, compared with CL-EOM grown with LM-Fibro. Fibroblasts from EOM demonstrate distinct properties that distinguish them from leg muscle-derived fibroblasts. The distinct properties of EOM-Fibro may support the unique EOM phenotype and contribute to their differential involvement in disease.

Does structural complexity determine the morphology of assemblages? An experimental test on three continents.

PubMed

Gibb, Heloise; Parr, Catherine L

2013-01-01

Understanding how species will respond to global change depends on our ability to distinguish generalities from idiosyncrasies. For diverse, but poorly known taxa, such as insects, species traits may provide a short-cut to predicting species turnover. We tested whether ant traits respond consistently to habitat complexity across geographically independent ant assemblages, using an experimental approach and baits. We repeated our study in six paired simple and complex habitats on three continents with distinct ant faunas. We also compared traits amongst ants with different foraging strategies. We hypothesised that ants would be larger, broader, have longer legs and more dorsally positioned eyes in simpler habitats. In agreement with predictions, ants had longer femurs and dorsally positioned eyes in simple habitats. This pattern was most pronounced for ants that discovered resources. Body size and pronotum width responded as predicted for experimental treatments, but were inconsistent across continents. Monopolising ants were smaller, with shorter femurs than those that occupied or discovered resources. Consistent responses for several traits suggest that many, but not all, aspects of morphology respond predictably to habitat complexity, and that foraging strategy is linked with morphology. Some traits thus have the potential to be used to predict the direction of species turnover, changes in foraging strategy and, potentially, evolution in response to changes in habitat structure.

Carbon nanotube-templated assembly of regioregular poly(3-alkylthiophene) in solution

NASA Astrophysics Data System (ADS)

Zhu, Jiahua; Stevens, Eric; He, Youjun; Hong, Kunlun; Ivanov, Ilia

2016-09-01

Control of structural heterogeneity by rationally encoding of the molecular assemblies is a key enabling design of hierarchical, multifunctional materials of the future. Here we report the strategies to gain such control using solution- based assembly to construct a hybrid nano-assembly and a network hybrid structure of regioregular poly(3- alkylthiophene) - carbon nanotube (P3AT-CNT). The opto-electronic performance of conjugated polymer (P3AT) is defined by the structure of the aggregate in solution and in the solid film. Control of P3AT aggregation would allow formation of broad range of morphologies with very distinct electro-optical. We utilize interactive templating to confine the assembly behavior of conjugated polymers, replacing poorly controlled solution processing approach. Perfect crystalline surface of the single-walled and multi-walled carbon nanotube (SWCNT/MWCNT) acts as a template, seeding P3AT aggregation of the surface of the nanotube. The seed continues directional growth through pi-pi stacking leading to the formation of to well-defined P3AT-CNT morphologies, including comb-like nano-assemblies, super- structures and gel networks. Interconnected, highly-branched network structure of P3AT-CNT hybrids is of particular interest to enable efficient, long-range, balanced charge carrier transport. The structure and opto-electionic function of the intermediate assemblies and networks of P3AT/CNT hybrids are characterized by transmission election microscopy and UV-vis absorption.

Does morphology predict trophic niche differentiation? Relationship between feeding habits and body shape in four co-occurring juvenile species (Pisces: Perciformes, Sparidae)

NASA Astrophysics Data System (ADS)

Ventura, Daniele; Bonhomme, Vincent; Colangelo, Paolo; Bonifazi, Andrea; Jona Lasinio, Giovanna; Ardizzone, Giandomenico

2017-05-01

Feeding habits, diet overlap and morphological correlates of four juvenile species of the genus Diplodus were investigated during their settlement periods, along the Tyrrhenian coast. Stomach content analysis showed that the diets of D. sargus and D. puntazzo mainly comprised benthic prey such as harpacticoid copepods, amphipods and polychaetes. On the other hand, D. vulgaris and D. annularis fed mainly on planktonic prey such as ciclopoids, calanoids copepods and fish larvae. A biologically significant diet overlap, calculated using the Schoener index, was recorded between D. sargus and D. puntazzo and between D. vulgaris and D. annularis. Morphological characters related to feeding such as gape height and gut length with their relative growth patterns suggested that different trophic preferences have led to a morphological diversification of feeding structures. Therefore, a geometric morphometric outline method, namely Elliptic Fourier Analysis (EFA) was used to examine shape modification of the head and body regions. The multivariate analyses performed on shape descriptors demonstrated that the four species were morphologically distinct due to different feeding habits: the two species which feed mainly on benthic prey presented a discoidal shape, with broad profiles and rounded head; by contrast, the other two species which relied mostly on planktonic prey, presented a streamlined and more elongated body shape.

Seafloor heterogeneity influences the biodiversity–ecosystem functioning relationships in the deep sea

PubMed Central

Zeppilli, Daniela; Pusceddu, Antonio; Trincardi, Fabio; Danovaro, Roberto

2016-01-01

Theoretical ecology predicts that heterogeneous habitats allow more species to co-exist in a given area. In the deep sea, biodiversity is positively linked with ecosystem functioning, suggesting that deep-seabed heterogeneity could influence ecosystem functions and the relationships between biodiversity and ecosystem functioning (BEF). To shed light on the BEF relationships in a heterogeneous deep seabed, we investigated variations in meiofaunal biodiversity, biomass and ecosystem efficiency within and among different seabed morphologies (e.g., furrows, erosional troughs, sediment waves and other depositional structures, landslide scars and deposits) in a narrow geo-morphologically articulated sector of the Adriatic Sea. We show that distinct seafloor morphologies are characterized by highly diverse nematode assemblages, whereas areas sharing similar seabed morphologies host similar nematode assemblages. BEF relationships are consistently positive across the entire region, but different seabed morphologies are characterised by different slope coefficients of the relationship. Our results suggest that seafloor heterogeneity, allowing diversified assemblages across different habitats, increases diversity and influence ecosystem processes at the regional scale, and BEF relationships at smaller spatial scales. We conclude that high-resolution seabed mapping and a detailed analysis of the species distribution at the habitat scale are crucial for improving management of goods and services delivered by deep-sea ecosystems. PMID:27211908

Distinct roles of cell wall biogenesis in yeast morphogenesis as revealed by multivariate analysis of high-dimensional morphometric data

PubMed Central

Okada, Hiroki; Ohnuki, Shinsuke; Roncero, Cesar; Konopka, James B.; Ohya, Yoshikazu

2014-01-01

The cell wall of budding yeast is a rigid structure composed of multiple components. To thoroughly understand its involvement in morphogenesis, we used the image analysis software CalMorph to quantitatively analyze cell morphology after treatment with drugs that inhibit different processes during cell wall synthesis. Cells treated with cell wall–affecting drugs exhibited broader necks and increased morphological variation. Tunicamycin, which inhibits the initial step of N-glycosylation of cell wall mannoproteins, induced morphologies similar to those of strains defective in α-mannosylation. The chitin synthase inhibitor nikkomycin Z induced morphological changes similar to those of mutants defective in chitin transglycosylase, possibly due to the critical role of chitin in anchoring the β-glucan network. To define the mode of action of echinocandin B, a 1,3-β-glucan synthase inhibitor, we compared the morphology it induced with mutants of Fks1 that contains the catalytic domain for 1,3-β-glucan synthesis. Echinocandin B exerted morphological effects similar to those observed in some fks1 mutants, with defects in cell polarity and reduced glucan synthesis activity, suggesting that echinocandin B affects not only 1,3-β-glucan synthesis, but also another functional domain. Thus our multivariate analyses reveal discrete functions of cell wall components and increase our understanding of the pharmacology of antifungal drugs. PMID:24258022

VARSEDIG: an algorithm for morphometric characters selection and statistical validation in morphological taxonomy.

PubMed

Guisande, Cástor; Vari, Richard P; Heine, Jürgen; García-Roselló, Emilio; González-Dacosta, Jacinto; Perez-Schofield, Baltasar J García; González-Vilas, Luis; Pelayo-Villamil, Patricia

2016-09-12

We present and discuss VARSEDIG, an algorithm which identifies the morphometric features that significantly discriminate two taxa and validates the morphological distinctness between them via a Monte-Carlo test. VARSEDIG is freely available as a function of the RWizard application PlotsR (http://www.ipez.es/RWizard) and as R package on CRAN. The variables selected by VARSEDIG with the overlap method were very similar to those selected by logistic regression and discriminant analysis, but overcomes some shortcomings of these methods. VARSEDIG is, therefore, a good alternative by comparison to current classical classification methods for identifying morphometric features that significantly discriminate a taxon and for validating its morphological distinctness from other taxa. As a demonstration of the potential of VARSEDIG for this purpose, we analyze morphological discrimination among some species of the Neotropical freshwater family Characidae.

Effects of annealing temperature and duration on the morphological and optical evolution of self-assembled Pt nanostructures on c-plane sapphire.

PubMed

Sui, Mao; Li, Ming-Yu; Kunwar, Sundar; Pandey, Puran; Zhang, Quanzhen; Lee, Jihoon

2017-01-01

Metallic nanostructures (NSs) have been widely adapted in various applications and their physical, chemical, optical and catalytic properties are strongly dependent on their surface morphologies. In this work, the morphological and optical evolution of self-assembled Pt nanostructures on c-plane sapphire (0001) is demonstrated by the control of annealing temperature and dwelling duration with the distinct thickness of Pt films. The formation of Pt NSs is led by the surface diffusion, agglomeration and surface and interface energy minimization of Pt thin films, which relies on the growth parameters such as system temperature, film thickness and annealing duration. The Pt layer of 10 nm shows the formation of overlaying NPs below 650°C and isolated Pt nanoparticles above 700°C based on the enhanced surface diffusion and Volmer-Weber growth model whereas larger wiggly nanostructures are formed with 20 nm thick Pt layers based on the coalescence growth model. The morphologies of Pt nanostructures demonstrate a sharp distinction depending on the growth parameters applied. By the control of dwelling duration, the gradual transition from dense Pt nanoparticles to networks-like and large clusters is observed as correlated to the Rayleigh instability and Ostwald ripening. The various Pt NSs show a significant distinction in the reflectance spectra depending on the morphology evolution: i.e. the enhancement in UV-visible and NIR regions and the related optical properties are discussed in conjunction with the Pt NSs morphology and the surface coverage.

Ultrastructure of the filiform papillae on the tongue of the hamster.

PubMed Central

Fernandez, B; Suarez, I; Zapata, A

1978-01-01

The fine structure of the filiform papillae on the hamster tongue is described level by level from the basal layer to the surface. We did not observe two distinct types of cells with different morphology or components which could be held responsible for the production of two different types of keratin as have been described in other animals, but rather a uniformity of cell structures in each layer and only the so-called "smooth" type of keratin. However, keratin granules were more abundant in the anterior part of the papilla. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 PMID:689988

The Structural Properties and Stability of Monoclonal Antibodies at Freezing Conditions

NASA Astrophysics Data System (ADS)

Perevozchikova, Tatiana; Zarraga, Isidro; Scherer, Thomas; Wagner, Norman; Liu, Yun

2013-03-01

Monoclonal Antibodies (MAb) have become a crucial therapeutic agent in a number of anti-cancer treatments. Due to the inherent unstable nature of proteins in an aqueous formulation, a freeze-drying method has been developed to maintain long-term stability of biotherapeutics. The microstructural changes in Mabs during freezing, however, remain not fully described, and it was proposed that the formed morphology of freeze drying samples could affect the final product quality after reconstitution. Furthermore, it is well known that proteins tend to aggregate during the freezing process if a careful processing procedure is not formulated. Small Angle Neutron Scattering (SANS) is a powerful tool to investigate the structural properties and interactions of Mabs during various stages of lyophilization in situ. Here we present the SANS results of freeze-thaw studies on two MAbs at several different freezing temperatures. While the chosen proteins share a significant sequence homology, their freezing properties are found to be strikingly distinctive. We also show the effect of excipients, concentration and quenching speed on the final morphology of the frozen samples. These findings provide critical information for more effective lyophilization schemes for therapeutic proteins, as well as increase our understanding on structural properties of proteins under cryogenic conditions.

Structure, composition and morphology of bioactive titanate layer on porous titanium surfaces

NASA Astrophysics Data System (ADS)

Li, Jinshan; Wang, Xiaohua; Hu, Rui; Kou, Hongchao

2014-07-01

A bioactive coating was produced on pore surfaces of porous titanium samples by an amendatory alkali-heat treatment method. Porous titanium was prepared by powder metallurgy and its porosity and average size were 45% and 135 μm, respectively. Coating morphology, coating structure and phase constituents were examined by SEM, XPS and XRD. It was found that a micro-network structure with sizes of <200 nm mainly composed of bioactive sodium titanate and rutile phases of TiO2 covered the interior and exterior of porous titanium cells, and redundant Ca ion was detected in the titanate layer. The concentration distribution of Ti, O, Ca and Na in the coating showed a compositional gradient from the intermediate layer toward the outer surface. These compositional gradients indicate that the coating bonded to Ti substrate without a distinct interface. After immersion into the SBF solution for 3 days, a bone-like carbonate-hydroxylapatite showing a good biocompatibility was detected on the coating surface. And the redundant Ca advanced the bioactivity of the coating. Thus, the present modification is expected to allow the use of the bioactive porous titanium as artificial bones even under load-bearing conditions.

Diversity of exophillic acid derivatives in strains of an endophytic Exophiala sp.

PubMed

Cheikh-Ali, Zakaria; Glynou, Kyriaki; Ali, Tahir; Ploch, Sebastian; Kaiser, Marcel; Thines, Marco; Bode, Helge B; Maciá-Vicente, Jose G

2015-10-01

Members of the fungal genus Exophiala are common saprobes in soil and water environments, opportunistic pathogens of animals, or endophytes in plant roots. Their ecological versatility could imply a capacity to produce diverse secondary metabolites, but only a few studies have aimed at characterizing their chemical profiles. Here, we assessed the secondary metabolites produced by five Exophiala sp. strains of a particular phylotype, isolated from roots of Microthlaspi perfoliatum growing in different European localities. Exophillic acid and two previously undescribed compounds were isolated from these strains, and their structures were elucidated by spectroscopic methods using MS, 1D and 2D NMR. Bioassays revealed a weak activity of these compounds against disease-causing protozoa and mammalian cells. In addition, 18 related structures were identified by UPLC/MS based on comparisons with the isolated structures. Three Exophiala strains produced derivatives containing a β-d-glucopyranoside moiety, and their colony morphology was distinct from the other two strains, which produced derivatives lacking β-d-glucopyranoside. Whether the chemical/morphological strain types represent variants of the same genotype or independent genetic populations within Exophiala remains to be evaluated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analysis of very-high-resolution Galileo images of Europa: Implications for small-scale structure and surface evolution

NASA Astrophysics Data System (ADS)

Leonard, E. J.; Pappalardo, R. T.; Yin, A.; Prockter, L. M.; Patthoff, D. A.

2014-12-01

The Galileo Solid State Imager (SSI) recorded nine very high-resolution frames (8 at 12 m/pixel and 1 at 6 m/pixel) during the E12 flyby of Europa in Dec. 1997. To understand the implications for the small-scale structure and evolution of Europa, we mosaicked these frames (observations 12ESMOTTLE01 and 02, incidence ≈18°, emission ≈77°) into their regional context (part of observation 11ESREGMAP01, 220 m/pixel, incidence ≈74°, emission ≈23°), despite their very different viewing and lighting conditions. We created a map of geological units based on morphology, structure, and albedo along with stereoscopic images where the frames overlapped. The highly diverse units range from: high albedo sub-parallel ridge and grooved terrain; to variegated-albedo hummocky terrain; to low albedo and relatively smooth terrain. We classified and analyzed the diverse units solely based on the high-resolution image mosaic, prior to comparison to the context image, to obtain an in-depth look at possible surface evolution and underlying formational processes. We infer that some of these units represent different stages and forms of resurfacing, including cryovolcanic and tectonic resurfacing. However, significant morphological variation among units in the region indicates that there are different degrees of resurfacing at work. We have created candidate morphological sequences that provide insight into the conversion of ridged plains to chaotic terrain—generally, a process of subduing formerly sharp features through tectonic modification and/or cryovolcanism. When the map of the high-resolution area is compared to the regional context, features that appear to be one unit at regional resolution are comprised of several distinct units at high resolution, and features that appear to be smooth in the context image are found to show distinct textures. Moreover, in the context image, transitions from ridged units to disrupted units appear to be gradual; however the high-resolution image reveals them to be abrupt, suggesting tectonic control of these boundaries. These discrepancies could have important implications for a future landed exploration.

On the polymorphic and morphological changes of cellulose nanocrystals (CNC-I) upon mercerization and conversion to CNC-II.

PubMed

Jin, Ersuo; Guo, Jiaqi; Yang, Fang; Zhu, Yangyang; Song, Junlong; Jin, Yongcan; Rojas, Orlando J

2016-06-05

Polymorphic and morphological transformations of cellulosic materials are strongly associated to their properties and applications, especially in the case of emerging nanocelluloses. Related changes that take place upon treatment of cellulose nanocrystals (CNC) in alkaline conditions are studied here by XRD, TEM, AFM, and other techniques. The results indicate polymorphic transformation of CNC proceeds gradually in a certain range of alkali concentrations, i.e. from about 8% to 12.5% NaOH. In such transition alkali concentration, cellulose I and II allomorphs coexists. Such value and range of the transition concentration is strongly interdependent with the crystallite size of CNCs. In addition, it is distinctively lower than that for macroscopic fibers (12-15% NaOH). Transmission electron microscopy and particle sizing reveals that after mercerization CNCs tend to associate. Furthermore, TEMPO-oxidized mercerized CNC reveals the morphology of individual nanocrystal of the cellulose II type, which is composed of some interconnected granular structures. Overall, this work reveals how the polymorphism and morphology of individual CNC change in alkali conditions and sheds light onto the polymorphic transition from cellulose I to II. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of surface morphology on adsorption of potassium stearate molecules on diamond-like carbon substrate: A molecular dynamics study

NASA Astrophysics Data System (ADS)

Guo, Shusen; Cao, Yongzhi; Sun, Tao; Zhang, Junjie; Gu, Le; Zhang, Chuanwei; Xu, Zhiqiang

2018-05-01

Molecular dynamics (MD) simulations were used to provide insights into the influence of nano-scale surface morphology on adsorptive behavior of Potassium stearate molecules on diamond-like carbon (DLC) substrates. Particular focus was given to explain that how the distinctive geometric properties of different surface morphologies affect the equilibrium structures and substrate-molecules interactions of monolayers, which was achieved through adsorptive analysis methods including adsorptive process, density profile, density distribution and surface potential energy. Analysis on surface potential energy demonstrated that the adsorptivity of amorphous smooth substrate is uniformly distributed over the surface, while DLC substrates with different surface morphologies appear to be more potentially corrugated, which improves the adsorptivity significantly. Because of the large distance of molecules from carbon atoms located at the square groove bottom, substrate-molecules interactions vanish significantly, and thus potassium stearate molecules cannot penetrate completely into the square groove. It can be observed that the equilibrium substrate-molecules interactions of triangle groove and semi-circle groove are much more powerful than that of square groove due to geometrically advantageous properties. These findings provided key information of optimally design of solid substrates with controllable adsorptivity.

Kinetic Transition of Crystal Morphology from Nanoparticles to Dendrites during Electron Beam Induced Deposition of Gold

NASA Astrophysics Data System (ADS)

Park, Jeung Hun; Schneider, Nicholas; Bau, Haim; Kodambaka, Suneel; Ross, Frances

2015-03-01

We studied the kinetic transition from compact nanoparticle to dendritic morphology during electron beam-induced Au deposition using in situ liquid cell-based transmission electron microcopy. Radiolysis of water by electrons generates radicals and molecular species. Hydrated electrons and hydrogen and hydroxide radicals can act as reducing agents and initiate the reduction of the water-soluble precursor, HAuCl4, resulting in the precipitation of Au as nanostructures. We tracked nucleation, growth, and morphological transition of Au from movies recorded in situ, as a function of irradiated dose and liquid thickness. We identified several distinct regimes that depend on the irradiation time: (1) nucleation; (2) linear volumetric growth; (3) formation of dendritic structures; (4) coalescence and dissolution. A diffusion and reaction model for the radiolytic species and metal ions in the confined geometry of the irradiated volume is used to understand the nucleation sites and morphological transitions. We finally describe how nanoparticles can be made to grow in a stepwise manner by switching the supply of Au ions on and off electrochemically, and discuss possibilities for creating more complex nanostructures. This research was partially funded by the National Science Foundation (DMR-1310639, CMMI-1129722, and CBET-1066573).

The effects of engine operating conditions on CCD chemistry and morphology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeh, S.W.; Moore, S.M.; Sabourin, E.T.

1996-10-01

The effects of engine driving cycle and engine coolant temperature on combustion chamber deposit (CCD) surface chemistry and morphology were assessed by the use of XPS and scanning electron micrographs. A 3.1L V6 test cell engine was used to generate a six test matrix that compared deposit surface chemistry and morphology under two distinctly different driving cycles, each cycle being evaluated at three separate engine coolant temperatures. Deposit material for each respective test was collected by removable combustion chamber sample probes that were subjected to XPS surface analysis and SEM evaluation. Discernible trends were observed in surface chemistry and depositmore » amounts with respect to changes in both driving cycle and coolant temperature. However, much more pronounced were deposit morphological changes recorded by SEM in different engine coolant temperature regimes for both of the utilized driving cycles. Deposit nodules formed in one temperature regime were seen to be typically much larger in size, highly irregular in shape, and appeared to be porous in structure. At a different operating temperature, the deposit nodules were observed to be extremely uniform and more tightly packed.« less

The Creation and Statistical Evaluation of a Deterministic Model of the Human Bronchial Tree from HRCT Images.

PubMed

Montesantos, Spyridon; Katz, Ira; Pichelin, Marine; Caillibotte, Georges

2016-01-01

A quantitative description of the morphology of lung structure is essential prior to any form of predictive modeling of ventilation or aerosol deposition implemented within the lung. The human lung is a very complex organ, with airway structures that span two orders of magnitude and having a multitude of interfaces between air, tissue and blood. As such, current medical imaging protocols cannot provide medical practitioners and researchers with in-vivo knowledge of deeper lung structures. In this work a detailed algorithm for the generation of an individualized 3D deterministic model of the conducting part of the human tracheo-bronchial tree is described. Distinct initial conditions were obtained from the high-resolution computed tomography (HRCT) images of seven healthy volunteers. The algorithm developed is fractal in nature and is implemented as a self-similar space sub-division procedure. The expansion process utilizes physiologically realistic relationships and thresholds to produce an anatomically consistent human airway tree. The model was validated through extensive statistical analysis of the results and comparison of the most common morphological features with previously published morphometric studies and other equivalent models. The resulting trees were shown to be in good agreement with published human lung geometric characteristics and can be used to study, among other things, structure-function relationships in simulation studies.

Leg structure explains host site preference in bat flies (Diptera: Streblidae) parasitizing neotropical bats (Chiroptera: Phyllostomidae).

PubMed

Hiller, Thomas; Honner, Benjamin; Page, Rachel A; Tschapka, Marco

2018-03-22

Bat flies (Streblidae) are diverse, obligate blood-feeding insects and probably the most conspicuous ectoparasites of bats. They show preferences for specific body regions on their host bat, which are reflected in behavioural characteristics. In this study, we corroborate the categorization of bat flies into three ecomorphological groups, focusing only on differences in hind leg morphology. As no detailed phylogeny of bat flies is available, it remains uncertain whether these morphological differences reflect the evolutionary history of bat flies or show convergent adaptations for the host habitat type. We show that the division of the host bat into three distinct habitats contributes to the avoidance of interspecific competition of bat fly species. Finally, we found evidence for density-dependent competition between species belonging to the same ecomorphological group.

Bacteria use type IV pili to walk upright and detach from surfaces.

PubMed

Gibiansky, Maxsim L; Conrad, Jacinta C; Jin, Fan; Gordon, Vernita D; Motto, Dominick A; Mathewson, Margie A; Stopka, Wiktor G; Zelasko, Daria C; Shrout, Joshua D; Wong, Gerard C L

2010-10-08

Bacterial biofilms are structured multicellular communities involved in a broad range of infections. Knowing how free-swimming bacteria adapt their motility mechanisms near surfaces is crucial for understanding the transition between planktonic and biofilm phenotypes. By translating microscopy movies into searchable databases of bacterial behavior, we identified fundamental type IV pili-driven mechanisms for Pseudomonas aeruginosa surface motility involved in distinct foraging strategies. Bacteria stood upright and "walked" with trajectories optimized for two-dimensional surface exploration. Vertical orientation facilitated surface detachment and could influence biofilm morphology.

Analysis of the genetic phylogeny of multifocal prostate cancer identifies multiple independent clonal expansions in neoplastic and morphologically normal prostate tissue.

PubMed

Cooper, Colin S; Eeles, Rosalind; Wedge, David C; Van Loo, Peter; Gundem, Gunes; Alexandrov, Ludmil B; Kremeyer, Barbara; Butler, Adam; Lynch, Andrew G; Camacho, Niedzica; Massie, Charlie E; Kay, Jonathan; Luxton, Hayley J; Edwards, Sandra; Kote-Jarai, ZSofia; Dennis, Nening; Merson, Sue; Leongamornlert, Daniel; Zamora, Jorge; Corbishley, Cathy; Thomas, Sarah; Nik-Zainal, Serena; O'Meara, Sarah; Matthews, Lucy; Clark, Jeremy; Hurst, Rachel; Mithen, Richard; Bristow, Robert G; Boutros, Paul C; Fraser, Michael; Cooke, Susanna; Raine, Keiran; Jones, David; Menzies, Andrew; Stebbings, Lucy; Hinton, Jon; Teague, Jon; McLaren, Stuart; Mudie, Laura; Hardy, Claire; Anderson, Elizabeth; Joseph, Olivia; Goody, Victoria; Robinson, Ben; Maddison, Mark; Gamble, Stephen; Greenman, Christopher; Berney, Dan; Hazell, Steven; Livni, Naomi; Fisher, Cyril; Ogden, Christopher; Kumar, Pardeep; Thompson, Alan; Woodhouse, Christopher; Nicol, David; Mayer, Erik; Dudderidge, Tim; Shah, Nimish C; Gnanapragasam, Vincent; Voet, Thierry; Campbell, Peter; Futreal, Andrew; Easton, Douglas; Warren, Anne Y; Foster, Christopher S; Stratton, Michael R; Whitaker, Hayley C; McDermott, Ultan; Brewer, Daniel S; Neal, David E

2015-04-01

Genome-wide DNA sequencing was used to decrypt the phylogeny of multiple samples from distinct areas of cancer and morphologically normal tissue taken from the prostates of three men. Mutations were present at high levels in morphologically normal tissue distant from the cancer, reflecting clonal expansions, and the underlying mutational processes at work in morphologically normal tissue were also at work in cancer. Our observations demonstrate the existence of ongoing abnormal mutational processes, consistent with field effects, underlying carcinogenesis. This mechanism gives rise to extensive branching evolution and cancer clone mixing, as exemplified by the coexistence of multiple cancer lineages harboring distinct ERG fusions within a single cancer nodule. Subsets of mutations were shared either by morphologically normal and malignant tissues or between different ERG lineages, indicating earlier or separate clonal cell expansions. Our observations inform on the origin of multifocal disease and have implications for prostate cancer therapy in individual cases.

The sperm of Hylodinae species (Anura, Leptodactylidae): ultrastructural characteristics and their relevance to interspecific taxonomic relationships.

PubMed

Aguiar, O; Giaretta, A A; Recco-Pimentel, S M

2006-09-01

Hylodinae leptodactylids (sensu Lynch 1971) form a group of diurnal frogs, which is hypothesized on the basis of morphological traits to be the closest relatives of the dendrobatid frogs. Our study describes ultrastructural characteristics of sperm from three hylodine species (Hylodes phyllodes, Crossodactylus sp. n. and Megaelosia massarti) to reassess the intergeneric relationships within the Hylodinae, as well as the supposed relationship between the Hylodinae and Dendrobatidae. The ultrastructure of the sperm is very similar among the three species and is indicative of its conserved nature within the Hylodinae. The structure of the acrosomal complex was very similar to that of other leptodactylid species, to most of the remaining species included in the Bufonoidea lineage, and also to that observed in the dendrobatid species examined so far. Since such a structure has been considered a plesiomorphic trait, it contributes little to our understanding of the relationships between the Hylodinae and Dendrobatidae. The flagellar apparatus of Crossodactylus sp. n. is very similar to that of most leptodactylids. The sperm of Megaelosia massarti and Hylodes phyllodes display a distinctive condition in their axial and juxtaxonemal fibers. This distinctive flagellar condition expands the already known variability in sperm structure within the Leptodactylidae.

Population delimitation across contrasting evolutionary clines in deer mice (Peromyscus maniculatus)

PubMed Central

Yang, D-S; Kenagy, G

2011-01-01

Despite current interest in population genetics, a concrete definition of a “population” remains elusive. Multiple ecologically and evolutionarily based definitions of population are in current use, which focus, respectively, on demographic and genetic interactions. Accurate population delimitation is crucial for not only evolutionary and ecological population biology, but also for conservation of threatened populations. Along the Pacific Coast of North America, two contrasting patterns of geographic variation in deer mice (Peromyscus maniculatus) converge within the state of Oregon. Populations of these mice diverge morphologically across an east–west axis, and they diverge in mitochondrial DNA haplotypes across a north–south axis. In this study, we investigate these geographically contrasting patterns of differentiation in the context of ecological and evolutionary definitions (paradigms) of populations. We investigate these patterns using a new and geographically expansive sample that integrates data on morphology, mitochondrial DNA, and nuclear DNA. We found no evidence of nuclear genetic differentiation between the morphologically and mitochondrially distinct populations, thus indicating the occurrence of gene flow across Oregon. Under the evolutionary paradigm, Oregon populations can be considered a single population, whereas morphological and mitochondrial differentiations do not indicate distinct populations. In contrast, under the ecological paradigm morphological differentiation indicates distinct populations based on the low likelihood of demographic interactions between geographically distant individuals. The two sympatric but mitochondrially distinct haplogroups form a single population under the ecological paradigm. Hence, we find that the difference between evolutionary and ecological paradigms is the time-scale of interest, and we believe that the more chronologically inclusive evolutionary paradigm may be preferable except in cases where only a single generation is of interest. PMID:22393480

The Rock Elm meteorite impact structure, Wisconsin: Geology and shock-metamorphic effects in quartz

USGS Publications Warehouse

French, B.M.; Cordua, W.S.; Plescia, J.B.

2004-01-01

The Rock Elm structure in southwest Wisconsin is an anomalous circular area of highly deformed rocks, ???6.5 km in diameter, located in a region of virtually horizontal undeformed sedimentary rocks. Shock-produced planar microstructures (PMs) have been identified in quartz grains in several lithologies associated with the structure: sandstones, quartzite pebbles, and breccia. Two distinct types of PMs are present: P1 features, which appear identical to planar fractures (PFs or cleavage), and P2 features, which are interpreted as possible incipient planar deformation features (PDFs). The latter are uniquely produced by the shock waves associated with meteorite impact events. Both types of PMs are oriented parallel to specific crystallographic planes in the quartz, most commonly to c(0001), ??112??2, and r/z101??1. The association of unusual, structurally deformed strata with distinct shock-produced microdeformation features in their quartz-bearing rocks establishes Rock Elm as a meteorite impact structure and supports the view that the presence of multiple parallel cleavages in quartz may be used independently as a criterion for meteorite impact. Preliminary paleontological studies indicate a minimum age of Middle Ordovician for the Rock Elm structure. A similar age estimate (450-400 Ma) is obtained independently by combining the results of studies of the general morphology of complex impact structures with estimated rates of sedimentation for the region. Such methods may be applicable to dating other old and deeply eroded impact structures formed in sedimentary target rocks.

Morphology predicts species' functional roles and their degree of specialization in plant-frugivore interactions.

PubMed

Dehling, D Matthias; Jordano, Pedro; Schaefer, H Martin; Böhning-Gaese, Katrin; Schleuning, Matthias

2016-01-27

Species' functional roles in key ecosystem processes such as predation, pollination or seed dispersal are determined by the resource use of consumer species. An interaction between resource and consumer species usually requires trait matching (e.g. a congruence in the morphologies of interaction partners). Species' morphology should therefore determine species' functional roles in ecological processes mediated by mutualistic or antagonistic interactions. We tested this assumption for Neotropical plant-bird mutualisms. We used a new analytical framework that assesses a species's functional role based on the analysis of the traits of its interaction partners in a multidimensional trait space. We employed this framework to test (i) whether there is correspondence between the morphology of bird species and their functional roles and (ii) whether morphologically specialized birds fulfil specialized functional roles. We found that morphological differences between bird species reflected their functional differences: (i) bird species with different morphologies foraged on distinct sets of plant species and (ii) morphologically distinct bird species fulfilled specialized functional roles. These findings encourage further assessments of species' functional roles through the analysis of their interaction partners, and the proposed analytical framework facilitates a wide range of novel analyses for network and community ecology. © 2016 The Author(s).

A new Miocene baleen whale from Peru deciphers the dawn of cetotheriids

PubMed Central

2017-01-01

Cetotheriidae are an iconic, nearly extinct family of baleen whales (Mysticeti) with a highly distinct cranial morphology. Their origins remain a mystery, with even the most archaic species showing a variety of characteristic features. Here, we describe a new species of archaic cetotheriid, Tiucetus rosae, from the Miocene of Peru. The new material represents the first mysticete from the poorly explored lowest portion of the highly fossiliferous Pisco Formation (allomember P0), and appears to form part of a more archaic assemblage than observed at the well-known localities of Cerro Colorado, Cerro los Quesos, Sud-Sacaco and Aguada de Lomas. Tiucetus resembles basal plicogulans (crown Mysticeti excluding right whales), such as Diorocetus and Parietobalaena, but shares with cetotheriids a distinct morphology of the auditory region, including the presence of an enlarged paroccipital concavity. The distinctive morphology of Tiucetus firmly places Cetotheriidae in the context of the poorly understood ‘cetotheres’ sensu lato, and helps to resolve basal relationships within crown Mysticeti. PMID:28989761

A new species of Acanthodactylus Fitzinger 1834 (Sauria: Lacertidae) from southern Iran.

PubMed

Nastaran, Heidari; Nasrullah Rastegar, Pouyani; Eskandar, Rastegar-Pouyani; Mehdi, Rajabizadeh

2013-01-01

A new and distinctive species of lacertid genus Acanthodactylus Fitzinger, 1834 is described from 7 km east of Khamir Port, Hormozgan Province, southern Iran at an elevation of 30-40m above sea level (asl). Analyses of morphological characters and the comparison with other formerly known species of this genus have proven the status of this taxon as a new, distinct species. Combinations of scalation characters and distinct morphology, coloration and habitat peculiarities in calcareous mountains distinguish Acanthodactylus khamirensis sp.nov from all remaining species of the genus in the area. In order to show the validity of the new species, we carried out a comparative statistical analysis using 13 metric and six meristic morphological characters on all of the neighboring congeners of the new species using descriptive (one-way ANOVA) as well as multivariate analyses (PCA and DFA). The results confirm the specific status of the new taxon. Detailed information and an updated identification key for the genus A canthodactylus in Iran are presented.

A new Miocene baleen whale from Peru deciphers the dawn of cetotheriids

NASA Astrophysics Data System (ADS)

Marx, Felix G.; Lambert, Olivier; de Muizon, Christian

2017-09-01

Cetotheriidae are an iconic, nearly extinct family of baleen whales (Mysticeti) with a highly distinct cranial morphology. Their origins remain a mystery, with even the most archaic species showing a variety of characteristic features. Here, we describe a new species of archaic cetotheriid, Tiucetus rosae, from the Miocene of Peru. The new material represents the first mysticete from the poorly explored lowest portion of the highly fossiliferous Pisco Formation (allomember P0), and appears to form part of a more archaic assemblage than observed at the well-known localities of Cerro Colorado, Cerro los Quesos, Sud-Sacaco and Aguada de Lomas. Tiucetus resembles basal plicogulans (crown Mysticeti excluding right whales), such as Diorocetus and Parietobalaena, but shares with cetotheriids a distinct morphology of the auditory region, including the presence of an enlarged paroccipital concavity. The distinctive morphology of Tiucetus firmly places Cetotheriidae in the context of the poorly understood `cetotheres' sensu lato, and helps to resolve basal relationships within crown Mysticeti.

Arcella peruviana sp. nov. (Amoebozoa: Arcellinida, Arcellidae), a new species from a tropical peatland in Amazonia.

PubMed

Reczuga, Monika K; Swindles, Graeme T; Grewling, Łukasz; Lamentowicz, Mariusz

2015-10-01

There has only been one study on the ecology of testate amoebae from Amazonian peatlands, despite Amazonia being a biodiversity hotspot of global importance. During analysis of litter samples from Aucayacu peatland, western (Peruvian) Amazonia, we discovered a testate amoeba with a distinct morphology unlike any other species reported previously. We describe a new species, Arcella peruviana, based on its distinct morphology, compare it to morphologically similar species and provide information about its ecology. This new species is characterised by a distinct cruciform aperture (diameter ranges between 12 and 17μm) which is slightly invaginated. The test is small (height 43-57μm) and polygonal in cross-section. Our discovery suggests the existence of an unknown diversity of testate amoebae in Amazonia. The absence of the new Arcella species in more intensively-sampled regions supports the view that protists have restricted distributions. Copyright © 2015 Elsevier GmbH. All rights reserved.

Comparison of photo- and thermally initiated polymerization-induced self-assembly: a lack of end group fidelity drives the formation of higher order morphologies† †Electronic supplementary information (ESI) available: Additional NMR spectra, SEC, TEM and DLS data as well as histograms for the PEG113–PHPMA400 formulations and MALDI-ToF data for the oligomer study. See DOI: 10.1039/c7py00407a

PubMed Central

Blackman, Lewis D.; Doncom, Kay E. B.

2017-01-01

Polymerization-induced self-assembly (PISA) is an emerging industrially relevant technology, which allows the preparation of defined and predictable polymer self-assemblies with a wide range of morphologies. In recent years, interest has turned to photoinitiated PISA processes, which show markedly accelerated reaction kinetics and milder conditions, thereby making it an attractive alternative to thermally initiated PISA. Herein, we attempt to elucidate the differences between these two initiation methods using isothermally derived phase diagrams of a well-documented poly(ethylene glycol)-b-(2-hydroxypropyl methacrylate) (PEG-b-HPMA) PISA system. By studying the influence of the intensity of the light source used, as well as an investigation into the thermodynamically favorable morphologies, the factors dictating differences in the obtained morphologies when comparing photo- and thermally initiated PISA were explored. Our findings indicate that differences in a combination of both reaction kinetics and end group fidelity led to the observed discrepencies between the two techniques. We find that the loss of the end group in photoinitiated PISA drives the formation of higher order structures and that a morphological transition from worms to unilamellar vesicles could be induced by extended periods of light and heat irradiation. Our findings demonstrate that PISA of identical block copolymers by the two different initiation methods can lead to structures that are both chemically and morphologically distinct. PMID:29225706

Epithelial structure revealed by chemical dissection and unembedded electron microscopy.

PubMed

Fey, E G; Capco, D G; Krochmalnic, G; Penman, S

1984-07-01

Cytoskeletal structures obtained after extraction of Madin-Darby canine kidney epithelial cell monolayers with Triton X-100 were examined in transmission electron micrographs of cell whole mounts and unembedded thick sections. The cytoskeleton, an ordered structure consisting of a peripheral plasma lamina, a complex network of filaments, and chromatin-containing nuclei, was revealed after extraction of intact cells with a nearly physiological buffer containing Triton X-100. The cytoskeleton was further fractionated by extraction with (NH4)2SO4, which left a structure enriched in intermediate filaments and desmosomes around the nuclei. A further digestion with nuclease and elution with (NH4)2SO4 removed the chromatin. The stable structure that remained after this procedure retained much of the epithelial morphology and contained essentially all of the cytokeratin filaments and desmosomes and the chromatin-depleted nuclear matrices. This structural network may serve as a scaffold for epithelial organization. The cytoskeleton and the underlying nuclear matrix intermediate filament scaffold, when examined in both conventional embedded thin sections and in unembedded whole mounts and thick sections, showed the retention of many of the detailed morphological aspects of the intact cells, which suggests a structural continuum linking the nuclear matrix, the intermediate filament network, and the intercellular desmosomal junctions. Most importantly, the protein composition of each of the four fractions obtained by this sequential procedure was essentially unique. Thus, the proteins constituting the soluble fraction, the cytoskeleton, the chromatin fraction, and the underlying nuclear matrix-intermediate filament scaffold are biochemically distinct.

Epithelial structure revealed by chemical dissection and unembedded electron microscopy

PubMed Central

Fey, E. G.; Capco, D. G.; Krochmalnic, G.; Penman, S.

1984-01-01

Cytoskeletal structures obtained after extraction of Madin-Darby canine kidney epithelial cell monolayers with Triton X-100 were examined in transmission electron micrographs of cell whole mounts and unembedded thick sections. The cytoskeleton, an ordered structure consisting of a peripheral plasma lamina, a complex network of filaments, and chromatin-containing nuclei, was revealed after extraction of intact cells with a nearly physiological buffer containing Triton X-100. The cytoskeleton was further fractionated by extraction with (NH4)2SO4, which left a structure enriched in intermediate filaments and desmosomes around the nuclei. A further digestion with nuclease and elution with (NH4)2SO4 removed the chromatin. The stable structure that remained after this procedure retained much of the epithelial morphology and contained essentially all of the cytokeratin filaments and desmosomes and the chromatin-depleted nuclear matrices. This structural network may serve as a scaffold for epithelial organization. The cytoskeleton and the underlying nuclear matrix intermediate filament scaffold, when examined in both conventional embedded thin sections and in unembedded whole mounts and thick sections, showed the retention of many of the detailed morphological aspects of the intact cells, which suggests a structural continuum linking the nuclear matrix, the intermediate filament network, and the intercellular desmosomal junctions. Most importantly, the protein composition of each of the four fractions obtained by this sequential procedure was essentially unique. Thus, the proteins constituting the soluble fraction, the cytoskeleton, the chromatin fraction, and the underlying nuclear matrix-intermediate filament scaffold are biochemically distinct. PMID:6540264

Morphological, structural, and spectral characteristics of amorphous iron sulfates

PubMed Central

Sklute, E. C.; Jensen, H. B.; Rogers, A. D.; Reeder, R. J.

2018-01-01

Current or past brine hydrologic activity on Mars may provide suitable conditions for the formation of amorphous ferric sulfates. Once formed, these phases would likely be stable under current Martian conditions, particularly at low- to mid-latitudes. Therefore, we consider amorphous iron sulfates (AIS) as possible components of Martian surface materials. Laboratory AIS were created through multiple synthesis routes and characterized with total X-ray scattering, thermogravimetric analysis, scanning electron microscopy, visible/near-infrared (VNIR), thermal infrared (TIR), and Mössbauer techniques. We synthesized amorphous ferric sulfates (Fe(III)2(SO4)3 · ~ 6–8H2O) from sulfate-saturated fluids via vacuum dehydration or exposure to low relative humidity (<11%). Amorphous ferrous sulfate (Fe(II)SO4 · ~1H2O) was synthesized via vacuum dehydration of melanterite. All AIS lack structural order beyond 11 Å. The short-range (<5 Å) structural characteristics of amorphous ferric sulfates resemble all crystalline reference compounds; structural characteristics for the amorphous ferrous sulfate are similar to but distinct from both rozenite and szomolnokite. VNIR and TIR spectral data for all AIS display broad, muted features consistent with structural disorder and are spectrally distinct from all crystalline sulfates considered for comparison. Mössbauer spectra are also distinct from crystalline phase spectra available for comparison. AIS should be distinguishable from crystalline sulfates based on the position of their Fe-related absorptions in the visible range and their spectral characteristics in the TIR. In the NIR, bands associated with hydration at ~1.4 and 1.9 μm are significantly broadened, which greatly reduces their detectability in soil mixtures. AIS may contribute to the amorphous fraction of soils measured by the Curiosity rover. PMID:29675340

Influence of Ethnolinguistic Diversity on the Sorghum Genetic Patterns in Subsistence Farming Systems in Eastern Kenya

PubMed Central

Labeyrie, Vanesse; Deu, Monique; Barnaud, Adeline; Calatayud, Caroline; Buiron, Marylène; Wambugu, Peterson; Manel, Stéphanie; Glaszmann, Jean-Christophe; Leclerc, Christian

2014-01-01

Understanding the effects of actions undertaken by human societies on crop evolution processes is a major challenge for the conservation of genetic resources. This study investigated the mechanisms whereby social boundaries associated with patterns of ethnolinguistic diversity have influenced the on-farm distribution of sorghum diversity. Social boundaries limit the diffusion of planting material, practices and knowledge, thus shaping crop diversity in situ. To assess the effect of social boundaries, this study was conducted in the contact zone between the Chuka, Mbeere and Tharaka ethnolinguistic groups in eastern Kenya. Sorghum varieties were inventoried and samples collected in 130 households. In all, 297 individual plants derived from seeds collected under sixteen variety names were characterized using a set of 18 SSR molecular markers and 15 morphological descriptors. The genetic structure was investigated using both a Bayesian assignment method and distance-based clustering. Principal Coordinates Analysis was used to describe the structure of the morphological diversity of the panicles. The distribution of the varieties and the main genetic clusters across ethnolinguistic groups was described using a non-parametric MANOVA and pairwise Fisher tests. The spatial distribution of landrace names and the overall genetic spatial patterns were significantly correlated with ethnolinguistic partition. However, the genetic structure inferred from molecular makers did not discriminate the short-cycle landraces despite their morphological distinctness. The cases of two improved varieties highlighted possible fates of improved materials. The most recent one was often given the name of local landraces. The second one, that was introduced a dozen years ago, displays traces of admixture with local landraces with differential intensity among ethnic groups. The patterns of congruence or discordance between the nomenclature of farmers’ varieties and the structure of both genetic and morphological diversity highlight the effects of the social organization of communities on the diffusion of seed, practices, and variety nomenclature. PMID:24637745

Multiscale Feature Analysis of Salivary Gland Branching Morphogenesis

PubMed Central

Baydil, Banu; Daley, William P.; Larsen, Melinda; Yener, Bülent

2012-01-01

Pattern formation in developing tissues involves dynamic spatio-temporal changes in cellular organization and subsequent evolution of functional adult structures. Branching morphogenesis is a developmental mechanism by which patterns are generated in many developing organs, which is controlled by underlying molecular pathways. Understanding the relationship between molecular signaling, cellular behavior and resulting morphological change requires quantification and categorization of the cellular behavior. In this study, tissue-level and cellular changes in developing salivary gland in response to disruption of ROCK-mediated signaling by are modeled by building cell-graphs to compute mathematical features capturing structural properties at multiple scales. These features were used to generate multiscale cell-graph signatures of untreated and ROCK signaling disrupted salivary gland organ explants. From confocal images of mouse submandibular salivary gland organ explants in which epithelial and mesenchymal nuclei were marked, a multiscale feature set capturing global structural properties, local structural properties, spectral, and morphological properties of the tissues was derived. Six feature selection algorithms and multiway modeling of the data was performed to identify distinct subsets of cell graph features that can uniquely classify and differentiate between different cell populations. Multiscale cell-graph analysis was most effective in classification of the tissue state. Cellular and tissue organization, as defined by a multiscale subset of cell-graph features, are both quantitatively distinct in epithelial and mesenchymal cell types both in the presence and absence of ROCK inhibitors. Whereas tensor analysis demonstrate that epithelial tissue was affected the most by inhibition of ROCK signaling, significant multiscale changes in mesenchymal tissue organization were identified with this analysis that were not identified in previous biological studies. We here show how to define and calculate a multiscale feature set as an effective computational approach to identify and quantify changes at multiple biological scales and to distinguish between different states in developing tissues. PMID:22403724

A statistical approach to root system classification

PubMed Central

Bodner, Gernot; Leitner, Daniel; Nakhforoosh, Alireza; Sobotik, Monika; Moder, Karl; Kaul, Hans-Peter

2013-01-01

Plant root systems have a key role in ecology and agronomy. In spite of fast increase in root studies, still there is no classification that allows distinguishing among distinctive characteristics within the diversity of rooting strategies. Our hypothesis is that a multivariate approach for “plant functional type” identification in ecology can be applied to the classification of root systems. The classification method presented is based on a data-defined statistical procedure without a priori decision on the classifiers. The study demonstrates that principal component based rooting types provide efficient and meaningful multi-trait classifiers. The classification method is exemplified with simulated root architectures and morphological field data. Simulated root architectures showed that morphological attributes with spatial distribution parameters capture most distinctive features within root system diversity. While developmental type (tap vs. shoot-borne systems) is a strong, but coarse classifier, topological traits provide the most detailed differentiation among distinctive groups. Adequacy of commonly available morphologic traits for classification is supported by field data. Rooting types emerging from measured data, mainly distinguished by diameter/weight and density dominated types. Similarity of root systems within distinctive groups was the joint result of phylogenetic relation and environmental as well as human selection pressure. We concluded that the data-define classification is appropriate for integration of knowledge obtained with different root measurement methods and at various scales. Currently root morphology is the most promising basis for classification due to widely used common measurement protocols. To capture details of root diversity efforts in architectural measurement techniques are essential. PMID:23914200

A statistical approach to root system classification.

PubMed

Bodner, Gernot; Leitner, Daniel; Nakhforoosh, Alireza; Sobotik, Monika; Moder, Karl; Kaul, Hans-Peter

2013-01-01

Plant root systems have a key role in ecology and agronomy. In spite of fast increase in root studies, still there is no classification that allows distinguishing among distinctive characteristics within the diversity of rooting strategies. Our hypothesis is that a multivariate approach for "plant functional type" identification in ecology can be applied to the classification of root systems. The classification method presented is based on a data-defined statistical procedure without a priori decision on the classifiers. The study demonstrates that principal component based rooting types provide efficient and meaningful multi-trait classifiers. The classification method is exemplified with simulated root architectures and morphological field data. Simulated root architectures showed that morphological attributes with spatial distribution parameters capture most distinctive features within root system diversity. While developmental type (tap vs. shoot-borne systems) is a strong, but coarse classifier, topological traits provide the most detailed differentiation among distinctive groups. Adequacy of commonly available morphologic traits for classification is supported by field data. Rooting types emerging from measured data, mainly distinguished by diameter/weight and density dominated types. Similarity of root systems within distinctive groups was the joint result of phylogenetic relation and environmental as well as human selection pressure. We concluded that the data-define classification is appropriate for integration of knowledge obtained with different root measurement methods and at various scales. Currently root morphology is the most promising basis for classification due to widely used common measurement protocols. To capture details of root diversity efforts in architectural measurement techniques are essential.

Schizophrenia and the structure of language: the linguist's view.

PubMed

Covington, Michael A; He, Congzhou; Brown, Cati; Naçi, Lorina; McClain, Jonathan T; Fjordbak, Bess Sirmon; Semple, James; Brown, John

2005-09-01

Patients with schizophrenia often display unusual language impairments. This is a wide ranging critical review of the literature on language in schizophrenia since the 19th century. We survey schizophrenic language level by level, from phonetics through phonology, morphology, syntax, semantics, and pragmatics. There are at least two kinds of impairment (perhaps not fully distinct): thought disorder, or failure to maintain a discourse plan, and schizophasia, comprising various dysphasia-like impairments such as clanging, neologism, and unintelligible utterances. Thought disorder appears to be primarily a disruption of executive function and pragmatics, perhaps with impairment of the syntax-semantics interface; schizophasia involves disruption at other levels. Phonetics is also often abnormal (manifesting as flat intonation or unusual voice quality), but phonological structure, morphology, and syntax are normal or nearly so (some syntactic impairments have been demonstrated). Access to the lexicon is clearly impaired, manifesting as stilted speech, word approximation, and neologism. Clanging (glossomania) is straightforwardly explainable as distraction by self-monitoring. Recent research has begun to relate schizophrenia, which is partly genetic, to the genetic endowment that makes human language possible.

Chemical synthesis and structural characterization of small AuZn nanoparticles

NASA Astrophysics Data System (ADS)

Juárez-Ruiz, E.; Pal, U.; Lombardero-Chartuni, J. A.; Medina, A.; Ascencio, J. A.

2007-03-01

In this paper, we report the aqueous synthesis of bimetallic Au-Zn nanoparticles of different compositions by the simultaneous reduction technique. The stability and atomic configuration of the particles are studied through high-resolution transmission electron microscopy (HRTEM) and UV-Vis optical absorption techniques. Depending on the composition, small bimetallic nanoparticles of 1 15 nm in size were obtained. The average size and size distribution of the bimetallic nanoparticles are seen to be critically dependent on the atomic ratio of the constituting elements Au and Zn. While a 1:1 atomic proportion of Au and Zn produced most stable nanoparticles of smallest average size, nanoparticles produced with higher content of either of the component elements are unstable, inducing agglomeration and coalescence to form elongated structures with uneven morphologies. Au3Zn1 nanoparticles followed a directional growth pattern, producing bimetallic nanorods with multiple crystalline domains. Interestingly, in these rod-like nanostructures, the domains are in well array of solid solution-like bimetallic and pure mono-metallic regions alternatively. Such nanostructures with uneven morphology and compositions might show distinct catalytic selectivity in chemical reactions.

A clathrin coat assembly role for the muniscin protein central linker revealed by TALEN-mediated gene editing

PubMed Central

Umasankar, Perunthottathu K; Ma, Li; Thieman, James R; Jha, Anupma; Doray, Balraj; Watkins, Simon C; Traub, Linton M

2014-01-01

Clathrin-mediated endocytosis is an evolutionarily ancient membrane transport system regulating cellular receptivity and responsiveness. Plasmalemma clathrin-coated structures range from unitary domed assemblies to expansive planar constructions with internal or flanking invaginated buds. Precisely how these morphologically-distinct coats are formed, and whether all are functionally equivalent for selective cargo internalization is still disputed. We have disrupted the genes encoding a set of early arriving clathrin-coat constituents, FCHO1 and FCHO2, in HeLa cells. Endocytic coats do not disappear in this genetic background; rather clustered planar lattices predominate and endocytosis slows, but does not cease. The central linker of FCHO proteins acts as an allosteric regulator of the prime endocytic adaptor, AP-2. By loading AP-2 onto the plasma membrane, FCHO proteins provide a parallel pathway for AP-2 activation and clathrin-coat fabrication. Further, the steady-state morphology of clathrin-coated structures appears to be a manifestation of the availability of the muniscin linker during lattice polymerization. DOI: http://dx.doi.org/10.7554/eLife.04137.001 PMID:25303365

Morphology Control of Carbon-Free Spinel NiCo 2 O 4 Catalysts for Enhanced Bifunctional Oxygen Reduction and Evolution in Alkaline Media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Devaguptapu, Surya V.; Hwang, Sooyeon; Karakalos, Stavros

Spinel NiCo 2O 4 is considered a promising precious metal-free catalyst that is also carbon-free for oxygen electrocatalysis. Current efforts mainly focus on optimal chemical doping and substituent to tune its electronic structures for enhanced activity. Here, we study its morphology control and elucidate the morphology-dependent catalyst performance for bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Three types of NiCo 2O 4 catalysts with significantly distinct morphologies were prepared using temple-free, Pluronic-123 (P-123) soft, and SiO 2 hard templates, respectively, via hydrothermal methods following by a calcination. While the hard-template yields sphere-like dense structures, soft-template assists themore » formation of a unique nano-needle cluster assembly containing abundant meso- and macro pores. Furthermore, the effect of morphology of NiCo 2O 4 on their corresponding bifunctional catalytic performance was systematically investigated. The flower-like nano-needle assembly NiCo 2O 4 catalyst via the soft template method exhibited the highest catalytic activity and stability for both ORR and OER. In particular, it exhibited an onset and half-wave potentials of 0.94 and 0.82 V vs. RHE, respectively, for the ORR in alkaline media. Although it is still inferior to Pt, the NiCo 2O 4 represents one of the best ORR catalyst compared to other reported carbon-free oxides. Meanwhile, remarkable OER activity and stability were achieved with an onset potential of 1.48 V and a current density of 15 mA/cm 2 at 1.6 V, showing no activity loss after 20,000 potential cycles (0 to 1.9 V). The demonstrated stability is even superior to Ir for the OER. The morphology-controlled approach provides an effective solution to create a robust 3D architecture with increased surface areas and enhanced mass transfer. More importantly, the soft template can yield high degree of spinel crystallinity with ideal stoichiometric ratios between Ni and Co, thus promoting structural integrity with enhanced electrical conductivity and catalytic properties.« less

Morphology Control of Carbon-Free Spinel NiCo 2 O 4 Catalysts for Enhanced Bifunctional Oxygen Reduction and Evolution in Alkaline Media

DOE PAGES

Devaguptapu, Surya V.; Hwang, Sooyeon; Karakalos, Stavros; ...

2017-12-06

Spinel NiCo 2O 4 is considered a promising precious metal-free catalyst that is also carbon-free for oxygen electrocatalysis. Current efforts mainly focus on optimal chemical doping and substituent to tune its electronic structures for enhanced activity. Here, we study its morphology control and elucidate the morphology-dependent catalyst performance for bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Three types of NiCo 2O 4 catalysts with significantly distinct morphologies were prepared using temple-free, Pluronic-123 (P-123) soft, and SiO 2 hard templates, respectively, via hydrothermal methods following by a calcination. While the hard-template yields sphere-like dense structures, soft-template assists themore » formation of a unique nano-needle cluster assembly containing abundant meso- and macro pores. Furthermore, the effect of morphology of NiCo 2O 4 on their corresponding bifunctional catalytic performance was systematically investigated. The flower-like nano-needle assembly NiCo 2O 4 catalyst via the soft template method exhibited the highest catalytic activity and stability for both ORR and OER. In particular, it exhibited an onset and half-wave potentials of 0.94 and 0.82 V vs. RHE, respectively, for the ORR in alkaline media. Although it is still inferior to Pt, the NiCo 2O 4 represents one of the best ORR catalyst compared to other reported carbon-free oxides. Meanwhile, remarkable OER activity and stability were achieved with an onset potential of 1.48 V and a current density of 15 mA/cm 2 at 1.6 V, showing no activity loss after 20,000 potential cycles (0 to 1.9 V). The demonstrated stability is even superior to Ir for the OER. The morphology-controlled approach provides an effective solution to create a robust 3D architecture with increased surface areas and enhanced mass transfer. More importantly, the soft template can yield high degree of spinel crystallinity with ideal stoichiometric ratios between Ni and Co, thus promoting structural integrity with enhanced electrical conductivity and catalytic properties.« less

Comparison of morphological and genetic analyses reveals cryptic divergence and morphological plasticity in Stylophora (Cnidaria, Scleractinia)

NASA Astrophysics Data System (ADS)

Stefani, Fabrizio; Benzoni, F.; Yang, S.-Y.; Pichon, M.; Galli, P.; Chen, C. A.

2011-12-01

A combined morphological and genetic study of the coral genus Stylophora investigated species boundaries in the Gulf of Aden, Yemen. Two mitochondrial regions, including the hypervariable IGS9 spacer and the control region, and a fragment of rDNA were used for phylogenetic analysis. Results were compared by multivariate analysis on the basis of branch morphology and corallite morphometry. Two species were clearly discriminated by both approaches. The first species was characterised by small corallites and a low morphological variability and was ascribed to a new geographical record of Stylophora madagascarensis on the basis of its phylogenetic distinction and its morphological similarity to the type material. The second species was characterised by larger corallite size and greater morphological variability and was ascribed to Stylophora pistillata. The analysis was extended to the intrageneric level for other S. pistillata populations from the Red Sea and the Pacific Ocean. Strong internal divergence was evident in the genus Sty lophora. S. pistillata populations were split into two highly divergent Red Sea/Gulf of Aden and western Pacific lineages with significant morphological overlap, which suggests they represent two distinct cryptic species. The combined use of morphological and molecular approaches, so far proved to be a powerful tool for the re-delineation of species boundaries in corals, provided novel evidence of cryptic divergence in this group of marine metazoans.

Characterization of cell surface and extracellular matrix remodeling of Azospirillum brasilense chemotaxis-like 1 signal transduction pathway mutants by atomic force microscopy.

PubMed

Edwards, Amanda Nicole; Siuti, Piro; Bible, Amber N; Alexandre, Gladys; Retterer, Scott T; Doktycz, Mitchel J; Morrell-Falvey, Jennifer L

2011-01-01

To compete in complex microbial communities, bacteria must sense environmental changes and adjust cellular functions for optimal growth. Chemotaxis-like signal transduction pathways are implicated in the regulation of multiple behaviors in response to changes in the environment, including motility patterns, exopolysaccharide production, and cell-to-cell interactions. In Azospirillum brasilense, cell surface properties, including exopolysaccharide production, are thought to play a direct role in promoting flocculation. Recently, the Che1 chemotaxis-like pathway from A. brasilense was shown to modulate flocculation, suggesting an associated modulation of cell surface properties. Using atomic force microscopy, distinct changes in the surface morphology of flocculating A. brasilense Che1 mutant strains were detected. Whereas the wild-type strain produces a smooth mucosal extracellular matrix after 24 h, the flocculating Che1 mutant strains produce distinctive extracellular fibril structures. Further analyses using flocculation inhibition, lectin-binding assays, and comparison of lipopolysaccharides profiles suggest that the extracellular matrix differs between the cheA1 and the cheY1 mutants, despite an apparent similarity in the macroscopic floc structures. Collectively, these data indicate that disruption of the Che1 pathway is correlated with distinctive changes in the extracellular matrix, which likely result from changes in surface polysaccharides structure and/or composition. FEMS Microbiology Letters © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. No claim to original US government works.

Phylogeography, phylogeny and hybridization in trichechid sirenians: Implications for manatee conservation

USGS Publications Warehouse

Vianna, J.A.; Bonde, R.K.; Caballero, S.; Giraldo, J.P.; Lima, R.P.; Clark, A.; Marmontel, M.; Morales-Vela, B.; De Souza, M. J.; Parr, L.; Rodriguez-Lopez, M.A.; Mignucci-Giannoni, A. A.; Powell, J.A.; Santos, F.R.

2006-01-01

The three living species of manatees, West Indian (Trichechus manatus), Amazonian (Trichechus inunguis) and West African (Trichechus senegalensis), are distributed across the shallow tropical and subtropical waters of America and the western coast of Africa. We have sequenced the mitochondrial DNA control region in 330 Trichechus to compare their phylogeographic patterns. In T. manatus we observed a marked population structure with the identification of three haplotype clusters showing a distinct spatial distribution. A geographic barrier represented by the continuity of the Lesser Antilles to Trinidad Island, near the mouth of the Orinoco River in Venezuela, appears to have restricted the gene flow historically in T. manatus. However, for T. inunguis we observed a single expanding population cluster, with a high diversity of very closely related haplotypes. A marked geographic population structure is likely present in T. senegalensis with at least two distinct clusters. Phylogenetic analyses with the mtDNA cytochrome b gene suggest a clade of the marine Trichechus species, with T. inunguis as the most basal trichechid. This is in agreement with previous morphological analyses. Mitochondrial DNA, autosomal microsatellites and cytogenetic analyses revealed the presence of hybrids between the T. manatus and T. inunguis species at the mouth of the Amazon River in Brazil, extending to the Guyanas and probably as far as the mouth of the Orinoco River. Future conservation strategies should consider the distinct population structure of manatee species, as well as the historical barriers to gene flow and the likely occurrence of interspecific hybridization. ?? 2006 Blackwell Publishing Ltd.

The Cultural Evolution of Structured Languages in an Open-Ended, Continuous World.

PubMed

Carr, Jon W; Smith, Kenny; Cornish, Hannah; Kirby, Simon

2017-05-01

Language maps signals onto meanings through the use of two distinct types of structure. First, the space of meanings is discretized into categories that are shared by all users of the language. Second, the signals employed by the language are compositional: The meaning of the whole is a function of its parts and the way in which those parts are combined. In three iterated learning experiments using a vast, continuous, open-ended meaning space, we explore the conditions under which both structured categories and structured signals emerge ex nihilo. While previous experiments have been limited to either categorical structure in meanings or compositional structure in signals, these experiments demonstrate that when the meaning space lacks clear preexisting boundaries, more subtle morphological structure that lacks straightforward compositionality-as found in natural languages-may evolve as a solution to joint pressures from learning and communication. Copyright © 2016 The Authors. Cognitive Science published by Wiley Periodicals, Inc. on behalf of Cognitive Science Society.

Distinct C9orf72-Associated Dipeptide Repeat Structures Correlate with Neuronal Toxicity

PubMed Central

Krans, Amy; Sawaya, Michael R.; Paulson, Henry L.; Todd, Peter K.; Barmada, Sami J.; Ivanova, Magdalena I.

2016-01-01

Hexanucleotide repeat expansions in C9orf72 are the most common inherited cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The expansions elicit toxicity in part through repeat-associated non-AUG (RAN) translation of the intronic (GGGGCC)n sequence into dipeptide repeat-containing proteins (DPRs). Little is known, however, about the structural characteristics and aggregation propensities of the dipeptide units comprising DPRs. To address this question, we synthesized dipeptide units corresponding to the three sense-strand RAN translation products, analyzed their structures by circular dichroism, electron microscopy and dye binding assays, and assessed their relative toxicity when applied to primary cortical neurons. Short, glycine-arginine (GR)3 dipeptides formed spherical aggregates and selectively reduced neuronal survival compared to glycine-alanine (GA)3 and glycine-proline (GP)3 dipeptides. Doubling peptide length had little effect on the structure of GR or GP peptides, but (GA)6 peptides formed β-sheet rich aggregates that bound thioflavin T and Congo red yet lacked the typical fibrillar morphology of amyloids. Aging of (GA)6 dipeptides increased their β-sheet content and enhanced their toxicity when applied to neurons. We also observed that the relative toxicity of each tested dipeptide was proportional to peptide internalization. Our results demonstrate that different C9orf72-related dipeptides exhibit distinct structural properties that correlate with their relative toxicity. PMID:27776165

Foraging and ranging behavior during a fallback episode: Hylobates albibarbis and Pongo pygmaeus wurmbii compared.

PubMed

Vogel, Erin R; Haag, Livia; Mitra-Setia, Tatang; van Schaik, Carel P; Dominy, Nathaniel J

2009-12-01

Periodic episodes of food scarcity may highlight the adaptive value of certain anatomical traits, particularly those that facilitate the acquisition and digestion of exigent fallback foods. To better understand the selective pressures that favored the distinctive dental and locomotor morphologies of gibbons and orangutans, we examined the foraging and ranging behavior of sympatric Hylobates albibarbis and Pongo pygmaeus wurmbii during an episode of low fruit availability at Tuanan, Kalimantan Tengah, Indonesia. We found that Hylobates ranged 0.5 km day(-1) or 33% farther than did Pongo, but the overall daily ranging of both species did not vary as fruit availability decreased by as much as 50%. Among gibbons, we observed dietary switching to fallback foods; in particular, there was a progressively greater reliance on figs, liana products, and unripe fruit. Orangutans relied heavily on unripe fruit and fracture-resistant bark and pith tissues. Despite these divergent fallback patterns, the stiffness of fruit mesocarp consumed by Hylobates and Pongo did not differ. We discuss canine and molar functional morphology with respect to dietary mechanics. Next, to contextualize these results, we discuss our findings with respect to forest structure. The rain forests of Southeast Asia have been described as having open, discontinuous canopies. Such a structure may inform our understanding of the ranging behavior and distinctive locomotion of apes in the region, namely richochetal brachiation and quadrumanous clambering. Our approach of integrating behavioral ecology with physical measures of food may be a powerful tool for understanding the functional adaptations of primates.

Isometric immersions and self-similar buckling in elastic sheets.

NASA Astrophysics Data System (ADS)

Gemmer, John

The edges of torn elastic sheets and growing leaves often display hierarchical self-similar like buckling patterns. On the one hand, such complex, self similar patterns are usually associated with a competition between two distinct energy scales, e.g. elastic sheets with boundary conditions that preclude the possibility of relieving in plane strains, or at alloy-alloy interfaces between distinct crystal structures. On the other hand, within the non-Euclidean plate theory this complex morphology can be understood as low bending energy isometric immersions of hyperbolic Riemannian metrics. In particular, many growth patterns generate residual in-plane strains which can be entirely relieved by the sheet forming part of a surface of revolution or a helix. In this talk we will show that this complex morphology (i) arises from isometric immersions (ii) is driven by a competition between the two principal curvatures, rather than between bending and stretching. We identify the key role of branch-point (or monkey-saddle) singularities, in complex wrinkling patterns within the class of finite bending energy isometric immersions. Using these defects we will give an explicit construction of strain-free embeddings of hyperbolic surfaces that are fractal like and have lower elastic energy than their smooth counterparts US-Israel BSF Grant 2008432. NSF Grant DMS-0807501. NSF-RTG Grant DMS-1148284.

Collapsed state of polyglutamic acid results in amyloid spherulite formation

PubMed Central

Stehli, Daniel; Mulaj, Mentor; Miti, Tatiana; Traina, Joshua; Foley, Joseph; Muschol, Martin

2015-01-01

Self-assembly of proteins and peptides into amyloid fibrils involves multiple distinct intermediates and late-stage fibrillar polymorphs. Understanding the conditions and mechanisms that promote the formation of one type of intermediate and polymorph over the other represents a fundamental challenge. Answers to this question are also of immediate biomedical relevance since different amyloid aggregate species have been shown to have distinct pathogenic potencies. One amyloid polymorph that has received comparatively little attention are amyloid spherulites. Here we report that self-assembly of the intrinsically disordered polymer poly(L-glutamic) acid (PLE) can generate amyloid spherulites. We characterize spherulite growth kinetics, as well as the morphological, optical and tinctorial features of this amyloid polymorph previously unreported for PLE. We find that PLE spherulites share both tinctorial and structural characteristics with their amyloid fibril counterparts. Differences in PLE's molecular weight, polydispersity or chemistry could not explain the selective propensity toward either fibril or spherulite formation. Instead, we provide evidence that PLE polymers can exist in either a collapsed globule or an extended random coil conformation. The collapsed globule consistently produces spherulites while the extended coil assembles into disordered fibril bundles. This results suggests that these 2 PLE conformers directly affect the morphology of the resulting macroscopic amyloid assembly. PMID:28232889

Collapsed state of polyglutamic acid results in amyloid spherulite formation.

PubMed

Stehli, Daniel; Mulaj, Mentor; Miti, Tatiana; Traina, Joshua; Foley, Joseph; Muschol, Martin

2015-01-01

Self-assembly of proteins and peptides into amyloid fibrils involves multiple distinct intermediates and late-stage fibrillar polymorphs. Understanding the conditions and mechanisms that promote the formation of one type of intermediate and polymorph over the other represents a fundamental challenge. Answers to this question are also of immediate biomedical relevance since different amyloid aggregate species have been shown to have distinct pathogenic potencies. One amyloid polymorph that has received comparatively little attention are amyloid spherulites. Here we report that self-assembly of the intrinsically disordered polymer poly(L-glutamic) acid (PLE) can generate amyloid spherulites. We characterize spherulite growth kinetics, as well as the morphological, optical and tinctorial features of this amyloid polymorph previously unreported for PLE. We find that PLE spherulites share both tinctorial and structural characteristics with their amyloid fibril counterparts. Differences in PLE's molecular weight, polydispersity or chemistry could not explain the selective propensity toward either fibril or spherulite formation. Instead, we provide evidence that PLE polymers can exist in either a collapsed globule or an extended random coil conformation. The collapsed globule consistently produces spherulites while the extended coil assembles into disordered fibril bundles. This results suggests that these 2 PLE conformers directly affect the morphology of the resulting macroscopic amyloid assembly.

Enhanced magnetization in morphologically and magnetically distinct BiFeO3 and La0.7Sr0.3MnO3 composites

NASA Astrophysics Data System (ADS)

Pillai, Shreeja; Reshi, Hilal Ahmad; Bagwaiya, Toshi; Banerjee, Alok; Shelke, Vilas

2017-09-01

Nanomaterials exhibit properties different from those of their bulk counterparts. The modified magnetic characteristics of manganite nanoparticles were exploited to improve magnetization in multiferroic BiFeO3 compound. We studied the composite of two morphologically and magnetically distinct compounds BiFeO3 (BFO) and La0.7Sr0.3MnO3 (LSMO). The microcrystalline BiFeO3 sample was prepared by solid state reaction method and the nanocrystalline La0.7Sr0.3MnO3 by sol-gel method. Composites with nominal compositions (1-x)BiFeO3-(x)La0.7Sr0.3MnO3 were prepared by modified solid state reaction method. The phase purity and crystal structures were checked by using X-ray diffraction. The formation of composites with phase separated BFO and LSMO was confirmed using Raman and Fourier Transform Infrared spectroscopy studies. The composite samples showed relatively high value of magnetization with finite coercivity. This improvement in magnetic behavior is ascribed to the coexistence of multiple magnetic orderings in composite samples. We scrutinized the possibility of oxygen vacancy or Fe mixed valency formation in the samples using X-ray photoelectron spectroscopy technique.

Defect-mediated phonon dynamics in TaS2 and WSe2

PubMed Central

Cremons, Daniel R.; Plemmons, Dayne A.; Flannigan, David J.

2017-01-01

We report correlative crystallographic and morphological studies of defect-dependent phonon dynamics in single flakes of 1T-TaS2 and 2H-WSe2 using selected-area diffraction and bright-field imaging in an ultrafast electron microscope. In both materials, we observe in-plane speed-of-sound acoustic-phonon wave trains, the dynamics of which (i.e., emergence, propagation, and interference) are strongly dependent upon discrete interfacial features (e.g., vacuum/crystal and crystal/crystal interfaces). In TaS2, we observe cross-propagating in-plane acoustic-phonon wave trains of differing frequencies that undergo coherent interference approximately 200 ps after initial emergence from distinct interfacial regions. With ultrafast bright-field imaging, the properties of the interfering wave trains are observed to correspond to the beat frequency of the individual oscillations, while intensity oscillations of Bragg spots generated from selected areas within the region of interest match well with the real-space dynamics. In WSe2, distinct acoustic-phonon dynamics are observed emanating and propagating away from structurally dissimilar morphological discontinuities (vacuum/crystal interface and crystal terrace), and results of ultrafast selected-area diffraction reveal thickness-dependent phonon frequencies. The overall observed dynamics are well-described using finite element analysis and time-dependent linear-elastic continuum mechanics. PMID:28503630

Description of a new species of crested newt, previously subsumed in Triturus ivanbureschi (Amphibia: Caudata: Salamandridae).

PubMed

Wielstra, B; Arntzen, J W

2016-05-05

Multilocus molecular data play a pivotal role in diagnosing cryptic species (i.e. genetically distinct but morphologically similar species). A multilocus phylogeographic survey has provided compelling evidence that Triturus ivanbureschi sensu lato comprises two distinct gene pools with restricted gene flow. We conclude that this taxon had better be treated as two distinct (albeit morphologically cryptic) species. The name T. ivanbureschi should be restricted to the western species, which is distributed in western Asiatic Turkey plus the south-eastern Balkan Peninsula. No name is as yet available for the eastern species, which is distributed in northern Asiatic Turkey. We propose the name T. anatolicus sp. nov. for the eastern species and provide a formal species description.

Importance of MAP Kinases during Protoperithecial Morphogenesis in Neurospora crassa

PubMed Central

Jeffree, Chris E.; Oborny, Radek; Boonyarungsrit, Patid; Read, Nick D.

2012-01-01

In order to produce multicellular structures filamentous fungi combine various morphogenetic programs that are fundamentally different from those used by plants and animals. The perithecium, the female sexual fruitbody of Neurospora crassa, differentiates from the vegetative mycelium in distinct morphological stages, and represents one of the more complex multicellular structures produced by fungi. In this study we defined the stages of protoperithecial morphogenesis in the N. crassa wild type in greater detail than has previously been described; compared protoperithecial morphogenesis in gene-deletion mutants of all nine mitogen-activated protein (MAP) kinases conserved in N. crassa; confirmed that all three MAP kinase cascades are required for sexual development; and showed that the three different cascades each have distinctly different functions during this process. However, only MAP kinases equivalent to the budding yeast pheromone response and cell wall integrity pathways, but not the osmoregulatory pathway, were essential for vegetative cell fusion. Evidence was obtained for MAP kinase signaling cascades performing roles in extracellular matrix deposition, hyphal adhesion, and envelopment during the construction of fertilizable protoperithecia. PMID:22900028

Oxygen K edge scattering from bulk comb diblock copolymer reveals extended, ordered backbones above lamellar order-disorder transition

DOE PAGES

Kortright, Jeffrey Barrett; Sun, Jing; Spencer, Ryan K.; ...

2016-12-14

The evolution of molecular morphology in bulk samples of comb diblock copolymer pNdc 12-b-pNte 21 across the lamellar order-disorder transition (ODT) is studied using resonant x-ray scattering at the oxygen K edge, with the goal of determining whether the molecules remain extended or collapse above the ODT. The distinct spectral resonances of carbonyl oxygen on the backbone and ether oxygen in the pNte side chains combine with their different site symmetry within the molecule to yield strong differences in bulk structural sensitivity at all temperatures. Comparison with simple models for the disordered phase clearly reveals that disordering at the ODTmore » corresponds to loss of positional order of molecules with extended backbones that retain orientational order, rather than backbone collapse into a locally isotropic disordered phase. This conclusion is facilitated directly by the distinct structural sensitivity at the two resonances. Lastly, we discuss the roles of depolarized scattering in enhancing this sensitivity, and background fluorescence in limiting dynamic range, in oxygen resonant scattering.« less

Macrochaete gen. nov. (Nostocales, Cyanobacteria), a taxon morphologically and molecularly distinct from Calothrix.

PubMed

Berrendero Gómez, Esther; Johansen, Jeffrey R; Kaštovský, Jan; Bohunická, Markéta; Čapková, Kateřina

2016-08-01

Historically, the genus Calothrix included all noncolonial, tapered, heterocytous filaments within the cyanobacteria. However, recent molecular phylogenies show that "Calothrix" defined in this sense represents five distinct clades. The type species of Calothrix is marine, with solitary basal heterocytes, no akinetes, and distal ends tapering abruptly into short hairs. We examined the morphology and phylogeny of 45 tapering cyanobacteria in the Rivulariaceae, including freshwater and marine representatives of both Calothrix (35 strains) and its sister taxon Rivularia (10 strains). The marine Calothrix fall into two lineages, but we lack the generitype and so cannot identify the clade corresponding to the type species. The freshwater and soil Calothrix fall into the C. parietina clade and are characterized by having a basal heterocyte, no akinetes, and gradual tapering-but not into a long hyaline hair. Macrochaete gen. nov. is a freshwater taxon sister to the Calothrix lineages but clearly separated from Rivularia. The species in this genus differ morphologically from Calothrix by their ability to produce two heteromorphic basal heterocytes and specific secondary structures of the 16S-23S ITS. An additional feature present in most species is the presence of a distal, long hyaline hair, but this character has incomplete penetrance due to its expression only under specific environmental conditions (low phosphate), and in one species appears to be lost. We recognize three species: M. psychrophila (type species) from cold environments (high mountains, Antarctica), M. santannae from wet walls of subtropical South America, and M. lichenoides, a phycobiont of lichens from Europe. © 2016 Phycological Society of America.

Morphology of ejected particles and impact sites on intercepting substrates following exit-surface laser damage with nanosecond pulses in silica

DOE PAGES

Demos, Stavros G.; Negres, Raluca A.

2016-09-08

A volume of superheated material reaching localized temperatures of the order of 1 eV and pressures of the order of 10 GPa is generated following laser-induced damage (breakdown) on the surface of transparent dielectric materials using nanosecond pulses. This leads to material ejection and the formation of a crater. To elucidate the material behaviors involved, we examined the morphologies of the ejected particles and found distinctive features that support their classification into different types. The different morphologies arise from the difference in the structure and physical properties (such as the dynamic viscosity and presence of instabilities) of the superheated andmore » surrounding affected material at the time of ejection of each individual particle. In addition, the temperature and kinetic energy of a subset of the ejected particles were found to be sufficient to initiate irreversible modification on the intercepting silica substrates. Finally, the modifications observed are associated with mechanical damage and fusion of melted particles on the collector substrate.« less

Controllable synthesis and electrochemical hydrogen storage properties of Sb₂Se₃ ultralong nanobelts with urchin-like structures.

PubMed

Jin, Rencheng; Chen, Gang; Pei, Jian; Sun, Jingxue; Wang, Yang

2011-09-01

The controlled synthesis of one-dimensional and three-dimensional Sb(2)Se(3) nanostructures has been achieved by a facile solvothermal process in the presence of citric acid. By simply controlling the concentration of citric acid, the nucleation, growth direction and exposed facet can be readily tuned, which brings the different morphologies and nanostructures to the final products. The as-prepared products have been characterized by means of X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM and selected area electron diffraction. Based on the electron microscope observations, a possible growth mechanism of Sb(2)Se(3) with distinctive morphologies including ultralong nanobelts, hierarchical urchin-like nanostructures is proposed and discussed in detail. The electrochemical hydrogen storage measurements reveal that the morphology plays a key role on the hydrogen storage capacity of Sb(2)Se(3) nanostructures. The Sb(2)Se(3) ultralong nanobelts with high percentage of {-111} facets exhibit higher hydrogen storage capacity (228.5 mA h g(-1)) and better cycle stability at room temperature.

Neurogenic and cardiomyogenic differentiation of mesenchymal stem cells isolated from minipig bone marrow.

PubMed

Kumar, B Mohana; Maeng, Geun-Ho; Lee, Yeon-Mi; Kim, Tae-Ho; Lee, Jeong-Hyeon; Jeon, Byeong-Gyun; Ock, Sun-A; Yoo, Jae-Gyu; Rho, Gyu-Jin

2012-10-01

The present study investigated the potential of minipig bone marrow-mesenchymal stem cells (BM-MSCs) to differentiate in vitro into neuron- and cardiomyocyte-like cells. Isolated BM-MSCs exhibited a fibroblast-like morphology, expressed CD29, CD44 and CD90, and differentiated into osteocytes, adipocytes and chondrocytes. Upon induction in two different neuronal specific media, most of BM-MSCs acquired the distinctive morphological features and positively stained for nestin, neurofilament-M (NF-M), neuronal nuclei (NeuN), β-tubulin, galactocerebroside (Gal-C) and glial fibrillary acidic protein (GFAP). Expression of nestin, GFAP and NF-M was further demonstrated by RT-PCR and RT-qPCR. Following cardiomyogenic induction, MSCs exhibited a stick-like morphology with extended cytoplasmic processes, and formed cluster-like structures. The expression of cardiac specific markers α-smooth muscle actin, cardiac troponin T, desmin and α-cardiac actin was positive for immunofluorescence staining, and further confirmed by RT-PCR and RT-qPCR. In conclusion, our results showed the in vitro differentiation ability of porcine BM-MSCs into neuron-like and cardiomyocyte-like cells. Copyright © 2011 Elsevier Ltd. All rights reserved.

Investigation of cell viability and morphology in 3D bio-printed alginate constructs with tunable stiffness.

PubMed

Shi, Pujiang; Laude, Augustinus; Yeong, Wai Yee

2017-04-01

In this article, mouse fibroblast cells (L929) were seeded on 2%, 5%, and 10% alginate hydrogels, and they were also bio-printed with 2%, 5%, and 10% alginate solutions individually to form constructs. The elastic and viscous moduli of alginate solutions, their interior structure and stiffness, interactions of cells and alginate, cell viability, migration and morphology were investigated by rheometer, MTT assay, scanning electron microscope (SEM), and fluorescent microscopy. The three types of bio-printed scaffolds of distinctive stiffness were prepared, and the seeded cells showed robust viability either on the alginate hydrogel surfaces or in the 3D bio-printed constructs. Majority of the proliferated cells in the 3D bio-printed constructs weakly attached to the surrounding alginate matrix. The concentration of alginate solution and hydrogel stiffness influenced cell migration and morphology, moreover the cells formed spheroids in the bio-printed 10% alginate hydrogel construct. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1009-1018, 2017. © 2017 Wiley Periodicals, Inc.

Surface topography during neural stem cell differentiation regulates cell migration and cell morphology.

PubMed

Czeisler, Catherine; Short, Aaron; Nelson, Tyler; Gygli, Patrick; Ortiz, Cristina; Catacutan, Fay Patsy; Stocker, Ben; Cronin, James; Lannutti, John; Winter, Jessica; Otero, José Javier

2016-12-01

We sought to determine the contribution of scaffold topography to the migration and morphology of neural stem cells by mimicking anatomical features of scaffolds found in vivo. We mimicked two types of central nervous system scaffolds encountered by neural stem cells during development in vitro by constructing different diameter electrospun polycaprolactone (PCL) fiber mats, a substrate that we have shown to be topographically similar to brain scaffolds. We compared the effects of large fibers (made to mimic blood vessel topography) with those of small-diameter fibers (made to mimic radial glial process topography) on the migration and differentiation of neural stem cells. Neural stem cells showed differential migratory and morphological reactions with laminin in different topographical contexts. We demonstrate, for the first time, that neural stem cell biological responses to laminin are dependent on topographical context. Large-fiber topography without laminin prevented cell migration, which was partially reversed by treatment with rock inhibitor. Cell morphology complexity assayed by fractal dimension was inhibited in nocodazole- and cytochalasin-D-treated neural precursor cells in large-fiber topography, but was not changed in small-fiber topography with these inhibitors. These data indicate that cell morphology has different requirements on cytoskeletal proteins dependent on the topographical environment encountered by the cell. We propose that the physical structure of distinct scaffolds induces unique signaling cascades that regulate migration and morphology in embryonic neural precursor cells. J. Comp. Neurol. 524:3485-3502, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Seafloor morphology in the different domains of the Calabrian Arc subduction complex - Ionian Sea

NASA Astrophysics Data System (ADS)

Riminucci, F.; Polonia, A.; Torelli, L.; Mussoni, P.

2010-05-01

The Calabrian Arc (CA) is a subduction system that develops along the African-Eurasian plate boundary in the Ionian Sea and connects the E-W trending Sicilian Maghrebian belt with the NW-SE trending Southern Apennines. The first systematic geophysical investigation in the offshore region of the CA was conducted during the 70's by the Institute of Marine Geology (now ISMAR) with the R/V 'Bannock' [1]. In the last 30 years, further geophysical data (high penetration multichannel seismics, CHIRP and multibeam data) has been acquired in the offshore of the CA, down to the Ionian Abyssal Plain. The integrated interpretation of the existing geophysical data [2] has outlined the regional architecture of the subduction complex, the main tectonic features absorbing plate motion and variation of seafloor morphology in the different structural domains. Pre-stack depth migrated seismic profiles has revealed that the accretionary complex is constituted by two distinct wedges whose geometry, structural style and seafloor morphology widely vary. The outermost accretionary wedge has been emplaced in post-messinian times. It is a salt-bearing complex as pointed out by the internal structure of the wedge (acoustically transparent assemblage), very low taper angle and high seismic velocities. The seafloor shows a rough morphology, short wavelength folds and depressions superimposed on a rather constant gentle regional slope. Landward of the outer wedge, the evaporites are no longer present and the transition to the clastic rock assemblage is reflected in a different structural architecture, which shows steeper slopes and a succession of topographic scarps separated by sedimentary basins and mid slope terraces. The topographic scarps are controlled in depth by a series of high angle landward dipping reflectors, that we interpreted as out of sequence thrust faults absorbing shortening at the rear of the wedge. Landward of the inner wedge a mid slope terrace develops (inner plateau) between 1300 and 1600 m water depth. It is a relatively flat area of variable width ranging from 10 to 50 Km, represented by the forearc basin and the innermost accretionary wedge. Seafloor morphology is related to small undulation of the seafloor. A thick section of Plio-Quaternary and Messinian sediments is present below the flat terrace. Sediments appear to be folded and, in some regions highly disrupted along local sub-circular structures that affect the seafloor morphology as well. Geometry and seismic facies of these sub-circular swells rising from the surrounding suggest they are diapiric structures. Variation of seafloor morphology is strictly related to the progression of structural domains within the Calabrian Arc subduction complex. The integrated analysis of seafloor morphology and structural style through an integrated approach involving the interpretation of seismic data at different scales has been carried out in order to outline relationships between shallow tectonic processes and deep structures. Moreover, the analysis of morphobathymetric and seismic data, combined with well targeted sediment samples has the potential to reveal relationships between tectonics, sedimentation and fluid flow in the different portions of the accretionary wedge. References: 1 - Rossi S., Sartori R. 1981. A seismic reflection study of the External Calabrian Arc in the Northern Ionian Sea (Eastern Mediterranean). Marine Geoph. Res., 4, 403-426. 2 - Polonia A. et al., The Calabrian Arc subduction complex: plate convergence, active faults, and mud diapirism. New results from the CALAMARE-2008 cruise (N/R CNR Urania). Submitted to G3.

Effect of Morphology and Manganese Valence on the Voltage Fade and Capacity Retention of Li[Li 2/12Ni 3/12Mn 7/12]O 2

DOE PAGES

Verde, Michael G.; Liu, Haodong; Carroll, Kyler J.; ...

2014-10-02

We have determined the electrochemical characteristics of the high voltage, high capacity Li-ion battery cathode material Li[Li 2/12Ni 3/12Mn 7/12]O 2 prepared using three different synthesis routes: sol-gel, hydroxide co-precipitation, and carbonate co-precipitation. Each route leads to distinct morphologies and surface areas while maintaining the same crystal structures. X-ray photoelectron spectroscopy (XPS) measurements reveal differences in their surface chemistries upon cycling, which correlate with voltage fading. As expected, we observed the valence state of Mn on the surface to decrease upon lithiation, and this reduction is specifically correlated to discharging below 3.6V. Furthermore, the data shows a correlation of themore » formation of Li 2CO 3 with Mn oxidation state from the« less

Mind the gap: Neural coding of species identity in birdsong prosody.

PubMed

Araki, Makoto; Bandi, M M; Yazaki-Sugiyama, Yoko

2016-12-09

Juvenile songbirds learn vocal communication from adult tutors of the same species but not from adults of other species. How species-specific learning emerges from the basic features of song prosody remains unknown. In the zebra finch auditory cortex, we discovered a class of neurons that register the silent temporal gaps between song syllables and are distinct from neurons encoding syllable morphology. Behavioral learning and neuronal coding of temporal gap structure resisted song tutoring from other species: Zebra finches fostered by Bengalese finch parents learned Bengalese finch song morphology transposed onto zebra finch temporal gaps. During the vocal learning period, temporal gap neurons fired selectively to zebra finch song. The innate temporal coding of intersyllable silent gaps suggests a neuronal barcode for conspecific vocal learning and social communication in acoustically diverse environments. Copyright © 2016, American Association for the Advancement of Science.

Spatial Patterns of Carbonate Biomineralization in Biofilms

PubMed Central

Li, Xiaobao; Chopp, David L.; Russin, William A.; Brannon, Paul T.; Parsek, Matthew R.

2015-01-01

Microbially catalyzed precipitation of carbonate minerals is an important process in diverse biological, geological, and engineered systems. However, the processes that regulate carbonate biomineralization and their impacts on biofilms are largely unexplored, mainly because of the inability of current methods to directly observe biomineralization within biofilms. Here, we present a method for in situ, real-time imaging of biomineralization in biofilms and use it to show that Pseudomonas aeruginosa biofilms produce morphologically distinct carbonate deposits that substantially modify biofilm structures. The patterns of carbonate biomineralization produced in situ were substantially different from those caused by accumulation of particles produced by abiotic precipitation. Contrary to the common expectation that mineral precipitation should occur at the biofilm surface, we found that biomineralization started at the base of the biofilm. The carbonate deposits grew over time, detaching biofilm-resident cells and deforming the biofilm morphology. These findings indicate that biomineralization is a general regulator of biofilm architecture and properties. PMID:26276112

Early photosynthetic microorganisms and environmental evolution

NASA Technical Reports Server (NTRS)

Golubic, S.

1980-01-01

Microfossils which are preserved as shrivelled kerogenous residues provide little information about cellular organization and almost none about the metabolic properties of the organisms. The distinction between prokaryotic vs eukaryotic, and phototrophic vs chemo- and organotrophic fossil microorganisms rests entirely on morphological comparisons with recent counterparts. The residual nature of the microbial fossil record promotes the conclusion that it must be biased toward (a) most abundant organisms, (b) those most resistant to degradation, and (c) those inhabiting environments with high preservation potential e.g., stromatolites. These criteria support the cyanophyte identity of most Precambrian microbial fossils on the following grounds: (1) as primary producers they dominate prokaryotic communities in modern extreme environments, e.g., intertidal zone; (2) several morphological counterparts of modern cyanophytes and microbial fossils have been established based on structure, cell division patterns and degradation sequences. The impact of anaerobic and oxygenic microbial photosynthesis on the evolution of Precambrian environments is discussed.

Mycophagous rove beetles highlight diverse mushrooms in the Cretaceous

PubMed Central

Cai, Chenyang; Leschen, Richard A. B.; Hibbett, David S; Xia, Fangyuan; Huang, Diying

2017-01-01

Agaricomycetes, or mushrooms, are familiar, conspicuous and morphologically diverse Fungi. Most Agaricomycete fruiting bodies are ephemeral, and their fossil record is limited. Here we report diverse gilled mushrooms (Agaricales) and mycophagous rove beetles (Staphylinidae) from mid-Cretaceous Burmese amber, the latter belonging to Oxyporinae, modern members of which exhibit an obligate association with soft-textured mushrooms. The discovery of four mushroom forms, most with a complete intact cap containing distinct gills and a stalk, suggests evolutionary stasis of body form for ∼99 Myr and highlights the palaeodiversity of Agaricomycetes. The mouthparts of early oxyporines, including enlarged mandibles and greatly enlarged apical labial palpomeres with dense specialized sensory organs, match those of modern taxa and suggest that they had a mushroom feeding biology. Diverse and morphologically specialized oxyporines from the Early Cretaceous suggests the existence of diverse Agaricomycetes and a specialized trophic interaction and ecological community structure by this early date. PMID:28300055

The one-step electroposition of superhydrophobic surface on AZ31 magnesium alloy and its time-dependence corrosion resistance in NaCl solution

NASA Astrophysics Data System (ADS)

Zhong, Yuxing; Hu, Jin; Zhang, Yufen; Tang, Shawei

2018-01-01

A calcium myristic superhydrophobicity coating with a hierarchical micro-nanostructure was fabricated on AZ31 magnesium alloy by one-step electroposition. The effects of deposition time on the coating structure, such as morphology, thickness, wettability and phase composition of the coating were studied. The corrosion behavior of the coated samples in 3.5% NaCl solution was also investigated and the corrosion mechanism was discussed. It was found that the deposition time has a visible effect on the morphology, thickness and wettability, which distinctly affects the corrosion resistance of coatings. The corrosion resistance of the coating gradually decreases with the increase in the immersion time due to the disappearance of the air layer which exists on the coating surface. The superhydrophobic surfaces present the temporal limitations to the corrosion resistance of AZ31 magnesium alloy.

The Roots of Linguistic Organization in a New Language*

PubMed Central

Aronoff, Mark; Meir, Irit; Padden, Carol; Sandler, Wendy

2011-01-01

It is possible for a language to emerge with no direct linguistic history or outside linguistic influence. Al-Sayyid Bedouin Sign Language (ABSL) arose about 70 years ago in a small, insular community with a high incidence of profound prelingual neurosensory deafness. In ABSL, we have been able to identify the beginnings of phonology, morphology, syntax, and prosody. The linguistic elements we find in ABSL are not exclusively holistic, nor are they all compositional, but a combination of both. We do not, however, find in ABSL certain features that have been posited as essential even for a proto-language. ABSL has a highly regular syntax as well as word-internal compounding, also highly regular but quite distinct from syntax in its patterns. ABSL, however, has no discernable word-internal structure of the kind observed in more mature sign languages: no spatially organized morphology and no evident duality of phonological patterning. PMID:22448152

A review of the North American genus Epimartyria (Lepidoptera, Micropterigidae) with a discussion of the larval plastron

PubMed Central

Davis, Donald R.; Landry, Jean-François

2012-01-01

Abstract The indigenous North American micropterigid genus Epimartyria Walsingham,1898 is revised. Three species are recognized, including Epimartyria auricrinella Walsingham, 1898 which occurs widely over much of the northeastern United States and Canada, a new species, Epimartyria bimaculella Davis & Landry from northwestern United States and Canada, and Epimartyria pardella (Walsingham, 1880) from northern California to northern Oregon. The larva of Epimartyria auricrinella is described in detail, supplemented with illustrations of the external structure of the larval integument. The larval plastron is described and illustrated for Epimartyria, and this is compared with the plastrons of Neomicropteryx Issiki, 1931 and Micropterix Hübner, 1825. COI barcode sequences show that the three species are genetically distinct, congruent with morphological differences. Marked haplotype divergence within some Epimartyria auricrinella populations appears to be unrelated to morphology, geography or phenology. PMID:22573948

Influence of topographically patterned angled guidelines on directed self-assembly of block copolymers

NASA Astrophysics Data System (ADS)

Rebello, Nathan; Sethuraman, Vaidyanathan; Blachut, Gregory; Ellison, Christopher J.; Willson, C. Grant; Ganesan, Venkat

2017-11-01

Single chain in mean-field Monte Carlo simulations were employed to study the self-assembly of block copolymers (BCP) in thin films that use trapezoidal guidelines to direct the orientation and alignment of lamellar patterns. The present study explored the influence of sidewall interactions and geometry of the trapezoidal guidelines on the self-assembly of perpendicularly oriented lamellar morphologies. When both the sidewall and the top surface exhibit preferential interactions to the same block of the BCP, trapezoidal guidelines with intermediate taper angles were found to result in less defective perpendicularly orientated morphologies. Similarly, when the sidewall and top surface are preferential to distinct blocks of the BCP, intermediate tapering angles were found to be optimal in promoting defect free structures. Such results are rationalized based on the energetics arising in the formation of perpendicularly oriented lamella on patterned substrates.

Three-dimensional behavior of ice crystals and biological cells during freezing of cell suspensions.

PubMed

Ishiguro, H; Koike, K

1998-09-11

Behavior of ice crystals and human red blood cells during extracellular-freezing was investigated in three-dimensions using a confocal laser scanning microscope(CLSM), which noninvasively produces tomograms of biological materials. Physiological saline and physiological saline with 2.4 M glycerol were used for suspension. Various cooling rates for directional solidification were used for distinctive morphology of the ice crystals. Addition of acridine orange as a fluorescent dye into the cell suspension enabled ice crystal, cells and unfrozen solution to be distinguished by different colors. The results indicate that the microscopic structure is three-dimensional for flat, cellular, and dendritic solid-liquid interfaces and that a CLSM is very effective in studying three-dimensional structure during the freezing of cell suspensions.

Morphology of large valleys on Hawaii - Evidence for groundwater sapping and comparisons with Martian valleys

NASA Technical Reports Server (NTRS)

Kochel, R. Craig; Piper, Jonathan F.

1986-01-01

Morphometric data on the runoff and sapping valleys on the slopes of Hawaii and Molokai in Hawaii are analyzed. The analysis reveals a clear distinction between the runoff valleys and sapping valleys. The Hawaiian sapping valleys are characterized by: (1) steep valley walls and flat floors, (2) amphitheater heads, (3) low drainage density, (4) paucity of downstream tributaries, (5) low frequency of up-dip tributaries, and (6) structural and stratigraphic control on valley patterns. The characteristics of the Hawaiian sapping valleys are compared to Martian valleys and experimental systems, and good correlation between the data is detected. Flume experiments were also conducted to study the evolution of sapping valleys in response to variable structure and stratigraphy.

Synthesis-driven, structure-dependent optical behavior in phase-tunable NaYF 4:Yb,Er-based motifs and associated heterostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Haiqing; Han, Jinkyu; McBean, Coray

Understanding the key parameters necessary for generating uniform Er,Yb co-activated NaYF 4 possessing various selected phases (i.e. cubic or hexagonal) represents an important chemical strategy towards tailoring optical behavior in these systems. In this paper, we report on a straightforward hydrothermal synthesis in which the separate effects of reaction temperature, reaction time, and precursor stoichiometry in the absence of any surfactant were independently investigated. Interestingly, the presence and the concentration of NH 4OH appear to be the most critical determinants of the phase and morphology. For example, with NH 4OH as an additive, we have observed the formation of novelmore » hierarchical nanowire bundles which possess overall lengths of ~5 μm and widths of ~1.5 μm but are composed of constituent component sub-units of long, ultrathin (~5 nm) nanowires. These motifs have yet to be reported as distinctive morphological manifestations of fluoride materials. The optical properties of as-generated structures have also been carefully analyzed. Specifically, we have observed tunable, structure-dependent energy transfer behavior associated with the formation of a unique class of NaYF 4–CdSe quantum dot (QD) heterostructures, incorporating zero-dimensional (0D), one-dimensional (1D), and three-dimensional (3D) NaYF 4 structures. Our results have demonstrated the key roles of the intrinsic morphology-specific physical surface area and porosity as factors in governing the resulting opto-electronic behavior. Finally and specifically, the trend in energy transfer efficiency correlates well with the corresponding QD loading within these heterostructures, thereby implying that the efficiency of FRET appears to be directly affected by the amount of QDs immobilized onto the external surfaces of the underlying fluoride host materials.« less

Synthesis-driven, structure-dependent optical behavior in phase-tunable NaYF 4:Yb,Er-based motifs and associated heterostructures

DOE PAGES

Liu, Haiqing; Han, Jinkyu; McBean, Coray; ...

2017-01-03

Understanding the key parameters necessary for generating uniform Er,Yb co-activated NaYF 4 possessing various selected phases (i.e. cubic or hexagonal) represents an important chemical strategy towards tailoring optical behavior in these systems. In this paper, we report on a straightforward hydrothermal synthesis in which the separate effects of reaction temperature, reaction time, and precursor stoichiometry in the absence of any surfactant were independently investigated. Interestingly, the presence and the concentration of NH 4OH appear to be the most critical determinants of the phase and morphology. For example, with NH 4OH as an additive, we have observed the formation of novelmore » hierarchical nanowire bundles which possess overall lengths of ~5 μm and widths of ~1.5 μm but are composed of constituent component sub-units of long, ultrathin (~5 nm) nanowires. These motifs have yet to be reported as distinctive morphological manifestations of fluoride materials. The optical properties of as-generated structures have also been carefully analyzed. Specifically, we have observed tunable, structure-dependent energy transfer behavior associated with the formation of a unique class of NaYF 4–CdSe quantum dot (QD) heterostructures, incorporating zero-dimensional (0D), one-dimensional (1D), and three-dimensional (3D) NaYF 4 structures. Our results have demonstrated the key roles of the intrinsic morphology-specific physical surface area and porosity as factors in governing the resulting opto-electronic behavior. Finally and specifically, the trend in energy transfer efficiency correlates well with the corresponding QD loading within these heterostructures, thereby implying that the efficiency of FRET appears to be directly affected by the amount of QDs immobilized onto the external surfaces of the underlying fluoride host materials.« less

Unexpected diversity of Anopheles species in Eastern Zambia: implications for evaluating vector behavior and interventions using molecular tools.

PubMed

Lobo, Neil F; St Laurent, Brandyce; Sikaala, Chadwick H; Hamainza, Busiku; Chanda, Javan; Chinula, Dingani; Krishnankutty, Sindhu M; Mueller, Jonathan D; Deason, Nicholas A; Hoang, Quynh T; Boldt, Heather L; Thumloup, Julie; Stevenson, Jennifer; Seyoum, Aklilu; Collins, Frank H

2015-12-09

The understanding of malaria vector species in association with their bionomic traits is vital for targeting malaria interventions and measuring effectiveness. Many entomological studies rely on morphological identification of mosquitoes, limiting recognition to visually distinct species/species groups. Anopheles species assignments based on ribosomal DNA ITS2 and mitochondrial DNA COI were compared to morphological identifications from Luangwa and Nyimba districts in Zambia. The comparison of morphological and molecular identifications determined that interpretations of species compositions, insecticide resistance assays, host preference studies, trap efficacy, and Plasmodium infections were incorrect when using morphological identification alone. Morphological identifications recognized eight Anopheles species while 18 distinct sequence groups or species were identified from molecular analyses. Of these 18, seven could not be identified through comparison to published sequences. Twelve of 18 molecularly identified species (including unidentifiable species and species not thought to be vectors) were found by PCR to carry Plasmodium sporozoites - compared to four of eight morphological species. Up to 15% of morphologically identified Anopheles funestus mosquitoes in insecticide resistance tests were found to be other species molecularly. The comprehension of primary and secondary malaria vectors and bionomic characteristics that impact malaria transmission and intervention effectiveness are fundamental in achieving malaria elimination.

A revision of Boletellus sect. Ixocephali

Treesearch

Roy E. Halling; Beatriz Ortiz-Santana

2009-01-01

Taxa included in Boletellus section Ixocephali sensu Singer are re-evaluated and species limits are clarified in a morphological context. In this revision, we recognize four distinct morphological species: B. jalapensis, B. elatus, B. longicollis, and B. singerii. Among these, we have...

Internal structures of scaffold-free 3D cell cultures visualized by synchrotron radiation-based micro-computed tomography

NASA Astrophysics Data System (ADS)

Saldamli, Belma; Herzen, Julia; Beckmann, Felix; Tübel, Jutta; Schauwecker, Johannes; Burgkart, Rainer; Jürgens, Philipp; Zeilhofer, Hans-Florian; Sader, Robert; Müller, Bert

2008-08-01

Recently the importance of the third dimension in cell biology has been better understood, resulting in a re-orientation towards three-dimensional (3D) cultivation. Yet adequate tools for their morphological characterization have to be established. Synchrotron radiation-based micro computed tomography (SRμCT) allows visualizing such biological systems with almost isotropic micrometer resolution, non-destructively. We have applied SRμCT for studying the internal morphology of human osteoblast-derived, scaffold-free 3D cultures, termed histoids. Primary human osteoblasts, isolated from femoral neck spongy bone, were grown as 2D culture in non-mineralizing osteogenic medium until a rather thick, multi-cellular membrane was formed. This delicate system was intentionally released to randomly fold itself. The folded cell cultures were grown to histoids of cubic milli- or centimeter size in various combinations of mineralizing and non-mineralizing osteogenic medium for a total period of minimum 56 weeks. The SRμCT-measurements were performed in the absorption contrast mode at the beamlines BW 2 and W 2 (HASYLAB at DESY, Hamburg, Germany), operated by the GKSS-Research Center. To investigate the entire volume of interest several scans were performed under identical conditions and registered to obtain one single dataset of each sample. The histoids grown under different conditions exhibit similar external morphology of globular or ovoid shape. The SRμCT-examination revealed the distinctly different morphological structures inside the histoids. One obtains details of the histoids that permit to identify and select the most promising slices for subsequent histological characterization.

The concerted impact of galaxies and QSOs on the ionization and thermal state of the intergalactic medium

NASA Astrophysics Data System (ADS)

Kakiichi, Koki; Graziani, Luca; Ciardi, Benedetta; Meiksin, Avery; Compostella, Michele; Eide, Marius B.; Zaroubi, Saleem

2017-07-01

We present a detailed analysis of the ionization and thermal structure of the intergalactic medium (IGM) around a high-redshift (z = 10) QSO, using a large suite of cosmological, multifrequency radiative transfer simulations, exploring the contribution from galaxies as well as the QSO, and the effect of X-rays and secondary ionization. We show that in high-z QSO environments both the central QSO and the surrounding galaxies concertedly control the reionization morphology of hydrogen and helium and have a non-linear impact on the thermal structure of the IGM. A QSO imprints a distinctive morphology on H II regions if its total ionizing photon budget exceeds that of the surrounding galaxies since the onset of hydrogen reionization; otherwise, the morphology shows little difference from that of H II regions produced only by galaxies. In addition, the spectral shape of the collective radiation field from galaxies and QSOs controls the thickness of the I-fronts. While a UV-obscured QSO can broaden the I-front, the contribution from other UV sources, either galaxies or unobscured QSOs, is sufficient to maintain a sharp I-front. X-ray photons from the QSO are responsible for a prominent extended tail of partial ionization ahead of the I-front. QSOs leave a unique imprint on the morphology of He II/He III regions. We suggest that, while the physical state of the IGM is modified by QSOs, the most direct test to understand the role of galaxies and QSOs during reionization is to perform galaxy surveys in a region of sky imaged by 21 cm tomography.

Detecting hybridization in African schistosome species: does egg morphology complement molecular species identification?

PubMed

Boon, Nele A M; Fannes, Wouter; Rombouts, Sara; Polman, Katja; Volckaert, Filip A M; Huyse, Tine

2017-06-01

Hybrid parasites may have an increased transmission potential and higher virulence compared to their parental species. Consequently, hybrid detection is critical for disease control. Previous crossing experiments showed that hybrid schistosome eggs have distinct morphotypes. We therefore compared the performance of egg morphology with molecular markers with regard to detecting hybridization in schistosomes. We studied the morphology of 303 terminal-spined eggs, originating from 19 individuals inhabiting a hybrid zone with natural crosses between the human parasite Schistosoma haematobium and the livestock parasite Schistosoma bovis in Senegal. The egg sizes showed a high variability and ranged between 92·4 and 176·4 µm in length and between 35·7 and 93·0 µm in width. No distinct morphotypes were found and all eggs resembled, to varying extent, the typical S. haematobium egg type. However, molecular analyses on the same eggs clearly showed the presence of two distinct partial mitochondrial cox1 profiles, namely S. bovis and S. haematobium, and only a single nuclear ITS rDNA profile (S. haematobium). Therefore, in these particular crosses, egg morphology appears not a good indicator of hybrid ancestry. We conclude by discussing strengths and limitations of molecular methods to detect hybrids in the context of high-throughput screening of field samples.

Tongue and taste organ development in the ontogeny of direct-developing salamander Plethodon cinereus (Lissamphibia: Plethodontidae).

PubMed

Budzik, Karolina A; Żuwała, Krystyna; Kerney, Ryan

2016-07-01

The latest research on direct developing caecilian and anuran species indicate presence of only one generation of taste organs during their ontogeny. This is distinct from indirect developing batrachians studied thus far, which possess taste buds in larvae and anatomically distinct taste discs in metamorphs. This study is a description of the tongue and taste organ morphology and development in direct developing salamander Plethodon cinereus (Plethodontidae) using histology and electron microscopy techniques. The results reveal two distinct stages tongue morphology (primary and secondary), similar to metamorphic urodeles, although only one stage of taste organ morphology. Taste disc sensory zones emerge on the surface of the oropharyngeal epithelium by the end of embryonic development, which coincides with maturation of the soft tongue. Taste organs occur in the epithelium of the tongue pad (where they are situated on the dermal papillae), the palate and the inner surface of the mandible and the maxilla. Plethodon cinereus embryos only possess taste disc type taste organs. Similar to the direct developing anuran Eleutherodactylus coqui (Eleutherodactylidae), these salamanders do not recapitulate larval taste bud morphology as an embryo. The lack of taste bud formation is probably a broadly distributed feature characteristic to direct developing batrachians. J. Morphol. 277:906-915, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

MORPHOLOGICAL AND PATHOGENIC VARIATIONS IN TREPONEMA PALLIDUM

PubMed Central

Noguchi, Hideyo

1912-01-01

When many cultures of Treponema pallidum, whether obtained from the testicular lesions produced in rabbits or directly from human cases of syphilis, are compared, certain definite differences in morphological character become apparent. The different specimens can be divided into thicker and thinner forms or types, and an average or normal form or type. The last is the common or most frequent variety, but the other two occur with sufficient frequency and retain their characters with such constancy as to constitute distinct varieties. Indeed, two of the varieties—the average and the thinner—occurred in association in a chancre and were separated afterwards in cultures. The gross cultural properties of the three varieties present no points of distinction. The lesions caused in the testicle of the rabbit differ according to the variety inoculated, and consist either of a diffuse or of a nodular orchitis. This is a highly important distinction, and if, in the study of a still larger number of specimens of pallida, it is maintained, it is capable of throwing light on certain important clinical features of the human syphilitic disease. The thinner variety of Treponema pallidum resembles in morphology Treponema microdentium, from which it is unmistakably distinguished by cultural characters. The morphological and pathogenic variations in cultures of the pallidum may constitute racial differences within the species. PMID:19867516

Does Structural Complexity Determine the Morphology of Assemblages? An Experimental Test on Three Continents

PubMed Central

Gibb, Heloise; Parr, Catherine L.

2013-01-01

Understanding how species will respond to global change depends on our ability to distinguish generalities from idiosyncrasies. For diverse, but poorly known taxa, such as insects, species traits may provide a short-cut to predicting species turnover. We tested whether ant traits respond consistently to habitat complexity across geographically independent ant assemblages, using an experimental approach and baits. We repeated our study in six paired simple and complex habitats on three continents with distinct ant faunas. We also compared traits amongst ants with different foraging strategies. We hypothesised that ants would be larger, broader, have longer legs and more dorsally positioned eyes in simpler habitats. In agreement with predictions, ants had longer femurs and dorsally positioned eyes in simple habitats. This pattern was most pronounced for ants that discovered resources. Body size and pronotum width responded as predicted for experimental treatments, but were inconsistent across continents. Monopolising ants were smaller, with shorter femurs than those that occupied or discovered resources. Consistent responses for several traits suggest that many, but not all, aspects of morphology respond predictably to habitat complexity, and that foraging strategy is linked with morphology. Some traits thus have the potential to be used to predict the direction of species turnover, changes in foraging strategy and, potentially, evolution in response to changes in habitat structure. PMID:23691137

Silver-cotton nanocomposites: Nano-design of microfibrillar structure causes morphological changes and increased tenacity

PubMed Central

Nam, Sunghyun; Condon, Brian D.; Delhom, Christopher D.; Fontenot, Krystal R.

2016-01-01

The interactions of nanoparticles with polymer hosts have important implications for directing the macroscopic properties of composite fibers, yet little is known about such interactions with hierarchically ordered natural polymers due to the difficulty of achieving uniform dispersion of nanoparticles within semi-crystalline natural fiber. In this study we have homogeneously dispersed silver nanoparticles throughout an entire volume of cotton fiber. The resulting electrostatic interaction and distinct supramolecular structure of the cotton fiber provided a favorable environment for the controlled formation of nanoparticles (12 ± 3 nm in diameter). With a high surface-to-volume ratio, the extensive interfacial contacts of the nanoparticles efficiently “glued” the structural elements of microfibrils together, producing a unique inorganic-organic hybrid substructure that reinforced the multilayered architecture of the cotton fiber. PMID:27849038

Epitaxially Grown Films of Standing and Lying Pentacene Molecules on Cu(110) Surfaces

PubMed Central

2011-01-01

Here, it is shown that pentacene thin films (30 nm) with distinctively different crystallographic structures and molecular orientations can be grown under essentially identical growth conditions in UHV on clean Cu(110) surfaces. By X-ray diffraction, we show that the epitaxially oriented pentacene films crystallize either in the “thin film” phase with standing molecules or in the “single crystal” structure with molecules lying with their long axes parallel to the substrate. The morphology of the samples observed by atomic force microscopy shows an epitaxial alignment of pentacene crystallites, which corroborates the molecular orientation observed by X-ray diffraction pole figures. Low energy electron diffraction measurements reveal that these dissimilar growth behaviors are induced by subtle differences in the monolayer structures formed by slightly different preparation procedures. PMID:21479111

Allopatric Speciation within a Cryptic Species Complex of Australasian Octopuses

PubMed Central

Amor, Michael D.; Norman, Mark D.; Cameron, Hayley E.; Strugnell, Jan M.

2014-01-01

Despite extensive revisions over recent decades, the taxonomy of benthic octopuses (Family Octopodidae) remains in a considerable flux. Among groups of unresolved status is a species complex of morphologically similar shallow-water octopods from subtropical Australasia, including: Allopatric populations of Octopus tetricus on the eastern and western coasts of Australia, of which the Western Australian form is speculated to be a distinct or sub-species; and Octopus gibbsi from New Zealand, a proposed synonym of Australian forms. This study employed a combination of molecular and morphological techniques to resolve the taxonomic status of the ‘tetricus complex’. Phylogenetic analyses (based on five mitochondrial genes: 12S rRNA, 16S rRNA, COI, COIII and Cytb) and Generalised Mixed Yule Coalescent (GMYC) analysis (based on COI, COIII and Cytb) distinguished eastern and Western Australian O. tetricus as distinct species, while O. gibbsi was found to be synonymous with the east Australian form (BS = >97, PP = 1; GMYC p = 0.01). Discrete morphological differences in mature male octopuses (based on sixteen morphological traits) provided further evidence of cryptic speciation between east (including New Zealand) and west coast populations; although females proved less useful in morphological distinction among members of the tetricus complex. In addition, phylogenetic analyses suggested populations of octopuses currently treated under the name Octopus vulgaris are paraphyletic; providing evidence of cryptic speciation among global populations of O. vulgaris, the most commercially valuable octopus species worldwide. PMID:24964133

Numerical morphology supports early number word learning: Evidence from a comparison of young Mandarin and English learners

PubMed Central

Corre, Mathieu Le; Li, Peggy; Huang, Becky H.; Jia, Gisela; Carey, Susan

2016-01-01

Previous studies showed that children learning a language with an obligatory singular/plural distinction (Russian and English) learn the meaning of the number word for one earlier than children learning Japanese, a language without obligatory number morphology (Barner, Libenson, Cheung, & Takasaki, 2009; Sarnecka, Kamenskaya, Yamana, Ogura, & Yudovina, 2007). This can be explained by differences in number morphology, but it can also be explained by many other differences between the languages and the environments of the children who were compared. The present study tests the hypothesis that the morphological singular/plural distinction supports the early acquisition of the meaning of the number word for one by comparing young English learners to age and SES matched young Mandarin Chinese learners. Mandarin does not have obligatory number morphology but is more similar to English than Japanese in many crucial respects. Corpus analyses show that, compared to English learners, Mandarin learners hear number words more frequently, are more likely to hear number words followed by a noun, and are more likely to hear number words in contexts where they denote a cardinal value. Two tasks show that, despite these advantages, Mandarin learners learn the meaning of the number word for one three to six months later than do English learners. These results provide the strongest evidence to date that prior knowledge of the numerical meaning of the distinction between singular and plural supports the acquisition of the meaning of the number word for one. PMID:27423486

Adhesion and Atomic Structures of Gold on Ceria Nanostructures:The Role of Surface Structure and Oxidation State of Ceria Supports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Yuyuan; Wu, Zili; Wen, Jianguo

2015-01-01

Recent advances in heterogeneous catalysis have demonstrated that oxides supports with the same material but different shapes can result in metal catalysts with distinct catalytic properties. The shape-dependent catalysis was not well-understood owing to the lack of direct visualization of the atomic structures at metal-oxide interface. Herein, we utilized aberration-corrected electron microscopy and revealed the atomic structures of gold particles deposited on ceria nanocubes and nanorods with {100} or {111} facets exposed. For the ceria nanocube support, gold nanoparticles have extended atom layers at the metal-support interface. In contrast, regular gold nanoparticles and rafts are present on the ceria nanorodmore » support. After hours of water gas shift reaction, the extended gold atom layers and rafts vanish, which is associated with the decrease of the catalytic activities. By understanding the atomic structures of the support surfaces, metal-support interfaces, and morphologies of the gold particles, a direct structure-property relationship is established.« less

Unlocking the "Black box": internal female genitalia in Sepsidae (Diptera) evolve fast and are species-specific

PubMed Central

2010-01-01

Background The species-specificity of male genitalia has been well documented in many insect groups and sexual selection has been proposed as the evolutionary force driving the often rapid, morphological divergence. The internal female genitalia, in sharp contrast, remain poorly studied. Here, we present the first comparative study of the internal reproductive system of Sepsidae. We test the species-specificity of the female genitalia by comparing recently diverged sister taxa. We also compare the rate of change in female morphological characters with the rate of fast-evolving, molecular and behavioral characters. Results We describe the ectodermal parts of the female reproductive tract for 41 species representing 21 of the 37 described genera and define 19 morphological characters with discontinuous variation found in eight structures that are part of the reproductive tract. Using a well-resolved molecular phylogeny based on 10 genes, we reconstruct the evolution of these characters across the family [120 steps; Consistency Index (CI): 0.41]. Two structures, in particular, evolve faster than the rest. The first is the ventral receptacle, which is a secondary sperm storage organ. It accounts for more than half of all the evolutionary changes observed (7 characters; 61 steps; CI: 0.46). It is morphologically diverse across genera, can be bi-lobed or multi-chambered (up to 80 chambers), and is strongly sclerotized in one clade. The second structure is the dorsal sclerite, which is present in all sepsids except Orygma luctuosum and Ortalischema albitarse. It is associated with the opening of the spermathecal ducts and is often distinct even among sister species (4 characters; 16 steps; CI: 0.56). Conclusions We find the internal female genitalia are diverse in Sepsidae and diagnostic for all species. In particular, fast-evolving structures like the ventral receptacle and dorsal sclerite are likely involved in post-copulatory sexual selection. In comparison to behavioral and molecular data, the female structures are evolving 2/3 as fast as the non-constant third positions of the COI barcoding gene. They display less convergent evolution in characters (CI = 0.54) than the third positions or sepsid mating behavior (CICOI = 0.36; CIBEHAV = 0.45). PMID:20831809

Morphologic interpretation of fertile structures in glossopterid gymnosperms

USGS Publications Warehouse

Schopf, J.M.

1976-01-01

The problem of determining affinity among glossopterid gymnosperms is beset by deficiencies in preservation, natural dissociation of parts, and scarcity of features assuredly critical for morphologic comprarison. The glossopterids probably are not a very heterogeneous group of plants, but this is difficult to prove. The Gondwana glacial "hiatus" has resulted in the omission of a critical chapter glossopterid evolution. As a consequence, morphologic features and phyletic probabilities must be evaluated on a much more hypothetical basis than would otherwise be justified. Confusion has arisen from the lack of morphologic terms that permit clear discussion of a newly evolved type of reproductive structure in glossopterids. The structure, here designated a "fertiliger", consists of a leafy bract, a partially adnate stalk, and a fertile head or capitulum. Seven types of fertile structures are discussed, all of which are bilaterally symmetrical and have different features on dorsiventral surfaces. I regard all fertiligers as ovulate but this interpretation may bot be acceptable to some workers; others may not accept dorsiventral organization of the capitulum as being fundamental. Among glossopterids, however, in spite of differences in preservation that may seem to support a variant interpretation, these ovulate fertiligers are the distinctive features that show general consistency. A single fertile bract bearing several capitula, as exemplified by Lidgettonia, is called a compound fertiliger. Staminate structures (microsporophylls) of glossopterids are separately classified as Eretmonia, Glossotheca, and possibly as other taxa. Only the manner of sporangial attachment is not entirely clear. It seems likely the staminate parts have previously been confused with scale leaves and are actually coextensive in distribution with the glossopterids. A tentative phyletic model suggests the distant derivation of glossopterids from middle Carboniferous cordaiteans. Many details must be speculative due to the lack of a pertinent fossil record, but this interpretation accounts for some features that have no counterpart in pteridosperms. Permineralized ovules from Antarctica provide general support for this working hypothesis, but specific evidence is lacking. Furthermore, it seems unlikely angiosperms originated from glossopterids; it is more reasonable to consider the glossopterids as possible distant ancestors of the Gnetales. ?? 1976.

Fluttering wing feathers produce the flight sounds of male streamertail hummingbirds.

PubMed

Clark, Christopher James

2008-08-23

Sounds produced continuously during flight potentially play important roles in avian communication, but the mechanisms underlying these sounds have received little attention. Adult male Red-billed Streamertail hummingbirds (Trochilus polytmus) bear elongated tail streamers and produce a distinctive 'whirring' flight sound, whereas subadult males and females do not. The production of this sound, which is a pulsed tone with a mean frequency of 858 Hz, has been attributed to these distinctive tail streamers. However, tail-less streamertails can still produce the flight sound. Three lines of evidence implicate the wings instead. First, it is pulsed in synchrony with the 29 Hz wingbeat frequency. Second, a high-speed video showed that primary feather eight (P8) bends during each downstroke, creating a gap between P8 and primary feather nine (P9). Manipulating either P8 or P9 reduced the production of the flight sound. Third, laboratory experiments indicated that both P8 and P9 can produce tones over a range of 700-900 Hz. The wings therefore produce the distinctive flight sound, enabled via subtle morphological changes to the structure of P8 and P9.

Morphological and molecular data for larval stages of four species of Petasiger Dietz, 1909 (Digenea: Echinostomatidae) with an updated key to the known cercariae from the Palaearctic.

PubMed

Selbach, Christian; Soldánová, Miroslava; Georgieva, Simona; Kostadinova, Aneta; Kalbe, Martin; Sures, Bernd

2014-10-01

Large-tailed echinostomatid cercariae of the genus Petasiger Dietz, 1909 (Digenea: Echinostomatidae) from the planorbid snails Gyraulus albus (Müller) and Planorbis planorbis (L.) collected in Germany and the Czech Republic and metacercariae from Gasterosteus aculeatus L. (Gasterosteiformes: Gasterosteidae) collected in Canada are characterised morphologically and molecularly. The rediae, cercariae and metacercariae are described in detail and compared with the existing data on the larval stages of Petasiger spp. Comparative molecular analyses using 28S rDNA and nad1 mitochondrial sequences supported the distinct status of four species of Petasiger. Molecular and morphological evidence for their distinction and an updated key to the known large-tailed cercariae of Petasiger from the Palaearctic are provided.

DNA Barcoding of Neotropical Sand Flies (Diptera, Psychodidae, Phlebotominae): Species Identification and Discovery within Brazil

PubMed Central

Pinto, Israel de Souza; Chagas, Bruna Dias das; Rodrigues, Andressa Alencastre Fuzari; Ferreira, Adelson Luiz; Rezende, Helder Ricas; Bruno, Rafaela Vieira; Falqueto, Aloisio; Andrade-Filho, José Dilermando; Galati, Eunice Aparecida Bianchi; Shimabukuro, Paloma Helena Fernandes; Brazil, Reginaldo Peçanha

2015-01-01

DNA barcoding has been an effective tool for species identification in several animal groups. Here, we used DNA barcoding to discriminate between 47 morphologically distinct species of Brazilian sand flies. DNA barcodes correctly identified approximately 90% of the sampled taxa (42 morphologically distinct species) using clustering based on neighbor-joining distance, of which four species showed comparatively higher maximum values of divergence (range 4.23–19.04%), indicating cryptic diversity. The DNA barcodes also corroborated the resurrection of two species within the shannoni complex and provided an efficient tool to differentiate between morphologically indistinguishable females of closely related species. Taken together, our results validate the effectiveness of DNA barcoding for species identification and the discovery of cryptic diversity in sand flies from Brazil. PMID:26506007

DNA Barcoding of Neotropical Sand Flies (Diptera, Psychodidae, Phlebotominae): Species Identification and Discovery within Brazil.

PubMed

Pinto, Israel de Souza; Chagas, Bruna Dias das; Rodrigues, Andressa Alencastre Fuzari; Ferreira, Adelson Luiz; Rezende, Helder Ricas; Bruno, Rafaela Vieira; Falqueto, Aloisio; Andrade-Filho, José Dilermando; Galati, Eunice Aparecida Bianchi; Shimabukuro, Paloma Helena Fernandes; Brazil, Reginaldo Peçanha; Peixoto, Alexandre Afranio

2015-01-01

DNA barcoding has been an effective tool for species identification in several animal groups. Here, we used DNA barcoding to discriminate between 47 morphologically distinct species of Brazilian sand flies. DNA barcodes correctly identified approximately 90% of the sampled taxa (42 morphologically distinct species) using clustering based on neighbor-joining distance, of which four species showed comparatively higher maximum values of divergence (range 4.23-19.04%), indicating cryptic diversity. The DNA barcodes also corroborated the resurrection of two species within the shannoni complex and provided an efficient tool to differentiate between morphologically indistinguishable females of closely related species. Taken together, our results validate the effectiveness of DNA barcoding for species identification and the discovery of cryptic diversity in sand flies from Brazil.

A sequential approach using genetic and morphological analyses to test species status: the case of United States federally endangered Agalinis acuta (Orobanchaceae).

PubMed

Pettengill, James B; Neel, Maile C

2011-05-01

Given that inaccurate taxonomy can have negative consequences for species of conservation concern and result in erroneous conclusions regarding macroecological patterns, efficient methods for resolving taxonomic uncertainty are essential. The primary objective of this study was to assess the evolutionary distinctiveness of the federally endangered plant species Agalinis acuta (Orobanchaceae) to ensure it represents a distinct taxon warranting protection under the United States Endangered Species Act. We describe and implement a sequential approach that begins with the most restrictive criteria of genealogical exclusivity within which we first conducted a phylogenetic analysis based on six chloroplast DNA loci assayed from multiple representatives of five putative species. Because of the possibility that incomplete lineage sorting is responsible for the lack of genealogical exclusivity among A. acuta individuals, we then conducted intensive population level analyses based on 21 microsatellite loci and 61 morphological traits. The distinctiveness of A. acuta from Agalinis decemloba and Agalinis tenella was not supported under the genealogical species concept. The results from the analyses of microsatellite loci and morphological characters evaluated under alternative species concepts also did not support the distinctiveness of A. acuta from A. decemloba . Through this successive approach, we found insufficient evidence to support the evolutionary distinctiveness of the listed taxon A. acuta . We recommend that it be synonymized under A. decemloba and also conclude that the taxon that would now include A. acuta is deserving of protection under the Endangered Species Act.

Ecological speciation by temporal isolation in a population of the stonefly Leuctra hippopus (Plecoptera, Leuctridae).

PubMed

Boumans, Louis; Hogner, Silje; Brittain, John; Johnsen, Arild

2017-03-01

Stream dwelling invertebrates are ideal candidates for the study of ecological speciation as they are often adapted to particular environmental conditions within a stream and inhabit only certain reaches of a drainage basin, separated by unsuitable habitat. We studied an atypical population of the stonefly Leuctra hippopus at a site in central Norway, the Isterfoss rapids, in relation to three nearby and two remote conspecific populations. Adults of this population emerge about a month earlier than those of nearby populations, live on large boulders emerging from the rapids, and are short-lived. This population also has distinct morphological features and was studied earlier during the period 1975-1990. We reassessed morphological distinctness with new measurements and added several analyses of genetic distinctness based on mitochondrial and nuclear sequence markers, as well as AFLP fingerprinting and SNPs mined from RAD sequences. The Isterfoss population is shown to be most closely related to its geographical neighbors, yet clearly morphologically and genetically distinct and homogeneous. We conclude that this population is in the process of sympatric speciation, with temporal isolation being the most important direct barrier to gene flow. The shift in reproductive season results from the particular temperature and water level regime in the Isterfoss rapids. The distinct adult body shape and loss of flight are hypothesized to be an adaptation to the unusual habitat. Ecological diversification on small spatial and temporal scales is one of the likely causes of the high diversity of aquatic insects.

Taxonomic revision of Gelidium tsengii and Gelidium honghaiwanense sp. nov. (Gelidiales, Rhodophyta) from China based upon molecular and morphological data analyses

NASA Astrophysics Data System (ADS)

Wang, Xulei; Xia, Bangmei; Bottalico, Antonella; Wang, Guangce

2017-11-01

The taxonomic relationship of Chinese Gelidium tsengii and Gelidium johnstonii was ambiguous. For almost 20 years they have been regarded as distinct taxa and until 2002 G. johnstonii was considered as a misapplied name of G. tsengii. In this study, herbarium specimens that initially attributed to G. tsengii and fresh G. tsengii specimens were used to address the taxonomic issues. In phylogenetic studies, G. tsengii from Dayawan, China, near the type locality of G. tsengii and G. johnstonii from Sonora, Mexico, the type locality of G. johnstonii, formed a monophyletic group with maximum support in rbcL and COI genes analyses, indicating that they were genetically identical. In morphological studies, G. tsengii was similar to G. johnstonii in branching pattern, inner structures and fructiferous organs. Consequently, we considered that semi-circular outline of G. tsengii could no longer be treated as a discrimating feature. G. johnstonii had priority of publication and according to the International Code of Botanical Nomenclature, G. tsengii was proposed as a synonym of G. johnstonii. Gelidium honghaiwanense sp. nov. was described from Guangdong, China on the basis of morphological and molecular data. For vegetative structures, it was characterized by flattened upright frond, regular two-three times branches pinnate or alternate and clavate ultimate branchlets. For reproductive structures, the tetrasporangial sori were in the apical part of branches and the tetrasporangial branchlets were distichously distributed along second order branches. The present study clarified the relationship between G. tsengii and G. johnstonii from Guangdong and added a new Gelidium species to the Chinese algal flora.

Analysis of Multilayer Devices for Superconducting Electronics by High-Resolution Scanning Transmission Electron Microscopy and Energy Dispersive Spectroscopy

DOE PAGES

Missert, Nancy; Kotula, Paul G.; Rye, Michael; ...

2017-02-15

We used a focused ion beam to obtain cross-sectional specimens from both magnetic multilayer and Nb/Al-AlOx/Nb Josephson junction devices for characterization by scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDX). An automated multivariate statistical analysis of the EDX spectral images produced chemically unique component images of individual layers within the multilayer structures. STEM imaging elucidated distinct variations in film morphology, interface quality, and/or etch artifacts that could be correlated to magnetic and/or electrical properties measured on the same devices.

Raman, AFM and SNOM high resolution imaging of carotene crystals in a model carrot cell system.

PubMed

Rygula, Anna; Oleszkiewicz, Tomasz; Grzebelus, Ewa; Pacia, Marta Z; Baranska, Malgorzata; Baranski, Rafal

2018-05-15

Three non-destructive and complementary techniques, Raman imaging, Atomic Force Microscopy and Scanning Near-field Optical Microscopy were used simultaneously to show for the first time chemical and structural differences of carotenoid crystals. Spectroscopic and microscopic scanning probe measurements were applied to the released crystals or to crystals accumulated in a unique, carotenoids rich callus tissue growing in vitro that is considered as a new model system for plant carotenoid research. Three distinct morphological crystal types of various carotenoid composition were identified, a needle-like, rhomboidal and helical. Raman imaging using 532 and 488 nm excitation lines provided evidence that the needle-like and rhomboidal crystals had similar carotenoid composition and that they were composed mainly of β-carotene accompanied by α-carotene. However, the presence of α-carotene was not identified in the helical crystals, which had the characteristic spatial structure. AFM measurements of crystals identified by Raman imaging revealed the crystal topography and showed the needle-like and rhomboidal crystals were planar but they differed in all three dimensions. Combining SNOM and Raman imaging enabled indication of carotenoid rich structures and visualised their distribution in the cell. The morphology of identified subcellular structures was characteristic for crystalline, membraneous and tubular chromoplasts that are plant organelles responsible for carotenoid accumulation in cells. Copyright © 2018 Elsevier B.V. All rights reserved.

Population genetic structure in migratory sandhill cranes and the role of Pleistocene glaciations.

PubMed

Jones, Kenneth L; Krapu, Gary L; Brandt, David A; Ashley, Mary V

2005-08-01

Previous studies of migratory sandhill cranes (Grus canadensis) have made significant progress explaining evolution of this group at the species scale, but have been unsuccessful in explaining the geographically partitioned variation in morphology seen on the population scale. The objectives of this study were to assess the population structure and gene flow patterns among migratory sandhill cranes using microsatellite DNA genotypes and mitochondrial DNA haplotypes of a large sample of individuals across three populations. In particular, we were interested in evaluating the roles of Pleistocene glaciation events and postglaciation gene flow in shaping the present-day population structure. Our results indicate substantial gene flow across regions of the Midcontinental population that are geographically adjacent, suggesting that gene flow for most of the region follows an isolation-by-distance model. Male-mediated gene flow and strong female philopatry may explain the differing patterns of nuclear and mitochondrial variation. Taken in context with precise geographical information on breeding locations, the morphologic and microsatellite DNA variation shows a gradation from the Arctic-nesting subspecies G. c. canadensis to the nonArctic subspecies G. c. tabida. Analogous to other Arctic-nesting birds, it is probable that the population structure seen in Midcontinental sandhill cranes reflects the result of postglacial secondary contact. Our data suggest that subspecies of migratory sandhills experience significant gene flow and therefore do not represent distinct and independent genetic entities.

Revealing Anisotropic Spinel Formation on Pristine Li- and Mn-Rich Layered Oxide Surface and Its Impact on Cathode Performance

DOE PAGES

Kuppan, Saravanan; Shukla, Alpesh Khushalchand; Membreno, Daniel; ...

2017-01-06

Surface properties of cathode particles play important roles in the transport of ions and electrons and they may ultimately dominate cathode's performance and stability in lithium-ion batteries. Through the use of carefully prepared Li 1.2Ni 0.13Mn 0.54Co 0.13O 2 crystal samples with six distinct morphologies, surface transition-metal redox activities and crystal structural transformation are investigated as a function of surface area and surface crystalline orientation. Complementary depth-profiled core-level spectroscopy, namely, X-ray absorption spectroscopy, electron energy loss spectroscopy, and atomic-resolution scanning transmission electron microscopy, are applied in the study, presenting a fine example of combining advanced diagnostic techniques with a well-definedmore » model system of battery materials. Here, we report the following findings: (1) a thin layer of defective spinel with reduced transition metals, similar to what is reported on cycled conventional secondary particles in the literature, is found on pristine oxide surface even before cycling, and (2) surface crystal structure and chemical composition of both pristine and cycled particles are facet dependent. Oxide structural and cycling stabilities improve with maximum expression of surface facets stable against transition-metal reduction. Finally, the intricate relationships among morphology, surface reactivity and structural transformation, electrochemical performance, and stability of the cathode materials are revealed.« less

Metal-ion interactions and the structural organization of Sepia eumelanin.

PubMed

Liu, Yan; Simon, John D

2005-02-01

The structural organization of melanin granules isolated from ink sacs of Sepia officinalis was examined as a function of metal ion content by scanning electron microscopy and atomic force microscopy. Exposing Sepia melanin granules to ethelenediaminetetraacetic acid (EDTA) solution or to metal salt solutions changed the metal content in the melanin, but did not alter granular morphology. Thus ionic forces between the organic components and metal ions in melanin are not required to sustain the natural morphology once the granule is assembled. However, when aqueous suspensions of Sepia melanin granules of varying metal content are ultra-sonicated, EDTA-washed and Fe-saturated melanin samples lose material to the solution more readily than the corresponding Ca(II) and Mg(II)-loaded samples. The solubilized components are found to be 5,6-dihydroxyindole-2-carboxylic acid (DHICA)-rich constituents. Associated with different metal ions, Na(I), Ca(II) and Mg(II) or Fe(III), these DHICA-rich entities form distinct two-dimensional aggregation structures when dried on the flat surface of mica. The data suggest multiply-charged ions play an important role in assisting or templating the assembly of the metal-free organic components to form the three-dimensional substructure distributed along the protein scaffold within the granule.

Numerical Simulations of Silverpit Crater Collapse

NASA Technical Reports Server (NTRS)

Collins, G. S.; Turtle, E. P.; Melosh, H. J.

2003-01-01

The Silverpit crater is a recently discovered, 60-65 Myr old complex crater, which lies buried beneath the North Sea, about 150 km east of Britain. High-resolution images of Silverpit's subsurface structure, provided by three-dimensional seismic reflection data, reveal an inner-crater morphology similar to that expected for a 5-8 km diameter terrestrial crater. The crater walls show evidence of terracestyle slumping and there is a distinct central uplift, which may have produced a central peak in the pristine crater morphology. However, Silverpit is not a typical 5-km diameter terrestrial crater, because it exhibits multiple, concentric rings outside the main cavity. External concentric rings are normally associated with much larger impact structures, for example Chicxulub on Earth, or Orientale on the Moon. Furthermore, external rings associated with large impacts on the terrestrial planets and moons are widely-spaced, predominantly inwardly-facing, asymmetric scarps. However, the seismic data show that the external rings at Silverpit represent closely-spaced, concentric fault-bound graben, with both inwardly and outwardly facing faults-carps. This type of multi-ring structure is directly analogous to the Valhalla-type multi-ring basins found on the icy satellites. Thus, the presence and style of the multiple rings at Silverpit is surprising given both the size of the crater and its planetary setting.

Otolith morphology varies between populations, sexes and male alternative reproductive tactics in a vocal toadfish Porichthys notatus.

PubMed

Bose, A P H; Adragna, J B; Balshine, S

2017-01-01

In this study, the morphology of sagittal otoliths of the plainfin midshipman fish Porichthys notatus was compared between populations, sexes and male alternative reproductive phenotypes (known as 'type I males or guarders' and 'type II males or sneakers'). Sagitta size increased with P. notatus size and changes in shape were also detected with increasing body size. Porichthys notatus sagittae begin as simple rounded structures, but then elongate as they grow and take on a more triangular and complex shape with several prominent notches and indentations along the dorsal and caudal edges. Moreover, the sagittae of the two geographically and genetically distinct populations of P. notatus (northern and southern) differed in shape. Porichthys notatus from the north possessed taller sagittae with deeper caudal indentations compared to P. notatus from the south. Sagitta shape also differed between females and males of the conventional guarder tactic. Furthermore, guarder males had smaller sagittae for their body size than did sneaker males or females. These differences in sagittal otolith morphology are discussed in relation to ecological and life history differences between the sexes and male tactics of this species. This is the first study to investigate teleost otolith morphology from the perspective of alternative reproductive tactics. © 2016 The Fisheries Society of the British Isles.

Controlling the morphology and performance of FO membrane via adjusting the atmosphere humidity during casting procedure

NASA Astrophysics Data System (ADS)

Zuo, Hao-Ran; Cao, Gui-Ping; Wang, Meng; Zhang, Huan-Huan; Song, Chen-Chen; Fang, Xu; Wang, Tao

2018-03-01

Forward osmosis (FO) has received great interest for its considerable potential in a wide range of fields. In this work, the morphology and performance of FO membrane were regulated by adjusting the atmosphere humidity (HC) of casting procedure. The polysulfone support layer was casted under various atmosphere humidity levels ranging from 40% to 80%. By multi-techniques such as SEM, AFM, and XPS, it was proved that the atmosphere humidity had modified the surface morphology and thickness of the skin layer in support layer, which contributed up to 90% of the structure parameter, resulting in distinct morphology, thickness, and cross-linking degree of active layer. The active layer with sparse bead-like wrinkles on the smooth surface of support layer casted at HC = 65% showed the highest water permeability [26.9 (L/m2 h MPa)] and considerable low salt permeability [0.0390 (L/m2 h)]. It was found that the water flux of FO-65 was 27% and 46% higher than that of FO-80 in AL-DS and AL-FS mode, respectively, and the salt rejection was as high as 98%. Our work highlighted the importance of considering the effect of atmosphere humidity during casting when design an FO membrane for appropriate performance.

Endodontic treatment of a mandibular second premolar with three root canals.

PubMed

Aguiar, Carlos; Mendes, Daniela; Câmara, Andréa; Figueiredo, Jose

2010-03-01

The purpose of this case report is to describe a nonsurgical endodontic treatment of a mandibular left second premolar with two separate roots and three distinct root canals. In endodontics, the possible existence of extra canals must be considered before endodontic treatment is instituted. A wide morphological variation of the root canal system is known to exist. A 36-year-old male patient was referred for endodontic treatment on the left mandibular second premolar. Radiographic examination of the involved tooth revealed an unusual, complex root canal anatomy. There was an irregular root morphology consisting of two distinct roots and three canals. This case report describes the successful nonsurgical endodontic treatment of a mandibular left second premolar with two separate roots and three distinct root canals filled using size 35 Thermafil gutta-percha carriers and AH Plus sealer. On the one-year follow-up radiograph, the tooth was asymptomatic, confirming adequate healing with no complications. Even in a tooth with an extremely complex root canal morphology, conventional endodontic treatment without surgical intervention can result in adequate healing without any complications.

Pelagia benovici sp. nov. (Cnidaria, Scyphozoa): a new jellyfish in the Mediterranean Sea.

PubMed

Piraino, Stefano; Aglieri, Giorgio; Martell, Luis; Mazzoldi, Carlotta; Melli, Valentina; Milisenda, Giacomo; Scorrano, Simonetta; Boero, Ferdinando

2014-05-07

A bloom of an unknown semaestome jellyfish species was recorded in the North Adriatic Sea from September 2013 to early 2014. Morphological analysis of several specimens showed distinct differences from other known semaestome species in the Mediterranean Sea and unquestionably identified them as belonging to a new pelagiid species within genus Pelagia. The new species is morphologically distinct from P. noctiluca, currently the only recognized valid species in the genus, and from other doubtful Pelagia species recorded from other areas of the world. Molecular analyses of mitochondrial cytochrome c oxidase subunit I (COI) and nuclear 28S ribosomal DNA genes corroborate its specific distinction from P. noctiluca and other pelagiid taxa, supporting the monophyly of Pelagiidae. Thus, we describe Pelagia benovici sp. nov. Piraino, Aglieri, Scorrano & Boero.

Boosting electrical conductivity in a gel-derived material by nanostructuring with trace carbon nanotubes

NASA Astrophysics Data System (ADS)

Canevet, David; Pérez Del Pino, Angel; Amabilino, David B.; Sallé, Marc

2011-07-01

An organogelator with two distinct π-functional units is able to incorporate carbon nanotubes into its mesh of fibres in the gel state. The morphology of the material derived from this nanocomposite after evaporation of the solvent is a complex mesh of fibres which is clearly different from the pure gelator. This feature indicates a role of the nanotubes in assisting the formation of a fibre structure in the gel thanks to their interaction with the pyrene units in the organogelator. The nanocomposite conducts electricity once the p-type gelator is doped with iodine vapour. The change in morphology caused by the carbon material increases the conductivity of the material compared with the purely organic conducting system. It is remarkable that this improvement in the physical property is caused by an extremely small proportion of the carbon material (only present at a ratio of 0.1% w/w). The practically unique properties of TTF unit allow measurements with both doped and undoped materials with conducting atomic force microscopy which have demonstrated that the carbon nanotubes are not directly responsible for the increased conductivity.An organogelator with two distinct π-functional units is able to incorporate carbon nanotubes into its mesh of fibres in the gel state. The morphology of the material derived from this nanocomposite after evaporation of the solvent is a complex mesh of fibres which is clearly different from the pure gelator. This feature indicates a role of the nanotubes in assisting the formation of a fibre structure in the gel thanks to their interaction with the pyrene units in the organogelator. The nanocomposite conducts electricity once the p-type gelator is doped with iodine vapour. The change in morphology caused by the carbon material increases the conductivity of the material compared with the purely organic conducting system. It is remarkable that this improvement in the physical property is caused by an extremely small proportion of the carbon material (only present at a ratio of 0.1% w/w). The practically unique properties of TTF unit allow measurements with both doped and undoped materials with conducting atomic force microscopy which have demonstrated that the carbon nanotubes are not directly responsible for the increased conductivity. Electronic supplementary information (ESI) available: Details concerning the preparation of 1-SWCNTs composite. See DOI: 10.1039/c1nr10235d

Leptospira interrogans causes quantitative and morphological disturbances in adherens junctions and other biological groups of proteins in human endothelial cells

PubMed Central

Sato, Hiromi

2017-01-01

Pathogenic Leptospira transmits from animals to humans, causing the zoonotic life-threatening infection called leptospirosis. This infection is reported worldwide with higher risk in tropical regions. Symptoms of leptospirosis range from mild illness to severe illness such as liver damage, kidney failure, respiratory distress, meningitis, and fatal hemorrhagic disease. Invasive species of Leptospira rapidly disseminate to multiple tissues where this bacterium damages host endothelial cells, increasing vascular permeability. Despite the burden in humans and animals, the pathogenic mechanisms of Leptospira infection remain to be elucidated. The pathogenic leptospires adhere to endothelial cells and permeabilize endothelial barriers in vivo and in vitro. In this study, human endothelial cells were infected with the pathogenic L. interrogans serovar Copenhageni or the saprophyte L. biflexa serovar Patoc to investigate morphological changes and other distinctive phenotypes of host cell proteins by fluorescence microscopy. Among those analyzed, 17 proteins from five biological classes demonstrated distinctive phenotypes in morphology and/or signal intensity upon infection with Leptospira. The affected biological groups include: 1) extracellular matrix, 2) intercellular adhesion molecules and cell surface receptors, 3) intracellular proteins, 4) cell-cell junction proteins, and 5) a cytoskeletal protein. Infection with the pathogenic strain most profoundly disturbed the biological structures of adherens junctions (VE-cadherin and catenins) and actin filaments. Our data illuminate morphological disruptions and reduced signals of cell-cell junction proteins and filamentous actin in L. interrogans-infected endothelial cells. In addition, Leptospira infection, regardless of pathogenic status, influenced other host proteins belonging to multiple biological classes. Our data suggest that this zoonotic agent may damage endothelial cells via multiple cascades or pathways including endothelial barrier damage and inflammation, potentially leading to vascular hyperpermeability and severe illness in vivo. This work provides new insights into the pathophysiological mechanisms of Leptospira infection. PMID:28750011

Leptospira interrogans causes quantitative and morphological disturbances in adherens junctions and other biological groups of proteins in human endothelial cells.

PubMed

Sato, Hiromi; Coburn, Jenifer

2017-07-01

Pathogenic Leptospira transmits from animals to humans, causing the zoonotic life-threatening infection called leptospirosis. This infection is reported worldwide with higher risk in tropical regions. Symptoms of leptospirosis range from mild illness to severe illness such as liver damage, kidney failure, respiratory distress, meningitis, and fatal hemorrhagic disease. Invasive species of Leptospira rapidly disseminate to multiple tissues where this bacterium damages host endothelial cells, increasing vascular permeability. Despite the burden in humans and animals, the pathogenic mechanisms of Leptospira infection remain to be elucidated. The pathogenic leptospires adhere to endothelial cells and permeabilize endothelial barriers in vivo and in vitro. In this study, human endothelial cells were infected with the pathogenic L. interrogans serovar Copenhageni or the saprophyte L. biflexa serovar Patoc to investigate morphological changes and other distinctive phenotypes of host cell proteins by fluorescence microscopy. Among those analyzed, 17 proteins from five biological classes demonstrated distinctive phenotypes in morphology and/or signal intensity upon infection with Leptospira. The affected biological groups include: 1) extracellular matrix, 2) intercellular adhesion molecules and cell surface receptors, 3) intracellular proteins, 4) cell-cell junction proteins, and 5) a cytoskeletal protein. Infection with the pathogenic strain most profoundly disturbed the biological structures of adherens junctions (VE-cadherin and catenins) and actin filaments. Our data illuminate morphological disruptions and reduced signals of cell-cell junction proteins and filamentous actin in L. interrogans-infected endothelial cells. In addition, Leptospira infection, regardless of pathogenic status, influenced other host proteins belonging to multiple biological classes. Our data suggest that this zoonotic agent may damage endothelial cells via multiple cascades or pathways including endothelial barrier damage and inflammation, potentially leading to vascular hyperpermeability and severe illness in vivo. This work provides new insights into the pathophysiological mechanisms of Leptospira infection.

Design of nano- and microfiber combined scaffolds by electrospinning of collagen onto starch-based fiber meshes: a man-made equivalent of natural extracellular matrix.

PubMed

Tuzlakoglu, Kadriye; Santos, Marina I; Neves, Nuno; Reis, Rui L

2011-02-01

Mimicking the structural organization and biologic function of natural extracellular matrix has been one of the main goals of tissue engineering. Nevertheless, the majority of scaffolding materials for bone regeneration highlights biochemical functionality in detriment of mechanical properties. In this work we present a rather innovative construct that combines in the same structure electrospun type I collagen nanofibers with starch-based microfibers. These combined structures were obtained by a two-step methodology and structurally consist in a type I collagen nano-network incorporated on a macro starch-based support. The morphology of the developed structures was assessed by several microscopy techniques and the collagenous nature of the nano-network was confirmed by immunohistochemistry. In addition, and especially regarding the requirements of large bone defects, we also successfully introduced the concept of layer by layer, as a way to produce thicker structures. In an attempt to recreate bone microenvironment, the design and biochemical composition of the combined structures also envisioned bone-forming cells and endothelial cells (ECs). The inclusion of a type I collagen nano-network induced a stretched morphology and improved the metabolic activity of osteoblasts. Regarding ECs, the presence of type I collagen on the combined structures provided adhesive support and obviated the need of precoating with fibronectin. It was also importantly observed that ECs on the nano-network organized into circular structures, a three-dimensional arrangement distinct from that observed for osteoblasts and resembling the microcappillary-like organizations formed during angiogenesis. By providing simultaneously physical and chemical cues for cells, the herein-proposed combined structures hold a great potential in bone regeneration as a man-made equivalent of extracellular matrix.

Volitional Weight-Lifting in Rats Promotes Adaptation via Performance and Muscle Morphology prior to Gains in Muscle Mass

PubMed Central

Rader, Erik P; Miller, G Roger; Chetlin, Robert D; Wirth, Oliver; Baker, Brent A

2014-01-01

Investigation of volitional animal models of resistance training has been instrumental in our understanding of adaptive training. However, these studies have lacked reactive force measurements, a precise performance measure, and morphological analysis at a distinct phase of training – when initial strength gains precede muscle hypertrophy. Our aim was to expose rats to one month of training (70 or 700 g load) on a custom-designed weight-lifting apparatus for analysis of reactive forces and muscle morphology prior to muscle hypertrophy. Exclusively following 700 g load training, forces increased by 21% whereas muscle masses remained unaltered. For soleus (SOL) and tibialis anterior (TA) muscles, 700 g load training increased muscle fiber number per unit area by ∼20% and decreased muscle fiber area by ∼20%. Additionally, number of muscle fibers per section increased by 18% for SOL muscles. These results establish that distinct morphological alterations accompany early strength gains in a volitional animal model of load-dependent adaptive resistance training. PMID:25392697

The morphologies of breast cancer cell lines in three-dimensionalassays correlate with their profiles of gene expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kenny, Paraic A.; Lee, Genee Y.; Myers, Connie A.

2007-01-31

3D cell cultures are rapidly becoming the method of choice for the physiologically relevant modeling of many aspects of non-malignant and malignant cell behavior ex vivo. Nevertheless, only a limited number of distinct cell types have been evaluated in this assay to date. Here we report the first large scale comparison of the transcriptional profiles and 3D cell culture phenotypes of a substantial panel of human breast cancer cell lines. Each cell line adopts a colony morphology of one of four main classes in 3D culture. These morphologies reflect, at least in part, the underlying gene expression profile and proteinmore » expression patterns of the cell lines, and distinct morphologies were also associated with tumor cell invasiveness and with cell lines originating from metastases. We further demonstrate that consistent differences in genes encoding signal transduction proteins emerge when even tumor cells are cultured in 3D microenvironments.« less

Pavilion Lake, British Columbia, Canada - An investigation of potentially unique freshwater microbialites, and their application to Mars exploration.

NASA Astrophysics Data System (ADS)

Lim, D. S.; Laval, B.; Slater, G.; Andersen, D.; Airo, A.; Mullins, G.; Schulze-Makuch, D.; Cady, S.; McKay, C.

2005-12-01

Pavilion Lake, B. C., Canada has become the first target site of an on-going NASA effort to investigate the Mars analogue potential of terrestrial lacustrine carbonates. A combination of hypothesis and exploration driven research activities are underway to study the unusual freshwater microbialite structures found in this lake. These structures are of interest in terms of models of Precambrian reefs and may also be relevant to carbonate formation in ancient lakes on Mars. Laval et al. (2000) provides an overview of the morphological characteristics of the microbialites, and explores the physical limnology of Pavilion Lake. Several key hypotheses and questions related to the role of biology in the formation of the microbialites, and the effect of varying light levels on the microbialite morphologies have since resulted from Laval et al., but to date remain unanswered. In August 2004, the Pavilion Lake Research Project (PLRP) was established to commence a new round of investigations into Pavilion Lake, to test hypotheses concerning the factors controlling carbonate formation, and to collect further exploration data related to understanding the lake's limnology and development. Laval et al. classified the differing microbialite structures into four depth categories: shallow to intermediate (5-10m), intermediate (~20m), intermediate to deep (20-30m), and deep facies (30-35m). There is a variation of the morphology and mechanical strength of the structures with depth, which may reflect a change in the relative role of biotic and non-biotic precipitation with lowering light levels. Recent field investigations (August 2005) revealed carbonate structures at depths beyond what was reported in Laval et al. (2000). These new structures appear at 46-55m, and are morphologically distinct from the previously described microbialites. Here we present our current research activities at Pavilion Lake, along with recent data collection results. Excursions to the lake have included the use of SCUBA to sample collect and to install a variety of sensors including a thermistor chain and a Licor light meter. Seepage meters have also been placed in strategic regions of the lake to collect incoming lake groundwater for future chemical limnological analyses and hydrological mapping of the area. In addition, conventional Conductivity/Temperature/Depth (CTD) profiles and water sampling has been conducted during a winter and summer period, and will be presented here. Microbialite samples recovered from each of the discernible morphological depth transects have been investigated for relative variations in d13C isotopic signatures, and the results will presented here.

Structure-mechanics relationships in mineralized tendons.

PubMed

Spiesz, Ewa M; Zysset, Philippe K

2015-12-01

In this paper, we review the hierarchical structure and the resulting elastic properties of mineralized tendons as obtained by various multiscale experimental and computational methods spanning from nano- to macroscale. The mechanical properties of mineralized collagen fibres are important to understand the mechanics of hard tissues constituted by complex arrangements of these fibres, like in human lamellar bone. The uniaxial mineralized collagen fibre array naturally occurring in avian tendons is a well studied model tissue for investigating various stages of tissue mineralization and the corresponding elastic properties. Some avian tendons mineralize with maturation, which results in a graded structure containing two zones of distinct morphology, circumferential and interstitial. These zones exhibit different amounts of mineral, collagen, pores and a different mineral distribution between collagen fibrillar and extrafibrillar space that lead to distinct elastic properties. Mineralized tendon cells have two phenotypes: elongated tenocytes placed between fibres in the circumferential zone and cuboidal cells with lower aspect ratios in the interstitial zone. Interestingly some regions of avian tendons seem to be predestined to mineralization, which is exhibited as specific collagen cross-linking patterns as well as distribution of minor tendon constituents (like proteoglycans) and loss of collagen crimp. Results of investigations in naturally mineralizing avian tendons may be useful in understanding the pathological mineralization occurring in some human tendons. Copyright © 2015 Elsevier Ltd. All rights reserved.

A small molecule-based strategy for endothelial differentiation and three-dimensional morphogenesis from human embryonic stem cells.

PubMed

Geng, Yijie; Feng, Bradley

2016-07-01

The emerging models of human embryonic stem cell (hESC) self-organizing organoids provide a valuable in vitro platform for studying self-organizing processes that presumably mimic in vivo human developmental events. Here we report that through a chemical screen, we identified two novel and structurally similar small molecules BIR1 and BIR2 which robustly induced the self-organization of a balloon-shaped three-dimensional structure when applied to two-dimensional adherent hESC cultures in the absence of growth factors. Gene expression analyses and functional assays demonstrated an endothelial identity of this balloon-like structure, while cell surface marker analyses revealed a VE-cadherin(+)CD31(+)CD34(+)KDR(+)CD43(-) putative endothelial progenitor population. Furthermore, molecular marker labeling and morphological examinations characterized several other distinct DiI-Ac-LDL(+) multi-cellular modules and a VEGFR3(+) sprouting structure in the balloon cultures that likely represented intermediate structures of balloon-formation.

MC carbide structures in M(lc2)ar-M247. M.S. Thesis - Final Report

NASA Technical Reports Server (NTRS)

Wawro, S. W.

1982-01-01

The morphologies and distribution of the MC carbides in Mar-M247 ingot stock and castings were investigated using metallographic, X-ray diffraction and energy-dispersive X-ray analysis techniques. The MC carbides were found to form script structures during solidification. The script structures were composed of three distinct parts. The central cores and elongated arms of the MC carbide script structures had compositions (Ti, Cr, Hf, Ta, W)C and lattice parameters of 4.39 A. The elongated script arms terminated in enlarged, angular "heads". The heads had compositions (Ti, Hf, Ta, W)C and lattice parameters of approximately 4.50 A. The heads had a higher Hf content than the cores and arms. The size of the script structures, as well as the relative amount of head-type to core and arm-type MC carbide, was found to be determined by solidification conditions. No carryover of the MC carbides from the ingot stock to the remelted and cast material was observed.

The gyri of the octopus vertical lobe have distinct neurochemical identities.

PubMed

Shigeno, Shuichi; Ragsdale, Clifton W

2015-06-15

The cephalopod vertical lobe is the largest learning and memory structure known in invertebrate nervous systems. It is part of the visual learning circuit of the central brain, which also includes the superior frontal and subvertical lobes. Despite the well-established functional importance of this system, little is known about neuropil organization of these structures and there is to date no evidence that the five longitudinal gyri of the vertical lobe, perhaps the most distinctive morphological feature of the octopus brain, differ in their connections or molecular identities. We studied the histochemical organization of these structures in hatchling and adult Octopus bimaculoides brains with immunostaining for serotonin, octopus gonadotropin-releasing hormone (oGNRH), and octopressin-neurophysin (OP-NP). Our major finding is that the five lobules forming the vertical lobe gyri have distinct neurochemical signatures. This is most prominent in the hatchling brain, where the median and mediolateral lobules are enriched in OP-NP fibers, the lateral lobule is marked by oGNRH innervation, and serotonin immunostaining heavily labels the median and lateral lobules. A major source of input to the vertical lobe is the superior frontal lobe, which is dominated by a neuropil of interweaving fiber bundles. We have found that this neuropil also has an intrinsic neurochemical organization: it is partitioned into territories alternately enriched or impoverished in oGNRH-containing fascicles. Our findings establish that the constituent lobes of the octopus superior frontal-vertical system have an intricate internal anatomy, one likely to reflect the presence of functional subsystems within cephalopod learning circuitry. © 2015 Wiley Periodicals, Inc.

Discovery of large conical stromatolites in Lake Untersee, Antarctica.

PubMed

Andersen, D T; Sumner, D Y; Hawes, I; Webster-Brown, J; McKay, C P

2011-05-01

Lake Untersee is one of the largest (11.4 km(2)) and deepest (>160 m) freshwater lakes in East Antarctica. Located at 71°S the lake has a perennial ice cover, a water column that, with the exception of a small anoxic basin in the southwest of the lake, is well mixed, supersaturated with dissolved oxygen, alkaline (pH 10.4) and exceedingly clear. The floor of the lake is covered with photosynthetic microbial mats to depths of at least 100 m. These mats are primarily composed of filamentous cyanophytes and form two distinct macroscopic structures, one of which--cm-scale cuspate pinnacles dominated by Leptolyngbya spp.--is common in Antarctica, but the second--laminated, conical stromatolites that rise up to 0.5 m above the lake floor, dominated by Phormidium spp.--has not previously been reported in any modern environment. The laminae that form the conical stromatolites are 0.2-0.8 mm in thickness consisting of fine clays and organic material; carbon dating implies that laminations may occur on near decadal timescales. The uniformly steep sides (59.6 ± 2.5°) and the regular laminar structure of the cones suggest that they may provide a modern analog for growth of some of the oldest well-described Archean stromatolites. Mechanisms underlying the formation of these stromatolites are as yet unclear, but their growth is distinct from that of the cuspate pinnacles. The sympatric occurrence of pinnacles and cones related to microbial communities with distinct cyanobacterial compositions suggest that specific microbial behaviors underpin the morphological differences in the structures. © 2011 Blackwell Publishing Ltd.

Computation of Semantic Number from Morphological Information

ERIC Educational Resources Information Center

Berent, Iris; Pinker, Steven; Tzelgov, Joseph; Bibi, Uri; Goldfarb, Liat

2005-01-01

The distinction between singular and plural enters into linguistic phenomena such as morphology, lexical semantics, and agreement and also must interface with perceptual and conceptual systems that assess numerosity in the world. Three experiments examine the computation of semantic number for singulars and plurals from the morphological…

Large Impact Features on Europa: Results of the Galileo Nominal Mission

NASA Technical Reports Server (NTRS)

Moore, Jeffrey M.; Asphaug, Erik; Sullivan, Robert J.; Klemaszewski, James E.; Bender, Kelly C.; Greeley, Ronald; Geissler, Paul E.; McEwen, Alfred S.; Turtle, Elizabeth P.; Phillips, Cynthia B.

1998-01-01

The Galileo Orbiter examined several impact features on Europa at considerably better resolution than was possible from Voyager. The new data allow us to describe the morphology and infer the geology of the largest impact features on Europa, which are probes into the crust. We observe two basic types of large impact features: (1) "classic" impact craters that grossly resemble well-preserved lunar craters of similar size but are more topographically subdued (e.g., Pwyll) and (2) very flat circular features that lack the basic topographic structures of impact craters such as raised rims, a central depression, or central peaks, and which largely owe their identification as impact features to the field of secondary craters radially sprayed about them (e.g., Callanish). Our interpretation is that the classic craters (all <30 km diameter) formed entirely within a solid target at least 5 to 10 km thick that exhibited brittle behavior on time scales of the impact events. Some of the classic craters have a more subdued topography than fresh craters of similar size on other icy bodies such as Ganymede and Callisto, probably due to the enhanced viscous relaxation produced by a steeper thermal gradient on Europa. Pedestal ejecta facies on Europa (and Ganymede) may be produced by the relief-flattening movement of plastically deforming but otherwise solid ice that was warm at the time of emplacement. Callanish and Tyre do not appear to be larger and even more viscously relaxed versions of the classic craters; rather they display totally different morphologies such as distinctive textures and a series of large concentric structural rings cutting impact-feature-related materials. Impact simulations suggest that the distinctive morphologies would not be produced by impact into a solid ice target, but may be explained by impact into an ice layer approximately 10 to 15 km thick overlying a low-viscosity material such as water. The very wide (near antipodal) separation of Callanish and Tyre imply that approximately 10-15 km may have been the global average thickness of the rigid crust of Europa when these impacts occurred. The absence of detectable craters superposed on the interior deposits of Callanish suggests that it is geologically young (< 10(exp 8) years). Hence, it seems likely that our preliminary conclusions about the subsurface structure of Europa apply to the current day.

Large Impact Features on Europa: Results of the Galileo Nominal Mission

USGS Publications Warehouse

Moore, Johnnie N.; Asphaug, E.; Sullivan, R.J.; Klemaszewski, J.E.; Bender, K.C.; Greeley, R.; Geissler, P.E.; McEwen, A.S.; Turtle, E.P.; Phillips, C.B.; Tufts, B.R.; Head, J. W.; Pappalardo, R.T.; Jones, K.B.; Chapman, C.R.; Belton, M.J.S.; Kirk, R.L.; Morrison, D.

1998-01-01

The Galileo Orbiter examined several impact features on Europa at considerably better resolution than was possible from Voyager. The new data allow us to describe the morphology and infer the geology of the largest impact features on Europa, which are probes into the crust. We observe two basic types of large impact features: (1) "classic" impact craters that grossly resemble well-preserved lunar craters of similar size but are more topographically subdued (e.g., Pwyll) and (2) very flat circular features that lack the basic topographic structures of impact craters such as raised rims, a central depression, or central peaks, and which largely owe their identification as impact features to the field of secondary craters radially sprayed about them (e.g., Callanish). Our interpretation is that the classic craters (all <30 km diameter) formed entirely within a solid target at least 5 to 10 km thick that exhibited brittle behavior on time scales of the impact events. Some of the classic craters have a more subdued topography than fresh craters of similar size on other icy bodies such as Ganymede and Callisto, probably due to the enhanced viscous relaxation produced by a steeper thermal gradient on Europa. Pedestal ejecta facies on Europa (and Ganymede) may be produced by the relief-flattening movement of plastically deforming but otherwise solid ice that was warm at the time of emplacement. Callanish and Tyre do not appear to be larger and even more viscously relaxed versions of the classic craters; rather they display totally different morphologies such as distinctive textures and a series of large concentric structural rings cutting impact-feature-related materials. Impact simulations suggest that the distinctive morphologies would not be produced by impact into a solid ice target, but may be explained by impact into an ice layer ~10 to 15 km thick overlying a low-viscosity material such as water. The very wide (near antipodal) separation of Callanish and Tyre imply that ~10-15 km may have been the global average thickness of the rigid crust of Europa when these impacts occurred. The absence of detectable craters superposed on the interior deposits of Callanish suggests that it is geologically young (<108years). Hence, it seems likely that our preliminary conclusions about the subsurface structure of Europa apply to the current day. ?? 1998 Academic Press.

Egg cases of the genus Apristurus (Chondrichthyes: Scyliorhinidae): phylogenetic and ecological implications.

PubMed

Flammang, Brooke E; Ebert, David A; Cailliet, Gregor M

2007-01-01

The genus Apristurus has been divided formerly into three species subgroups based on morphological and molecular phylogenies. Previous studies have agreed on the separation into distinct species groups, the largest two of which have been described as the brunneus and spongiceps groups. An examination of the egg cases produced by these oviparous catsharks corroborates the distinction in species groups: egg cases of the brunneus group have long fibrous and curly tendrils at either end, whereas egg cases of the spongiceps group lack tendrils. The egg cases of A. kampae, A. manis, A. spongiceps and Apristurus sp. D are described for the first time, and the egg cases of A. brunneus and A. riveri are re-described to include comparable morphological characteristics. The ecological implications of egg case morphology on oviposition and ventilation are also discussed.

Numerical morphology supports early number word learning: Evidence from a comparison of young Mandarin and English learners.

PubMed

Le Corre, Mathieu; Li, Peggy; Huang, Becky H; Jia, Gisela; Carey, Susan

2016-08-01

Previous studies showed that children learning a language with an obligatory singular/plural distinction (Russian and English) learn the meaning of the number word for one earlier than children learning Japanese, a language without obligatory number morphology (Barner, Libenson, Cheung, & Takasaki, 2009; Sarnecka, Kamenskaya, Yamana, Ogura, & Yudovina, 2007). This can be explained by differences in number morphology, but it can also be explained by many other differences between the languages and the environments of the children who were compared. The present study tests the hypothesis that the morphological singular/plural distinction supports the early acquisition of the meaning of the number word for one by comparing young English learners to age and SES matched young Mandarin Chinese learners. Mandarin does not have obligatory number morphology but is more similar to English than Japanese in many crucial respects. Corpus analyses show that, compared to English learners, Mandarin learners hear number words more frequently, are more likely to hear number words followed by a noun, and are more likely to hear number words in contexts where they denote a cardinal value. Two tasks show that, despite these advantages, Mandarin learners learn the meaning of the number word for one three to six months later than do English learners. These results provide the strongest evidence to date that prior knowledge of the numerical meaning of the distinction between singular and plural supports the acquisition of the meaning of the number word for one. Copyright © 2016. Published by Elsevier Inc.

Aggregation and Fibril Morphology of the Arctic Mutation of Alzheimer’s Aβ peptide by CD, TEM, STEM and in situ AFM

PubMed Central

Norlin, Nils; Hellberg, Magnus; Filippov, Andrei; Sousa, Alioscka A.; Gröbner, Gerhard; Leapman, Richard D.; Almqvist, Nils; Antzutkin, Oleg N.

2012-01-01

Morphology of aggregation intermediates, polymorphism of amyloid fibrils and aggregation kinetics of the “Arctic” mutant of the Alzheimer’s amyloid β-peptide, Aβ(1-40)(E22G), in a physiologically relevant TRIS buffer (pH 7.4) were thoroughly explored in comparison with the human wild type Alzheimer’s amyloid peptide, wt-Aβ(1-40), using both in situ atomic force and electron microscopy, circular dichroism and thioflavin T fluorescence assays. For arc-Aβ(1-40) at the end of the ‘lag’-period of fibrillization an abrupt appearance of ~3 nm size ‘spherical aggregates’ with a homogeneous morphology, was identified. Then, the aggregation proceeds with a rapid growth of amyloid fibrils with a variety of morphologies, while the spherical aggregates eventually disappeared during in situ measurements. Arc-Aβ(1-40) was also shown to form fibrils at much lower concentrations than wt-Aβ(1-40): ≤2.5 μM and 12.5 μM, respectively. Moreover, at the same concentration, 50 μM, the aggregation process proceeds more rapidly for arc-Aβ(1-40): The first amyloid fibrils were observed after ca 72 hours from the onset of incubation as compared to approximately 7 days for wt-Aβ(1-40). Amyloid fibrils of arc-Aβ(1-40) exhibit a large variety of polymorphs, at least five, both coiled and non-coiled distinct fibril structures were recognized by AFM, while at least four types of arc-Aβ(1-40) fibrils were identified by TEM and STEM and their mass-per-length statistics were collected suggesting supramolecular structures with two, four and six β-sheet laminae. Our results suggest a pathway of fibrillogenesis for full-length Alzheimer’s peptides with small and structurally ordered transient spherical aggregates as on-pathway immediate precursors of amyloid fibrils. PMID:22750418

Caught in the act: Incipient speciation across a latitudinal gradient in a semifossorial mammal from Madagascar, the mole tenrec Oryzorictes hova (Tenrecidae).

PubMed

Everson, Kathryn M; Hildebrandt, Kyndall B P; Goodman, Steven M; Olson, Link E

2018-02-28

Madagascar is one of the world's foremost biodiversity hotspots, yet a large portion of its flora and fauna remains undescribed and the driving forces of in situ diversification are not well understood. Recent studies have identified a widespread, latitudinally structured phylogeographic pattern in Madagascar's humid-forest mammals, amphibians, reptiles, and insects. Several factors may be driving this pattern, namely biogeographic barriers (i.e., rivers or valleys) or past episodes of forest contraction and expansion. In this study, we describe the phylogeographic structure of the small, semifossorial mammal Oryzorictes hova, one of Madagascar's two species of mole tenrec, found throughout Madagascar's eastern humid forest belt, from high-elevation montane forest to low-elevation forests, as well as disturbed habitat such as rice fields. Using one mitochondrial locus, four nuclear loci, and 31 craniomandibular measurements, we identified three distinct populations of O. hova associated with the northern, central, and southern regions of the island. We found little evidence of gene flow among these populations, so we treated each population as a potential species. We validated species limits using two Bayesian methods: BP&P, employing only DNA sequence data, and iBPP using both DNA and morphological data, and we assessed whether these methods are susceptible to producing false positive errors. Molecular and morphological data support the recognition of each of the three populations of O. hova as distinct species, but formal species descriptions will require additional data from type specimens. This study illustrates the importance of using integrative datasets, multiple methodological approaches, and extensive geographic sampling for species delimitation and adds evidence for a widespread phylogeographic pattern in Madagascar's humid forest taxa. Copyright © 2018 Elsevier Inc. All rights reserved.

Insulin Recruits GLUT4 from Specialized VAMP2-carrying Vesicles as well as from the Dynamic Endosomal/Trans-Golgi Network in Rat Adipocytes.

PubMed Central

Ramm, Georg; Slot, Jan Willem; James, David E.; Stoorvogel, Willem

2000-01-01

Insulin treatment of fat cells results in the translocation of the insulin-responsive glucose transporter type 4, GLUT4, from intracellular compartments to the plasma membrane. However, the precise nature of these intracellular GLUT4-carrying compartments is debated. To resolve the nature of these compartments, we have performed an extensive morphological analysis of GLUT4-containing compartments, using a novel immunocytochemical technique enabling high labeling efficiency and 3-d resolution of cytoplasmic rims isolated from rat epididymal adipocytes. In basal cells, GLUT4 was localized to three morphologically distinct intracellular structures: small vesicles, tubules, and vacuoles. In response to insulin the increase of GLUT4 at the cell surface was compensated by a decrease in small vesicles, whereas the amount in tubules and vacuoles was unchanged. Under basal conditions, many small GLUT4 positive vesicles also contained IRAP (88%) and the v-SNARE, VAMP2 (57%) but not markers of sorting endosomes (EEA1), late endosomes, or lysosomes (lgp120). A largely distinct population of GLUT4 vesicles (56%) contained the cation-dependent mannose 6-phosphate receptor (CD-MPR), a marker protein that shuttles between endosomes and the trans-Golgi network (TGN). In response to insulin, GLUT4 was recruited both from VAMP2 and CD-MPR positive vesicles. However, while the concentration of GLUT4 in the remaining VAMP2-positive vesicles was unchanged, the concentration of GLUT4 in CD-MPR-positive vesicles decreased. Taken together, we provide morphological evidence indicating that, in response to insulin, GLUT4 is recruited to the plasma membrane by fusion of preexisting VAMP2-carrying vesicles as well as by sorting from the dynamic endosomal-TGN system. PMID:11102509

Muscular anatomy of an entoproct creeping-type larva reveals extraordinary high complexity and potential shared characters with mollusks.

PubMed

Merkel, Julia; Lieb, Bernhard; Wanninger, Andreas

2015-07-03

Entoprocta (Kamptozoa) is an enigmatic, acoelomate, tentacle-bearing phylum with indirect development, either via a swimming- or a creeping-type larva and still debated phylogenetic position within Lophotrochozoa. Recent morphological and neuro-anatomical studies on the creeping-type larva support a close relationship of Entoprocta and Mollusca, with a number of shared apomorphies including a tetraneurous nervous system and a complex serotonin-expressing apical organ. However, many morphological traits of entoproct larvae, in particular of the putative basal creeping-type larva, remain elusive. Applying fluorescent markers and 3D modeling, we found that this larval type has the most complex musculature hitherto described for any lophotrochozoan larva. The muscle systems identified include numerous novel and most likely creeping-type larva-specific structures such as frontal organ retractors, several other muscle fibers originating from the frontal organ, and longitudinal prototroch muscles. Interestingly, we found distinct muscle sets that are also present in several mollusks. These include paired sets of dorso-ventral muscles that intercross ventrally above the foot sole and a paired enrolling muscle that is distinct from the musculature of the body wall. Our data add further morphological support for an entoproct-mollusk relationship (Tetraneuralia) and strongly argue for the presence of an enrolling musculature as well as seriality (but not segmentation) in the last common tetraneuralian ancestor. The evolutionary driving forces that have led to the emergence of the extraordinarily complex muscular architecture in this short-lived, non-feeding entoproct larval type remain unknown, as are the processes that give rise to the highly different and much simpler muscular bodyplan of the adult entoproct during metamorphosis.

Simultaneous covalent and noncovalent hybrid polymerizations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Z.; Tantakitti, F.; Yu, T.

Covalent and supramolecular polymers are two distinct forms of soft matter, composed of long chains of covalently and noncovalently linked structural units, respectively. We report a hybrid system formed by simultaneous covalent and supramolecular polymerizations of monomers. The process yields cylindrical fibers of uniform diameter that contain covalent and supramolecular compartments, a morphology not observed when the two polymers are formed independently. The covalent polymer has a rigid aromatic imine backbone with helicoidal conformation, and its alkylated peptide side chains are structurally identical to the monomer molecules of supramolecular polymers. In the hybrid system, covalent chains grow to higher averagemore » molar mass relative to chains formed via the same polymerization in the absence of a supramolecular compartment. The supramolecular compartments can be reversibly removed and re-formed to reconstitute the hybrid structure, suggesting soft materials with novel delivery or repair functions.« less

“FRIED EGG”: AN OCEANIC IMPACT CRATER IN THE MID-ATLANTIC?

NASA Astrophysics Data System (ADS)

Dias, F. C.; Lourenco, N.; Lobo, A.; Santos de Campos, A.; Pinto de Abreu, M.

2009-12-01

Analysis of a multibeam echosounder hydrographic survey performed in the Southern Azores Platform under the scope of the Portuguese Continental Shelf Project has revealed a large scale bathymetric structure nicknamed “Fried Egg” due to its well defined morphology. Laying at about 2km depth, this structure consists of a roughly circular 6km wide depression 110m below the surrounding ocean bottom, with a circular dome shaped central uplift 3km in diameter and with a base to top height of 300m. The associated backscatter signal presents a distinctive ring-like signature corresponding to the lower flank section of the dome, suggesting the outcrop of hard rock material. The remaining backscatter signal seems to correspond to widespread sediments. No lava flows are apparent either within the structure or on its surroundings. All these properties are compatible with the record of terrestrial impact craters, thus making of “Fried Egg” a potential oceanic impact crater.

Native structure of a type IV secretion system core complex essential for Legionella pathogenesis.

PubMed

Kubori, Tomoko; Koike, Masafumi; Bui, Xuan Thanh; Higaki, Saori; Aizawa, Shin-Ichi; Nagai, Hiroki

2014-08-12

Bacterial type IV secretion systems are evolutionarily related to conjugation systems and play a pivotal role in infection by delivering numerous virulence factors into host cells. Using transmission electron microscopy, we report the native molecular structure of the core complex of the Dot/Icm type IV secretion system encoded by Legionella pneumophila, an intracellular human pathogen. The biochemically isolated core complex, composed of at least five proteins--DotC, DotD, DotF, DotG, and DotH--has a ring-shaped structure. Intriguingly, morphologically distinct premature complexes are formed in the absence of DotG or DotF. Our data suggest that DotG forms a central channel spanning inner and outer membranes. DotF, a component dispensable for type IV secretion, plays a role in efficient embedment of DotG into the functional core complex. These results highlight a common scheme for the biogenesis of transport machinery.

Conformation-Directed Formation of Self-Healing Diblock Copolypeptide Hydrogels via Polyion Complexation.

PubMed

Sun, Yintao; Wollenberg, Alexander L; O'Shea, Timothy Mark; Cui, Yanxiang; Zhou, Z Hong; Sofroniew, Michael V; Deming, Timothy J

2017-10-25

Synthetic diblock copolypeptides were designed to incorporate oppositely charged ionic segments that form β-sheet-structured hydrogel assemblies via polyion complexation when mixed in aqueous media. The observed chain conformation directed assembly was found to be required for efficient hydrogel formation and provided distinct and useful properties to these hydrogels, including self-healing after deformation, microporous architecture, and stability against dilution in aqueous media. While many promising self-assembled materials have been prepared using disordered or liquid coacervate polyion complex (PIC) assemblies, the use of ordered chain conformations in PIC assemblies to direct formation of new supramolecular morphologies is unprecedented. The promising attributes and unique features of the β-sheet-structured PIC hydrogels described here highlight the potential of harnessing conformational order derived from PIC assembly to create new supramolecular materials.

fgfr3 and regionalization of anterior neural tube in zebrafish.

PubMed

Sleptsova-Friedrich, I; Li, Y; Emelyanov, A; Ekker, M; Korzh, V; Ge, R

2001-04-01

Here we describe the isolation of the zebrafish fgfr3 gene, its structure and chromosomal location. Expression in wild type embryos occurs in the axial mesoderm, the diencephalon, the anterior hindbrain and the anterior spinal cord. In the hindbrain, a differential expression of fgfr3 was detected at several levels of intensity, with the highest expression in the posterior rhombomere 1 that is morphologically distinct from the anterior part, which develops into the cerebellum. Further, analysis of fgfr3 expression in mutants deficient in the formation of the midbrain-hindbrain boundary (MHB), noi(-/-) and ace(-/-), demonstrated that in the absence of Pax2.1 and FGF8 activity, the expression domains of FGFR3 expand into the MHB, tegmentum, cerebellum and optic tectum, which are the affected structures in these mutants.

Spatial and temporal characteristics of flare energy release determined from X-ray and radio imaging observations

NASA Technical Reports Server (NTRS)

Hernandez, A. M.; Machado, M. E.; Vilmer, N.; Trottet, G.

1986-01-01

Using the Hard X-ray Imaging Spectrometer (HXIS) from the Solar Maximum Mission Satellite, the morphological aspects and temporal evolution of three major flares which occurred on June 29, 1980 are studied. One of these events, observed at 10:40 UT, is analyzed in particular detail, including Hard X-ray Burst Spectrometer (HXRBS) data and metric wavelength data from the Nancay radioheliograph. The flares occurred during the interaction of two distinct magnetic structures. There is an early onset phase during which there is a weak level of particle acceleration, perhaps accompanied by strong heating within the magnetic interaction region. The impulsive phase of high power energy release is associated with a major interaction between the two structures and accompanied by strong acceleration and heating.

Atomic force microscope characterization of self-assembly behaviors of cyclo[8] pyrrole on solid substrates

NASA Astrophysics Data System (ADS)

Xu, Hai; Zhao, Siqi; Xiong, Xiang; Jiang, Jinzhi; Xu, Wei; Zhu, Daoben; Zhang, Yi; Liang, Wenjie; Cai, Jianfeng

2017-04-01

Cyclo [8] pyrrole (CP) is a porphyrin analogue containing eight α-conjugated pyrrole units which are arranged in a nearly coplanar conformation. The π-π interactions between CP molecules lead to regular aggregations through a solution casting process. Using tapping mode atomic force microscope (AFM), we investigated the morphology of self-assembled aggregates formed by deposition of different CP solutions on different substrates. We found that in the n-butanol solution, nanofibrous structures could be formed on the silicon or mica surface. Interestingly, on the highly oriented pyrolytic graphite (HOPG) surface, or silicon and mica surface with a toluene solution, only irregular spherical structures were identified. The difference in the nanomorphology may be attributed to distinct interactions between molecule-molecule, molecule-solvent and molecule-substrate.

CoMIC, the hidden dynamics of mitochondrial inner compartments

PubMed Central

Cho, Bongki; Sun, Woong

2017-01-01

Mitochondria have evolutionarily, functionally and structurally distinct outer- (OMM) and inner-membranes (IMM). Thus, mitochondrial morphology is controlled by independent but coordinated activity of fission and fusion of the OMM and IMM. Constriction and division of the OMM are mediated by endocytosis-like machineries, which include dynamin-related protein 1 with additional cytosolic vesicle scissoring machineries such as actin filament and Dynamin 2. However, structural alteration of the IMM during mitochondrial division has been poorly understood. Recently, we found that the IMM and the inner compartments undergo transient and reversible constriction prior to the OMM division, which we termed CoMIC, Constriction of Mitochondrial Inner Compartment. In this short review, we further discuss the evolutionary perspective and the regulatory mechanism of CoMIC during mitochondrial division. PMID:28803609

CoMIC, the hidden dynamics of mitochondrial inner compartments.

PubMed

Cho, Bongki; Sun, Woong

2017-12-01

Mitochondria have evolutionarily, functionally and structurally distinct outer- (OMM) and inner-membranes (IMM). Thus, mitochondrial morphology is controlled by independent but coordinated activity of fission and fusion of the OMM and IMM. Constriction and division of the OMM are mediated by endocytosis-like machineries, which include dynamin-related protein 1 with additional cytosolic vesicle scissoring machineries such as actin filament and Dynamin 2. However, structural alteration of the IMM during mitochondrial division has been poorly understood. Recently, we found that the IMM and the inner compartments undergo transient and reversible constriction prior to the OMM division, which we termed CoMIC, Constriction of Mitochondrial Inner Compartment. In this short review, we further discuss the evolutionary perspective and the regulatory mechanism of CoMIC during mitochondrial division. [BMB Reports 2017; 50(12): 597-598].

Evolution of Body Elongation in Gymnophthalmid Lizards: Relationships with Climate

PubMed Central

Grizante, Mariana B.; Brandt, Renata; Kohlsdorf, Tiana

2012-01-01

The evolution of elongated body shapes in vertebrates has intrigued biologists for decades and is particularly recurrent among squamates. Several aspects might explain how the environment influences the evolution of body elongation, but climate needs to be incorporated in this scenario to evaluate how it contributes to morphological evolution. Climatic parameters include temperature and precipitation, two variables that likely influence environmental characteristics, including soil texture and substrate coverage, which may define the selective pressures acting during the evolution of morphology. Due to development of geographic information system (GIS) techniques, these variables can now be included in evolutionary biology studies and were used in the present study to test for associations between variation in body shape and climate in the tropical lizard family Gymnophthalmidae. We first investigated how the morphological traits that define body shape are correlated in these lizards and then tested for associations between a descriptor of body elongation and climate. Our analyses revealed that the evolution of body elongation in Gymnophthalmidae involved concomitant changes in different morphological traits: trunk elongation was coupled with limb shortening and a reduction in body diameter, and the gradual variation along this axis was illustrated by less-elongated morphologies exhibiting shorter trunks and longer limbs. The variation identified in Gymnophthalmidae body shape was associated with climate, with the species from more arid environments usually being more elongated. Aridity is associated with high temperatures and low precipitation, which affect additional environmental features, including the habitat structure. This feature may influence the evolution of body shape because contrasting environments likely impose distinct demands for organismal performance in several activities, such as locomotion and thermoregulation. The present study establishes a connection between morphology and a broader natural component, climate, and introduces new questions about the spatial distribution of morphological variation among squamates. PMID:23166767

Droplet sliding on inclined superhydrophobic surfaces: the effect of anisotropic contact line

NASA Astrophysics Data System (ADS)

Jiang, Youhua; Cao, Lile; Guo, Zongqi; Choi, Chang-Hwan

2017-11-01

Although the effects of solid structures on droplet retention on superhydrophobic surfaces have been studied extensively, the investigation has been restricted to the sessile droplets on horizontal surfaces where the contact line motions are axisymmetric or isotropic (either advancing or receding). In the droplet retention on inclined surfaces, the contact line motions are asymmetric or anisotropic; the advancing and receding motions coexist. In this study, we investigate the correlation between the droplet boundary pinning and the surface morphology on inclined superhydrophobic surfaces. The evolution of the droplet contact angle and width show contrary behaviors between pillar- and pore-structured surfaces due to the distinctive microscopic contact line motions. Therefore, the visualizations of the contact line motions at different locations of the boundary on inclined superhydrophobic surfaces are performed and the averaged contact line density of the boundary is quantified. The result shows that the droplet retentive force monotonously increase with the increase in contact line density, regardless of the surface morphological types, dimensions, or the direction of contact line motion (advancing, receding, or both). The result indicates that the droplet retentive force on superhydrophobic surfaces is mainly determined by the contact line density, regardless of the isotropy of the contact line.

Differences in mechanical and structural properties of surface and aerial petioles of the aquatic plant Nymphaea odorata subsp. tuberosa (Nymphaeaceae).

PubMed

Etnier, Shelley A; Villani, Philip J

2007-07-01

Lily pads (Nymphaea odorata) exhibit heterophylly where a single plant may have leaves that are submerged, floating, or above (aerial) the surface of the water. Lily pads are placed in a unique situation because each leaf form is exposed to a distinctly different set of mechanical demands. While surface petioles may be loaded in tension under conditions of wind or waves, aerial petioles are loaded in compression because they must support the weight of the lamina. Using standard techniques, we compared the mechanical and morphological properties of both surface and aerial leaf petioles. Structural stiffness (EI) and the second moment of area (I) were higher in aerial petioles, although we detected no differences in other mechanical values (elastic modulus [E], extension ratio, and breaking strength). Morphologically, aerial petioles had a thicker rind, with increased collenchyma tissue and sclereid cell frequency. Aerial petioles also had a larger cross-sectional area and were more elliptical. Thus, subtle changes in the distribution of materials, rather than differences in their makeup, differentiate petiole forms. We suggest that the growth of aerial petioles may be an adaptive response to shading, allowing aerial leaves to rise above a crowded water surface.

Domain morphology, boundaries, and topological defects in biophotonic gyroid nanostructures of butterfly wing scales

PubMed Central

Singer, Andrej; Boucheron, Leandra; Dietze, Sebastian H.; Jensen, Katharine E.; Vine, David; McNulty, Ian; Dufresne, Eric R.; Prum, Richard O.; Mochrie, Simon G. J.; Shpyrko, Oleg G.

2016-01-01

Many organisms in nature have evolved sophisticated cellular mechanisms to produce photonic nanostructures and, in recent years, diverse crystalline symmetries have been identified and related to macroscopic optical properties. However, because we know little about the distributions of domain sizes, the orientations of photonic crystals, and the nature of defects in these structures, we are unable to make the connection between the nanostructure and its development and functionality. We report on nondestructive studies of the morphology of chitinous photonic crystals in butterfly wing scales. Using spatially and angularly resolved x-ray diffraction, we find that the domains are highly oriented with respect to the whole scale, indicating growth from scale boundaries. X-ray coherent diffractive imaging reveals two types of crystalline domain interfaces: abrupt changes between domains emerging from distinct nucleation sites and smooth transitions with edge dislocations presumably resulting from internal stresses during nanostructure development. Our study of the scale structure reveals new aspects of photonic crystal growth in butterfly wings and shows their similarity to block copolymer materials. It opens new avenues to exploration of fundamental processes underlying the growth of biological photonic nanostructures in a variety of species. PMID:27386575

Domain morphology, boundaries, and topological defects in biophotonic gyroid nanostructures of butterfly wing scales.

PubMed

Singer, Andrej; Boucheron, Leandra; Dietze, Sebastian H; Jensen, Katharine E; Vine, David; McNulty, Ian; Dufresne, Eric R; Prum, Richard O; Mochrie, Simon G J; Shpyrko, Oleg G

2016-06-01

Many organisms in nature have evolved sophisticated cellular mechanisms to produce photonic nanostructures and, in recent years, diverse crystalline symmetries have been identified and related to macroscopic optical properties. However, because we know little about the distributions of domain sizes, the orientations of photonic crystals, and the nature of defects in these structures, we are unable to make the connection between the nanostructure and its development and functionality. We report on nondestructive studies of the morphology of chitinous photonic crystals in butterfly wing scales. Using spatially and angularly resolved x-ray diffraction, we find that the domains are highly oriented with respect to the whole scale, indicating growth from scale boundaries. X-ray coherent diffractive imaging reveals two types of crystalline domain interfaces: abrupt changes between domains emerging from distinct nucleation sites and smooth transitions with edge dislocations presumably resulting from internal stresses during nanostructure development. Our study of the scale structure reveals new aspects of photonic crystal growth in butterfly wings and shows their similarity to block copolymer materials. It opens new avenues to exploration of fundamental processes underlying the growth of biological photonic nanostructures in a variety of species.

Giant basal spicule from the deep-sea glass sponge Monorhaphis chuni: synthesis of the largest bio-silica structure on Earth by silicatein

NASA Astrophysics Data System (ADS)

Wang, Xiao-hong; Zhang, Xue-hua; Schröder, Heinz C.; Müller, Werner E. G.

2009-09-01

Like all sponges (phylum Porifera), the glass sponges (Hexactinellida) are provided with an elaborate and distinct body plan, which relies on a filigree skeleton. It is constructed by an array of morphologically determined elements, the spicules. Schulze described the largest siliceous hexactinellid sponge on Earth, the up to 3 m high Monorhaphis chuni, collected during the German Deep Sea Expedition "Valdivia" (1898-1899). This species develops an equally large bio-silica structure, the giant basal spicule (3 m × 10 mm). Using these spicules as a model, one can obtain the basic knowledge on the morphology, formation, and development of silica skeletal elements. The silica matrix is composed of almost pure silica, endowing it with unusual optophysical properties, which are superior to those of man-made waveguides. Experiments suggest that the spicules function in vivo as a nonocular photoreception system. The spicules are also provided with exceptional mechanical properties. Like demosponges, the hexactinellids synthesize their silica enzymatically via the enzyme silicatein (27 kDa protein). This enzyme is located in/embedded in the silica layers. This knowledge will surely contribute to a further utilization and exploration of silica in biomaterial/biomedical science.

Phylogeographic and population genetic analyses reveal multiple species of Boa and independent origins of insular dwarfism.

PubMed

Card, Daren C; Schield, Drew R; Adams, Richard H; Corbin, Andrew B; Perry, Blair W; Andrew, Audra L; Pasquesi, Giulia I M; Smith, Eric N; Jezkova, Tereza; Boback, Scott M; Booth, Warren; Castoe, Todd A

2016-09-01

Boa is a Neotropical genus of snakes historically recognized as monotypic despite its expansive distribution. The distinct morphological traits and color patterns exhibited by these snakes, together with the wide diversity of ecosystems they inhabit, collectively suggest that the genus may represent multiple species. Morphological variation within Boa also includes instances of dwarfism observed in multiple offshore island populations. Despite this substantial diversity, the systematics of the genus Boa has received little attention until very recently. In this study we examined the genetic structure and phylogenetic relationships of Boa populations using mitochondrial sequences and genome-wide SNP data obtained from RADseq. We analyzed these data at multiple geographic scales using a combination of phylogenetic inference (including coalescent-based species delimitation) and population genetic analyses. We identified extensive population structure across the range of the genus Boa and multiple lines of evidence for three widely-distributed clades roughly corresponding with the three primary land masses of the Western Hemisphere. We also find both mitochondrial and nuclear support for independent origins and parallel evolution of dwarfism on offshore island clusters in Belize and Cayos Cochinos Menor, Honduras. Copyright © 2016 Elsevier Inc. All rights reserved.

Division of Giardia isolates from humans into two genetically distinct assemblages by electrophoretic analysis of enzymes encoded at 27 loci and comparison with Giardia muris.

PubMed

Mayrhofer, G; Andrews, R H; Ey, P L; Chilton, N B

1995-07-01

Giardia that infect humans are known to be heterogeneous but they are assigned currently to a single species, Giardia intestinalis (syn. G. lamblia). The genetic differences that exist within G. intestinalis have not yet been assessed quantitatively and neither have they been compared in magnitude with those that exist between G. intestinalis and species that are morphologically similar (G. duodenalis) or morphologically distinct (e.g. G. muris). In this study, 60 Australian isolates of G. intestinalis were analysed electrophoretically at 27 enzyme loci and compared with G. muris and a feline isolate of G. duodenalis. Isolates of G. intestinalis were distinct genetically from both G. muris (approximately 80% fixed allelic differences) and the feline G. duodenalis isolate (approximately 75% fixed allelic differences). The G. intestinalis isolates were extremely heterogeneous but they fell into 2 major genetic assemblages, separated by fixed allelic differences at approximately 60% of loci examined. The magnitude of the genetic differences between the G. intestinalis assemblages approached the level that distinguished the G. duodenalis isolate from the morphologically distinct G. muris. This raises important questions about the evolutionary relationships of the assemblages with Homo sapiens, the possibility of ancient or contemporary transmission from animal hosts to humans and the biogeographical origins of the two clusters.

Neuroarchitecture and neuroanatomy of the Drosophila central complex: A GAL4-based dissection of protocerebral bridge neurons and circuits.

PubMed

Wolff, Tanya; Iyer, Nirmala A; Rubin, Gerald M

2015-05-01

Insects exhibit an elaborate repertoire of behaviors in response to environmental stimuli. The central complex plays a key role in combining various modalities of sensory information with an insect's internal state and past experience to select appropriate responses. Progress has been made in understanding the broad spectrum of outputs from the central complex neuropils and circuits involved in numerous behaviors. Many resident neurons have also been identified. However, the specific roles of these intricate structures and the functional connections between them remain largely obscure. Significant gains rely on obtaining a comprehensive catalog of the neurons and associated GAL4 lines that arborize within these brain regions, and on mapping neuronal pathways connecting these structures. To this end, small populations of neurons in the Drosophila melanogaster central complex were stochastically labeled using the multicolor flip-out technique and a catalog was created of the neurons, their morphologies, trajectories, relative arrangements, and corresponding GAL4 lines. This report focuses on one structure of the central complex, the protocerebral bridge, and identifies just 17 morphologically distinct cell types that arborize in this structure. This work also provides new insights into the anatomical structure of the four components of the central complex and its accessory neuropils. Most strikingly, we found that the protocerebral bridge contains 18 glomeruli, not 16, as previously believed. Revised wiring diagrams that take into account this updated architectural design are presented. This updated map of the Drosophila central complex will facilitate a deeper behavioral and physiological dissection of this sophisticated set of structures. © 2014 Wiley Periodicals, Inc.

Phylogeny of the bee family Megachilidae (Hymenoptera: Apoidea) based on adult morphology

USDA-ARS?s Scientific Manuscript database

Megachilidae is the second largest bee family containing more than 4000 described species worldwide in two subfamilies and seven extant tribes; it also includes a few morphologically distinctive extinct lineages from the middle Eocene: one tribe (Protolithurgini) and two subtribes presently in the O...

Genetic and morphological consequences of Quaternary glaciations: A relic barbel lineage (Luciobarbus pallaryi, Cyprinidae) of Guir Basin (Algeria).

PubMed

Brahimi, Amina; Tarai, Nacer; Benhassane, Abdelkrim; Henrard, Arnaud; Libois, Roland

2016-02-01

Climatic variations during the Quaternary period had a considerable impact on landscapes and habitat fragmentation (rivers) in North Africa. These historical events can have significant consequences on the genetic structure of the populations. Indeed, geographically separated and genetically isolated populations tend to differentiate themselves through time, eventually becoming distinct lineages, allowing new species to emerge in later generations. The aim of the present study is to use genetic and morphological techniques to evaluate the major role of the Saalian glaciation (Middle Quaternary) in the establishment of the geographic space and in the evolution of the intraspecific genetic diversity, by tracing the demographic history of barbels belonging to the Luciobarbus pallaryi (Cyprinidae) species in the Guir Basin (Algeria). In this context, two populations, from two distinct and isolated sites, were studied. Analysis of the cytochrome b (cyt b) mitochondrial markers and of the "D-loop" control region has shown that the "upstream" and "downstream" Guir populations are genetically differentiated. The molecular analyses suggest that the upstream population was disconnected from this hydrographic system during the Saalian glaciation period of the Quaternary. Subsequently, it was isolated in the foggaras underground waters in the Great Western Erg, at approximately 320 000 years BP, creating, through a bottleneck effect, a new allopatric lineage referred to as "Adrar". Conversely, the high genetic diversity in the upstream Guir (Bechar) population suggests that the stock is globally in expansion. These barbels (n=52) were also examined with meristic, morphometric, osteological, and biological features. These data also reveal a complete discrimination between the two populations, with a remarkable and distinctive behavioural adaptation for the Adrar specimens: neoteny. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Issues and Perspectives in Species Delimitation using Phenotypic Data: Atlantean Evolution in Darwin's Finches.

PubMed

Cadena, Carlos Daniel; Zapata, Felipe; Jiménez, Iván

2018-03-01

Progress in the development and use of methods for species delimitation employing phenotypic data lags behind conceptual and practical advances in molecular genetic approaches. The basic evolutionary model underlying the use of phenotypic data to delimit species assumes random mating and quantitative polygenic traits, so that phenotypic distributions within a species should be approximately normal for individuals of the same sex and age. Accordingly, two or more distinct normal distributions of phenotypic traits suggest the existence of multiple species. In light of this model, we show that analytical approaches employed in taxonomic studies using phenotypic data are often compromised by three issues: 1) reliance on graphical analyses that convey little information on phenotype frequencies; 2) exclusion of characters potentially important for species delimitation following reduction of data dimensionality; and 3) use of measures of central tendency to evaluate phenotypic distinctiveness. We outline approaches to overcome these issues based on statistical developments related to normal mixture models (NMMs) and illustrate them empirically with a reanalysis of morphological data recently used to claim that there are no morphologically distinct species of Darwin's ground-finches (Geospiza). We found negligible support for this claim relative to taxonomic hypotheses recognizing multiple species. Although species limits among ground-finches merit further assessments using additional sources of information, our results bear implications for other areas of inquiry including speciation research: because ground-finches have likely speciated and are not trapped in a process of "Sisyphean" evolution as recently argued, they remain useful models to understand the evolutionary forces involved in speciation. Our work underscores the importance of statistical approaches grounded on appropriate evolutionary models for species delimitation. We discuss how NMMs offer new perspectives in the kind of inferences available to systematists, with significant repercussions on ideas about the phenotypic structure of biodiversity.

Social Communication and Vocal Recognition in Free-Ranging Rhesus Monkeys

NASA Astrophysics Data System (ADS)

Rendall, Christopher Andrew

Kinship and individual identity are key determinants of primate sociality, and the capacity for vocal recognition of individuals and kin is hypothesized to be an important adaptation facilitating intra-group social communication. Research was conducted on adult female rhesus monkeys on Cayo Santiago, Puerto Rico to test this hypothesis for three acoustically distinct calls characterized by varying selective pressures on communicating identity: coos (contact calls), grunts (close range social calls), and noisy screams (agonistic recruitment calls). Vocalization playback experiments confirmed a capacity for both individual and kin recognition of coos, but not screams (grunts were not tested). Acoustic analyses, using traditional spectrographic methods as well as linear predictive coding techniques, indicated that coos (but not grunts or screams) were highly distinctive, and that the effects of vocal tract filtering--formants --contributed more to statistical discriminations of both individuals and kin groups than did temporal or laryngeal source features. Formants were identified from very short (23 ms.) segments of coos and were stable within calls, indicating that formant cues to individual and kin identity were available throughout a call. This aspect of formant cues is predicted to be an especially important design feature for signaling identity efficiently in complex acoustic environments. Results of playback experiments involving manipulated coo stimuli provided preliminary perceptual support for the statistical inference that formant cues take precedence in facilitating vocal recognition. The similarity of formants among female kin suggested a mechanism for the development of matrilineal vocal signatures from the genetic and environmental determinants of vocal tract morphology shared among relatives. The fact that screams --calls strongly expected to communicate identity--were not individually distinctive nor recognized suggested the possibility that their acoustic structure and role in signaling identity might be constrained by functional or morphological design requirements associated with their role in signaling submission.

Do genes lie? Mitochondrial capture masks the Red Sea collector urchin's true identity (Echinodermata: Echinoidea: Tripneustes).

PubMed

Bronstein, Omri; Kroh, Andreas; Haring, Elisabeth

2016-11-01

Novel COI and bindin sequences of the Red Sea collector echinoid Tripneustes gratilla elatensis are used to show that (1) discordance between mitochondrial and nuclear loci exists in this echinoid genus, (2) Tripneustes gratilla as currently defined possibly comprises a complex of cryptic species, and (3) Red Sea Tripneustes form a genetically distinct clade in the bindin tree, which diverged from other Tripneustes clades at least 2-4million years ago. Morphological reassessment of T. gratilla elatensis shows perfect congruence between identification based on skeletal features and genetic data based on a nuclear marker sequence. Hence the Red Sea Tripneustes subspecies established by Dafni in 1983 is a distinct biological unit. All T. g. elatensis samples analyzed are highly similar to or share mtDNA haplotypes with Philippine T. g. gratilla, as do representatives from other edge-of-range occurrences. This lack of genetic structure in Indo-Pacific Tripneustes is interpreted as a result of wide-spread mitochondrial introgression. New fossil specimens from the Red Sea area confirm the sympatric occurrence of T. g. elatensis and T. g. gratilla in the northern Red Sea during Late Pleistocene, identifying a possible timing for the introgression. In addition, present-day distribution shows a contact zone in the Southern Red Sea (in the Dahlak Archipelago). T. g. elatensis, is yet another example of a Red Sea taxon historically identified as conspecific with its Indo-Pacific relatives, but which turned out to be a morphologically and genetically distinct endemic taxon, suggesting that the level of endemism in the Red Sea may still be underestimated. Copyright © 2016 Elsevier Inc. All rights reserved.

From Allergens to Battery Anodes: Nature-Inspired, Pollen Derived Carbon Architectures for Room- and Elevated- Temperature Li-ion Storage

PubMed Central

Tang, Jialiang; Pol, Vilas G.

2016-01-01

The conversion of allergic pollen grains into carbon microstructures was carried out through a facile, one-step, solid-state pyrolysis process in an inert atmosphere. The as-prepared carbonaceous particles were further air activated at 300 °C and then evaluated as lithium ion battery anodes at room (25 °C) and elevated (50 °C) temperatures. The distinct morphologies of bee pollens and cattail pollens are resembled on the final architecture of produced carbons. Scanning Electron Microscopy images shows that activated bee pollen carbon (ABP) is comprised of spiky, brain-like, and tiny spheres; while activated cattail pollen carbon (ACP) resembles deflated spheres. Structural analysis through X-ray diffraction and Raman spectroscopy confirmed their amorphous nature. X-ray photoelectron spectroscopy analysis of ABP and ACP confirmed that both samples contain high levels of oxygen and small amount of nitrogen contents. At C/10 rate, ACP electrode delivered high specific lithium storage reversible capacities (590 mAh/g at 50 °C and 382 mAh/g at 25 °C) and also exhibited excellent high rate capabilities. Through electrochemical impedance spectroscopy studies, improved performance of ACP is attributed to its lower charge transfer resistance than ABP. Current studies demonstrate that morphologically distinct renewable pollens could produce carbon architectures for anode applications in energy storage devices. PMID:26846311

Molecular control of normal and acrocona mutant seed cone development in Norway spruce (Picea abies) and the evolution of conifer ovule-bearing organs.

PubMed

Carlsbecker, Annelie; Sundström, Jens F; Englund, Marie; Uddenberg, Daniel; Izquierdo, Liz; Kvarnheden, Anders; Vergara-Silva, Francisco; Engström, Peter

2013-10-01

Reproductive organs in seed plants are morphologically divergent and their evolutionary history is often unclear. The mechanisms controlling their development have been extensively studied in angiosperms but are poorly understood in conifers and other gymnosperms. Here, we address the molecular control of seed cone development in Norway spruce, Picea abies. We present expression analyses of five novel MADS-box genes in comparison with previously identified MADS and LEAFY genes at distinct developmental stages. In addition, we have characterized the homeotic transformation from vegetative shoot to female cone and associated changes in regulatory gene expression patterns occurring in the acrocona mutant. The analyses identified genes active at the onset of ovuliferous and ovule development and identified expression patterns marking distinct domains of the ovuliferous scale. The reproductive transformation in acrocona involves the activation of all tested genes normally active in early cone development, except for an AGAMOUS-LIKE6/SEPALLATA (AGL6/SEP) homologue. This absence may be functionally associated with the nondeterminate development of the acrocona ovule-bearing scales. Our morphological and gene expression analyses give support to the hypothesis that the modern cone is a complex structure, and the ovuliferous scale the result of reductions and compactions of an ovule-bearing axillary short shoot in cones of Paleozoic conifers. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

From Allergens to Battery Anodes: Nature-Inspired, Pollen Derived Carbon Architectures for Room- and Elevated- Temperature Li-ion Storage

NASA Astrophysics Data System (ADS)

Tang, Jialiang; Pol, Vilas G.

2016-02-01

The conversion of allergic pollen grains into carbon microstructures was carried out through a facile, one-step, solid-state pyrolysis process in an inert atmosphere. The as-prepared carbonaceous particles were further air activated at 300 °C and then evaluated as lithium ion battery anodes at room (25 °C) and elevated (50 °C) temperatures. The distinct morphologies of bee pollens and cattail pollens are resembled on the final architecture of produced carbons. Scanning Electron Microscopy images shows that activated bee pollen carbon (ABP) is comprised of spiky, brain-like, and tiny spheres; while activated cattail pollen carbon (ACP) resembles deflated spheres. Structural analysis through X-ray diffraction and Raman spectroscopy confirmed their amorphous nature. X-ray photoelectron spectroscopy analysis of ABP and ACP confirmed that both samples contain high levels of oxygen and small amount of nitrogen contents. At C/10 rate, ACP electrode delivered high specific lithium storage reversible capacities (590 mAh/g at 50 °C and 382 mAh/g at 25 °C) and also exhibited excellent high rate capabilities. Through electrochemical impedance spectroscopy studies, improved performance of ACP is attributed to its lower charge transfer resistance than ABP. Current studies demonstrate that morphologically distinct renewable pollens could produce carbon architectures for anode applications in energy storage devices.

From Allergens to Battery Anodes: Nature-Inspired, Pollen Derived Carbon Architectures for Room- and Elevated-Temperature Li-ion Storage.

PubMed

Tang, Jialiang; Etacheri, Vinodkumar; Pol, Vilas G

2016-02-05

The conversion of allergic pollen grains into carbon microstructures was carried out through a facile, one-step, solid-state pyrolysis process in an inert atmosphere. The as-prepared carbonaceous particles were further air activated at 300 °C and then evaluated as lithium ion battery anodes at room (25 °C) and elevated (50 °C) temperatures. The distinct morphologies of bee pollens and cattail pollens are resembled on the final architecture of produced carbons. Scanning Electron Microscopy images shows that activated bee pollen carbon (ABP) is comprised of spiky, brain-like, and tiny spheres; while activated cattail pollen carbon (ACP) resembles deflated spheres. Structural analysis through X-ray diffraction and Raman spectroscopy confirmed their amorphous nature. X-ray photoelectron spectroscopy analysis of ABP and ACP confirmed that both samples contain high levels of oxygen and small amount of nitrogen contents. At C/10 rate, ACP electrode delivered high specific lithium storage reversible capacities (590 mAh/g at 50 °C and 382 mAh/g at 25 °C) and also exhibited excellent high rate capabilities. Through electrochemical impedance spectroscopy studies, improved performance of ACP is attributed to its lower charge transfer resistance than ABP. Current studies demonstrate that morphologically distinct renewable pollens could produce carbon architectures for anode applications in energy storage devices.

Nuclear microsatellite variation in Malagasy baobabs (Adansonia, Bombacoideae, Malvaceae) reveals past hybridization and introgression.

PubMed

Leong Pock Tsy, Jean-Michel; Lumaret, Roselyne; Flaven-Noguier, Elodie; Sauve, Mathieu; Dubois, Marie-Pierre; Danthu, Pascal

2013-12-01

Adansonia comprises nine species, six of which are endemic to Madagascar. Genetic relationships between the Malagasy species remain unresolved due to conflicting results between nuclear and plastid DNA variation. Morphologically intermediate individuals between distinct species have been identified, indicative of interspecific hybridization. In this paper, microsatellite data are used to identify potential cases of hybridization and to provide insights into the evolutionary history of the genus on Madagascar. Eleven microsatellites amplified with new primers developed for Adansonia rubrostipa were used to analyse 672 individuals collected at 27 sites for the six Malagasy species and morphologically intermediate individuals. Rates of individual admixture were examined using three Bayesian clustering programs, STRUCTURE, BAPS and NewHybrids, with no a priori species assignment. Population differentiation was coherent, with recognized species boundaries. In the four Malagasy species of section Longitubae, 8·0, 9·0 and 9·5 % of individuals with mixed genotypes were identified by BAPS, NewHybrids and STRUCTURE, respectively. At sites with sympatric populations of A. rubrostipa and A. za, NewHybrids indicated these individuals to be F2 and, predominantly, backcrosses with both parental species. In northern Madagascar, two populations of trees combining A. za and A. perrieri morphology and microsatellite alleles were identified in the current absence of the parental species. The clear genetic differentiation observed between the six species may reflect their adaptation to different assortments of climate regimes and habitats during the colonization of the island. Microsatellite variation reveals that hybridization probably occurred in secondary contact between species of section Longitubae. This type of hybridization may also have been involved in the differentiation of a local new stabilized entity showing specific microsatellite alleles and morphological characters, suggesting a potential role of hybridization in the recent history of diversification on Madagascar.

Transcriptional dynamics of a conserved gene expression network associated with craniofacial divergence in Arctic charr.

PubMed

Ahi, Ehsan Pashay; Kapralova, Kalina Hristova; Pálsson, Arnar; Maier, Valerie Helene; Gudbrandsson, Jóhannes; Snorrason, Sigurdur S; Jónsson, Zophonías O; Franzdóttir, Sigrídur Rut

2014-01-01

Understanding the molecular basis of craniofacial variation can provide insights into key developmental mechanisms of adaptive changes and their role in trophic divergence and speciation. Arctic charr (Salvelinus alpinus) is a polymorphic fish species, and, in Lake Thingvallavatn in Iceland, four sympatric morphs have evolved distinct craniofacial structures. We conducted a gene expression study on candidates from a conserved gene coexpression network, focusing on the development of craniofacial elements in embryos of two contrasting Arctic charr morphotypes (benthic and limnetic). Four Arctic charr morphs were studied: one limnetic and two benthic morphs from Lake Thingvallavatn and a limnetic reference aquaculture morph. The presence of morphological differences at developmental stages before the onset of feeding was verified by morphometric analysis. Following up on our previous findings that Mmp2 and Sparc were differentially expressed between morphotypes, we identified a network of genes with conserved coexpression across diverse vertebrate species. A comparative expression study of candidates from this network in developing heads of the four Arctic charr morphs verified the coexpression relationship of these genes and revealed distinct transcriptional dynamics strongly correlated with contrasting craniofacial morphologies (benthic versus limnetic). A literature review and Gene Ontology analysis indicated that a significant proportion of the network genes play a role in extracellular matrix organization and skeletogenesis, and motif enrichment analysis of conserved noncoding regions of network candidates predicted a handful of transcription factors, including Ap1 and Ets2, as potential regulators of the gene network. The expression of Ets2 itself was also found to associate with network gene expression. Genes linked to glucocorticoid signalling were also studied, as both Mmp2 and Sparc are responsive to this pathway. Among those, several transcriptional targets and upstream regulators showed differential expression between the contrasting morphotypes. Interestingly, although selected network genes showed overlapping expression patterns in situ and no morph differences, Timp2 expression patterns differed between morphs. Our comparative study of transcriptional dynamics in divergent craniofacial morphologies of Arctic charr revealed a conserved network of coexpressed genes sharing functional roles in structural morphogenesis. We also implicate transcriptional regulators of the network as targets for future functional studies.

Taxonomic status of Pseudopaludicola riopiedadensis Mercadal de Barrio and Barrio, 1994 (Anura, Leptodactylidae, Leiuperinae).

PubMed

Cardozo, Darío; Toledo, Luís Felipe

2013-11-08

Pseudopaludicola riopiedadensis was described by Mercadal de Barrio and Barrio (1994) based on two adult females collected by Luiz Dino Vizotto in 1963 from Rio Piedade, São José do Rio Preto, São Paulo, Brazil. This taxon was differentiated from P. ternetzi based on a series of qualitative and morphometric characters. Nevertheless, the original description and the type material of P. ternetzi were not considered by Mercadal de Barrio and Barrio, and the morphological variation of P. ternetzi was not documented. This work reviews the sample collected by Vizotto in P. riopiedadensis type locality, evaluates the advertisement calls obtained from such population, the two vouchers assigned to P. riopiedadensis, and a large data set, including type specimens of P. ternetzi to document the morphological variation along its known distribution. Results indicate that P. riopiedadensis was described on the basis of highly variable characters applied to a small sample and share the unique P. ternetzi autapomorphy, a robust body structure with immaculate belly. The lack of differentiation in both advertisement call and morphology rejects the status of P. riopiedadensis as distinct species, and we therefore suggest to formally consider P. riopiedadensis as junior synonym of P. ternetzi.

Cell death monitoring using quantitative optical coherence tomography methods

NASA Astrophysics Data System (ADS)

Farhat, Golnaz; Yang, Victor X. D.; Kolios, Michael C.; Czarnota, Gregory J.

2011-03-01

Cell death is characterized by a series of predictable morphological changes, which modify the light scattering properties of cells. We present a multi-parametric approach to detecting changes in subcellular morphology related to cell death using optical coherence tomography (OCT). Optical coherence tomography data were acquired from acute myeloid leukemia (AML) cells undergoing apoptosis over a period of 48 hours. Integrated backscatter (IB) and spectral slope (SS) were computed from OCT backscatter spectra and statistical parameters were extracted from a generalized gamma (GG) distribution fit to OCT signal intensity histograms. The IB increased by 2-fold over 48 hours with significant increases observed as early as 4 hours. The SS increased in steepness by 2.5-fold with significant changes at 12 hours, while the GG parameters were sensitive to apoptotic changes at 24 to 48 hours. Histology slides indicated nuclear condensation and fragmentation at 24 hours, suggesting the late scattering changes could be related to nuclear structure. A second series of measurements from AML cells treated with cisplatin, colchicine or ionizing radiation suggested that the GG parameters could potentially differentiate between modes of cell death. Distinct cellular morphology was observed in histology slides obtained from cells treated under each condition.

Nanoparticle titanium dioxide aqueous interfacial energy can be modified to control phase stability, coarsening, and morphology

NASA Astrophysics Data System (ADS)

Finnegan, Michael Patrick

The effect of solution chemistry on the phase stability, coarsening kinetics and morphology of titanium dioxide (TiO2) nanoparticles is investigated in order to attain efficient production pathways to desired nano-structures with optimal properties. To obtain sample, TiO2 was synthesized via hydrolysis of titanium isopropoxide producing an 85% anatase/15% brookite mixture. The titania was hydrothermally heated in an array of temperatures and pH values for various times. There are distinct phase stability fields for nanoscale titania based on pH alone due to slight interface charging behavior differences among the polymorphs. The mixture transforms to rutile below the pH of zero point of charge (ZPC) and remains anatase above the ZPC. This phenomenon is partially reversible. The solution chemistry also dictates the hydrothermal coarsening mechanism of the anatase polymorph. Ostwald ripening (OR) takes place in basic pH where titania solubility is elevated relative to neutral pH where lower solubility prevents rapid OR but allows for coarsening via oriented attachment (OA) of nanoparticles. This OA event can alter the symmetry of anatase causing unexpected and perhaps technically useful morphologies such as straight and curved nanorods during coarsening.

Raman-atomic force microscopy of the ommatidial surfaces of Dipteran compound eyes.

PubMed

Anderson, Mark S; Gaimari, Stephen D

2003-06-01

The ommatidial lens surfaces of the compound eyes in several species of files (Insecta: Diptera) and a related order (Mecoptera) were analyzed using a recently developed Raman-atomic force microscope. We demonstrate in this work that the atomic force microscope (AFM) is a potentially useful instrument for gathering phylogenetic data and that the newly developed Raman-AFM may extend this application by revealing nanometer-scale surface chemistry. This is the first demonstration of apertureless near-field Raman spectroscopy on an intact biological surface. For Chrysopilus testaceipes Bigot (Rhagionidae), this reveals unique cerebral cortex-like surface ridges with periodic variation in height and surface chemistry. Most other Brachyceran flies, and the "Nematoceran" Sylvicola fenestralis (Scopoli) (Anisopodidae), displayed the same morphology, while other taxa displayed various other characteristics, such as a nodule-like (Tipula (Triplicitipula) sp. (Tipulidae)) or coalescing nodule-like (Tabanus punctifer Osten Sacken (Tabanidae)) morphology, a smooth morphology with distinct pits and grooves (Dilophus orbatus (Say) (Bibionidae)), or an entirely smooth surface (Bittacus chlorostigma MacLachlan (Mecoptera: Bittacidae)). The variation in submicrometer structure and surface chemistry provides a new information source of potential phylogenetic importance, suggesting the Raman-atomic force microscope could provide a new tool useful to systematic and evolutionary inquiry.

Reciprocal Symbiont Sharing in the Lodging Mutualism between Walking Corals and Sipunculans.

PubMed

Igawa, Momoko; Hata, Hiroki; Kato, Makoto

2017-01-01

Solitary scleractinian corals of the genera Heterocyathus and Heteropsammia inhabit soft marine bottoms without attaching to hard substrata. The corallums of these genera contain a coiled cavity inhabited by a sipunculan that roams the seafloor, carrying the host coral with it. The coral serves as a sturdy shelter that protects the sipunculan from possible predators. At the same time, the sipunculan maintains the coral in an upright position on the soft bottom. This coral-sipunculan association is unique because two phylogenetically distant coral genera have developed convergent associations with sipunculans. We investigate the process of convergent evolution of two coral species, Hc. aequicostatus and Hp. cochlea, in Okinawa, Japan, with their symbiotic sipunculans, using phylogenetic and morphological analyses. Phylogenetic analyses clarified that the symbiotic sipunculans comprise two distinct clades, surprisingly both of which are associated with both coral species. The bodily habitus of the sipunculan differed between coral species and fit the morphologies of the coiled cavities of their respective host corals. Our results suggest that the two coral species share two sipunculan clades and that sipunculan morphology is plastic and determined by the internal structure of their host corals.

Raman-atomic force microscopy of the ommatidial surfaces of Dipteran compound eyes

NASA Technical Reports Server (NTRS)

Anderson, Mark S.; Gaimari, Stephen D.

2003-01-01

The ommatidial lens surfaces of the compound eyes in several species of files (Insecta: Diptera) and a related order (Mecoptera) were analyzed using a recently developed Raman-atomic force microscope. We demonstrate in this work that the atomic force microscope (AFM) is a potentially useful instrument for gathering phylogenetic data and that the newly developed Raman-AFM may extend this application by revealing nanometer-scale surface chemistry. This is the first demonstration of apertureless near-field Raman spectroscopy on an intact biological surface. For Chrysopilus testaceipes Bigot (Rhagionidae), this reveals unique cerebral cortex-like surface ridges with periodic variation in height and surface chemistry. Most other Brachyceran flies, and the "Nematoceran" Sylvicola fenestralis (Scopoli) (Anisopodidae), displayed the same morphology, while other taxa displayed various other characteristics, such as a nodule-like (Tipula (Triplicitipula) sp. (Tipulidae)) or coalescing nodule-like (Tabanus punctifer Osten Sacken (Tabanidae)) morphology, a smooth morphology with distinct pits and grooves (Dilophus orbatus (Say) (Bibionidae)), or an entirely smooth surface (Bittacus chlorostigma MacLachlan (Mecoptera: Bittacidae)). The variation in submicrometer structure and surface chemistry provides a new information source of potential phylogenetic importance, suggesting the Raman-atomic force microscope could provide a new tool useful to systematic and evolutionary inquiry.

Tracing ancient evolutionary divergence in parasites.

PubMed

Tinsley, Richard C; Tinsley, Matthew C

2016-12-01

For parasitic platyhelminths that generally lack a fossil record, there is little information on the pathways of morphological change during evolution. Polystomatid monogeneans are notable for their evolutionary diversification, having originated from ancestors on fish and radiated in parallel with tetrapod vertebrates over more than 425 million years (My). This study focuses on the genus Polystomoides that occurs almost worldwide on freshwater chelonian reptiles. Morphometric data show a major divergence in structural adaptations for attachment; this correlates with a dichotomy in micro-environmental conditions in habitats within the hosts. Species infecting the urinary tract have attachment organs with large hamuli and small suckers; species in the oro-nasal tract differ fundamentally, having small hamuli and large suckers. Zoogeographical and molecular evidence supports ancient separation of these site-specific clades: a new genus is proposed - Uropolystomoides - containing urinary tract species distinct from Polystomoides sensu stricto in oro-nasal sites. Aside from differences in attachment adaptations, body plans have probably changed little over perhaps 150 My. This case contrasts markedly with polystomatids in other vertebrate groups where major morphological changes have evolved over much shorter timescales; the chelonian parasites show highly stable morphology across their global distribution over a long period of evolution, exemplifying 'living fossils'.

Extrinsic curvature, geometric optics, and lamellar order on curved substrates

NASA Astrophysics Data System (ADS)

Kamien, Randall D.; Nelson, David R.; Santangelo, Christian D.; Vitelli, Vincenzo

2009-11-01

When thermal energies are weak, two-dimensional lamellar structures confined on a curved substrate display complex patterns arising from the competition between layer bending and compression in the presence of geometric constraints. We present broad design principles to engineer the geometry of the underlying substrate so that a desired lamellar pattern can be obtained by self-assembly. Two distinct physical effects are identified as key factors that contribute to the interaction between the shape of the underlying surface and the resulting lamellar morphology. The first is a local ordering field for the direction of each individual layer, which tends to minimize its curvature with respect to the three-dimensional embedding. The second is a nonlocal effect controlled by the intrinsic geometry of the surface that forces the normals to the (nearly incompressible) layers to lie on geodesics, leading to caustic formation as in optics. As a result, different surface morphologies with predominantly positive or negative Gaussian curvature can act as converging or diverging lenses, respectively. By combining these ingredients, as one would with different optical elements, complex lamellar morphologies can be obtained. This smectic optometry enables the manipulation of lamellar configurations for the design of materials.

The H I chronicles of little things BCDs II: The origin of IC 10's H I structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashley, Trisha; Simpson, Caroline E.; Pokhrel, Nau Raj

In this paper we analyze Very Large Array (VLA) telescope and Green Bank Telescope (GBT) atomic hydrogen (H I) data for the LITTLE THINGS (Local Irregulars That Trace Luminosity Extremes, The H I Nearby Galaxy Survey; https://science.nrao.edu/science/surveys/littlethings) blue compact dwarf galaxy IC 10. The VLA data allow us to study the detailed H I kinematics and morphology of IC 10 at high resolution while the GBT data allow us to search the surrounding area at high sensitivity for tenuous H I. IC 10's H I appears highly disturbed in both the VLA and GBT H I maps with a kinematicallymore » distinct northern H I extension, a kinematically distinct southern plume, and several spurs in the VLA data that do not follow the general kinematics of the main disk. We discuss three possible origins of its H I structure and kinematics in detail: a current interaction with a nearby companion, an advanced merger, and accretion of intergalactic medium. We find that IC 10 is most likely an advanced merger or a galaxy undergoing accretion.« less

Comparison of ultrastructural and nanomechanical signature of platelets from acute myocardial infarction and platelet activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Aiqun; Chen, Jianwei; Liang, Zhi-Hong

Acute myocardial infarction (AMI) initiation and progression follow complex molecular and structural changes in the nanoarchitecture of platelets. However, it remains poorly understood how the transformation from health to AMI alters the ultrastructural and biomechanical properties of platelets within the platelet activation microenvironment. Here, we show using an atomic force microscope (AFM) that platelet samples, including living human platelets from the healthy and AMI patient, activated platelets from collagen-stimulated model, show distinct ultrastructural imaging and stiffness profiles. Correlative morphology obtained on AMI platelets and collagen-activated platelets display distinct pseudopodia structure and nanoclusters on membrane. In contrast to normal platelets, AMImore » platelets have a stiffer distribution resulting from complicated pathogenesis, with a prominent high-stiffness peak representative of platelet activation using AFM-based force spectroscopy. Similar findings are seen in specific stages of platelet activation in collagen-stimulated model. Further evidence obtained from different force measurement region with activated platelets shows that platelet migration is correlated to the more elasticity of pseudopodia while high stiffness at the center region. Overall, ultrastructural and nanomechanical profiling by AFM provides quantitative indicators in the clinical diagnostics of AMI with mechanobiological significance.« less

Liquidambar maomingensis sp. nov. (Altingiaceae) from the late Eocene of South China.

PubMed

Maslova, Natalia P; Kodrul, Tatiana M; Song, Yunsheng; Volkova, Lyudmila D; Jin, Jianhua

2015-08-01

• Phylogenetic analysis of DNA sequence data has changed our view on the evolution and systematics of plant taxa. Based on the phylogenetic analysis of several molecular markers, fruit anatomy, and pollen morphology, the genera Altingia and Semiliquidambar were formally transferred to the genus Liquidambar. The new species of Liquidambar from the Eocene of South China significantly extends our knowledge of the variability of the morphological characters of this genus in the geological past. Fossil leaves in conjunction with data on the associated reproductive structures allow us to make inferences about patterns in the evolutionary history of Liquidambar.• Fossil leaves and associated reproductive structures preserved as impressions were described and compared with the corresponding organs of extant and fossil relatives. The morphological variation of numerous leaves was examined by stereomicroscopy.• Liquidambar maomingensis sp. nov. is characterized by polymorphic leaves including both palmately lobed and unlobed leaves. This study presents the first observations of such dimorphism in the fossil record of Liquidambar leaves. Two distinct leaf groups are interpreted as sun and shade leaves.• The fossil leaves and associated infructescences from Maoming probably belong to the same plant. The occurrence of fossil leaves similar to those of extant species previously considered within Semiliquidambar and Liquidambar with the associated infructescences close to those of Altingia provide paleobotanical evidence that justifies combining the genera Liquidambar, Altingia, and Semiliquidambar into the single genus Liquidambar as recently proposed based on molecular markers. © 2015 Botanical Society of America, Inc.

Normal variation in fronto-occipital circuitry and cerebellar structure with an autism-associated polymorphism of CNTNAP2

PubMed Central

Tan, Geoffrey C.Y.; Doke, Thomas F.; Ashburner, John; Wood, Nicholas W.; Frackowiak, Richard S.J.

2010-01-01

Recent genetic studies have implicated a number of candidate genes in the pathogenesis of Autism Spectrum Disorder (ASD). Polymorphisms of CNTNAP2 (contactin-associated like protein-2), a member of the neurexin family, have already been implicated as a susceptibility gene for autism by at least 3 separate studies. We investigated variation in white and grey matter morphology using structural MRI and diffusion tensor imaging. We compared volumetric differences in white and grey matter and fractional anisotropy values in control subjects characterised by genotype at rs7794745, a single nucleotide polymorphism in CNTNAP2. Homozygotes for the risk allele showed significant reductions in grey and white matter volume and fractional anisotropy in several regions that have already been implicated in ASD, including the cerebellum, fusiform gyrus, occipital and frontal cortices. Male homozygotes for the risk alleles showed greater reductions in grey matter in the right frontal pole and in FA in the right rostral fronto-occipital fasciculus compared to their female counterparts who showed greater reductions in FA of the anterior thalamic radiation. Thus a risk allele for autism results in significant cerebral morphological variation, despite the absence of overt symptoms or behavioural abnormalities. The results are consistent with accumulating evidence of CNTNAP2's function in neuronal development. The finding suggests the possibility that the heterogeneous manifestations of ASD can be aetiologically characterised into distinct subtypes through genetic-morphological analysis. PMID:20176116

Geological History of the Tyre Region of Europa: A Regional Perspective on Europan Surface Features and Ice Thickness

NASA Technical Reports Server (NTRS)

Kadel, Steven D.; Chuang, Frank C.; Greeley, Ronald; Moore, Jeffrey M.

2000-01-01

Galileo images of the Tyre Macula region of Europa at regional (170 m/pixel) and local (approx. 40 m/pixel) scales allow mapping and understanding of surface processes and landforms. Ridged plains, doublet and complex ridges, shallow pits, domes, "chaos" areas. impact structures, tilted blocks and massifs, and young fracture systems indicate a complex history of surface deformation on Europa. Regional and local morphologies of the Tyre region of Europa suggest that an impactor penetrated through several kilometers of water ice tc a mobile layer below. The surface morphology was initially dominated by formation of ridged plains, followed by development of ridge bands and doublet ridges, with chaos and fracture formation dominating the latter part of the geologic history of the Tyre region. Two distinct types of chaos have been identified which, along with upwarped dome materials, appear to represent a continuum of features (domes-play chaos-knobby chaos) resulting from increasing degree of surface disruption associated with local lithospheric heating and thinning. Local and regional stratigraphic relationships, block heights, and the morphology of the Tyre impact structure suggest the presence of low-viscosity ice or liquid water beneath a thin (severa1 kilometers) surface ice shell at the time of the impact. The very low impact crater density on the surface of Europa suggests that this thin shell has either formed or been thoroughly resurfaced in the very recent past.

Paleobiology of distinctive benthic microfossils from the upper Proterozoic Limestone-Dolomite "Series," central East Greenland

NASA Technical Reports Server (NTRS)

Green, J. W.; Knoll, A. H.; Golubic, S.; Swett, K.

1987-01-01

Populations of Polybessurus bipartitus Fairchild ex Green et al., a large morphologically distinctive microfossil, occur in silicified carbonates of the Upper Proterozoic (700-800 Ma) Limestone-Dolomite "Series," central East Greenland. Large populations of well-preserved individuals permit reconstruction of P. bipartitus as a coccoidal unicell that "jetted" upward from the sediment by the highly unidirectional secretion of extracellular mucopolysaccharide envelopes. Reproduction by baeocyte formation is inferred on the basis of clustered envelope stalks produced by small cells. Sedimentological evidence indicates that P. bipartitus formed surficial crusts locally within a shallow peritidal carbonate platform. Among living microorganisms a close morphological, reproductive, and behavioral counterpart to Polybessurus is provided by populations of an as yet underscribed cyanobacterium found in coastal Bahamian environments similar to those in which the Proterozoic fossils occur. In general morphology and "jetting" behavior, this population resembles species of the genus Cyanostylon, Geitler (1925), but reproduces via baeocyte formation. Polybessurus is but one of the more than two dozen taxa in the richly fossiliferous biota of the Limestone-Dolomite "Series." This distinctive population, along with co-occurring filamentous cyanobacteria and other microfossils, contributes to an increasingly refined picture of ecological heterogeneity in late Proterozoic oceans.

Paleobiology of distinctive benthic microfossils from the upper Proterozoic Limestone-Dolomite "Series," central East Greenland.

PubMed

Green, J W; Knoll, A H; Golubic, S; Swett, K

1987-01-01

Populations of Polybessurus bipartitus Fairchild ex Green et al., a large morphologically distinctive microfossil, occur in silicified carbonates of the Upper Proterozoic (700-800 Ma) Limestone-Dolomite "Series," central East Greenland. Large populations of well-preserved individuals permit reconstruction of P. bipartitus as a coccoidal unicell that "jetted" upward from the sediment by the highly unidirectional secretion of extracellular mucopolysaccharide envelopes. Reproduction by baeocyte formation is inferred on the basis of clustered envelope stalks produced by small cells. Sedimentological evidence indicates that P. bipartitus formed surficial crusts locally within a shallow peritidal carbonate platform. Among living microorganisms a close morphological, reproductive, and behavioral counterpart to Polybessurus is provided by populations of an as yet underscribed cyanobacterium found in coastal Bahamian environments similar to those in which the Proterozoic fossils occur. In general morphology and "jetting" behavior, this population resembles species of the genus Cyanostylon, Geitler (1925), but reproduces via baeocyte formation. Polybessurus is but one of the more than two dozen taxa in the richly fossiliferous biota of the Limestone-Dolomite "Series." This distinctive population, along with co-occurring filamentous cyanobacteria and other microfossils, contributes to an increasingly refined picture of ecological heterogeneity in late Proterozoic oceans.

Competing pathways determine fibril morphology in the self-assembly of beta2-microglobulin into amyloid.

PubMed

Gosal, Walraj S; Morten, Isobel J; Hewitt, Eric W; Smith, D Alastair; Thomson, Neil H; Radford, Sheena E

2005-08-26

Despite its importance in biological phenomena, a comprehensive understanding of the mechanism of amyloid formation remains elusive. Here, we use atomic force microscopy to map the formation of beta2-microglobulin amyloid fibrils with distinct morphologies and persistence lengths, when protein concentration, pH and ionic strength are varied. Using the resulting state-diagrams, we demonstrate the existence of two distinct competitive pathways of assembly, which define an energy landscape that rationalises the sensitivity of fibril morphology on the solution conditions. Importantly, we show that semi-flexible (worm-like) fibrils, which form rapidly during assembly, are kinetically trapped species, formed via a non-nucleated pathway that is explicitly distinct from that leading to the formation of the relatively rigid long-straight fibrils classically associated with amyloid. These semi-flexible fibrils also share an antibody epitope common to other protein oligomers that are known to be toxic species linked to human disease. The results demonstrate the heterogeneity of amyloid assembly, and have important implications for our understanding of the importance of oligomeric states in amyloid disease, the origins of prion strains, and the development of therapeutic strategies.

Integrative Taxonomy of Southeast Asian Snail-Eating Turtles (Geoemydidae: Malayemys) Reveals a New Species and Mitochondrial Introgression

PubMed Central

Ihlow, Flora; Vamberger, Melita; Flecks, Morris; Hartmann, Timo; Cota, Michael; Makchai, Sunchai; Meewattana, Pratheep; Dawson, Jeffrey E.; Kheng, Long; Rödder, Dennis; Fritz, Uwe

2016-01-01

Based on an integrative taxonomic approach, we examine the differentiation of Southeast Asian snail-eating turtles using information from 1863 bp of mitochondrial DNA, 12 microsatellite loci, morphology and a correlative species distribution model. Our analyses reveal three genetically distinct groups with limited mitochondrial introgression in one group. All three groups exhibit distinct nuclear gene pools and distinct morphology. Two of these groups correspond to the previously recognized species Malayemys macrocephala (Chao Phraya Basin) and M. subtrijuga (Lower Mekong Basin). The third and genetically most divergent group from the Khorat Basin represents a previously unrecognized species, which is described herein. Although Malayemys are extensively traded and used for religious release, only few studied turtles appear to be translocated by humans. Historic fluctuations in potential distributions were assessed using species distribution models (SDMs). The Last Glacial Maximum (LGM) projection of the predictive SDMs suggests two distinct glacial distribution ranges, implying that the divergence of M. macrocephala and M. subtrijuga occurred in allopatry and was triggered by Pleistocene climate fluctuations. Only the projection derived from the global circulation model MIROC reveals a distinct third glacial distribution range for the newly discovered Malayemys species. PMID:27050302

Evolution of the hypercarnivorous dentition in mammals (Metatheria, Eutheria) and its bearing on the development of tribosphenic molars.

PubMed

Solé, Floréal; Ladevèze, Sandrine

2017-03-01

One major innovation of mammals is the tribosphenic molar, characterized by the evolution of a neomorphic upper cusp (=protocone) and a lower basin (=talonid) that occlude and provide shearing and crushing functions. This type of molar is an evolutionarily flexible structure that enabled mammals to achieve complex dental adaptations. Among carnivorous mammals, hypercarnivory is a common trend that evolved several times among therians (marsupials, placentals, and stem relatives). Hypercarnivory involves an important simplification of the carnassial molar pattern from the ancestral tribosphenic molar pattern, with the modification of the triangular tooth crown, and the loss of several cusps and cuspids typical of the tribosphenic molar. These losses confer to the molars of the hypercarnivorous mammals a plesiomorphic/paedomorphic morphology that resembles more the earliest mammaliaforms than the earliest therians. Here, we demonstrate that the modification of the molar morphology is fully explained by a patterning cascade mode of cusp development. Contrary to what was previously proposed, our study concludes that the metaconid (mesiolingual cusp of lower molars, associated with a puncturing function) does not influence cusp development of the talonid (distal crushing heel of lower molars). Moreover, it provides a new example of how heterochronic changes were crucial to the evolution of mammal dentition. To overcome the difficulty of applying behavioral or ecological definitions of diets to fossil animals, we characterize hypercarnivorous dentitions on the basis of the molar morphology and more particularly on the loss or retention of crushing structures, each dentition resulting from adaptations to a distinct ecomorphotype. Despite repeated and convergent evolution of hypercarnivorous forms, hypercarnivory appears as a highly constrained specialization (i.e., "dead end") that is unlikely to evolve back to omnivorous dentition, especially when the crushing structures are lost. © 2017 Wiley Periodicals, Inc.

Lithography-Free Fabrication of Reconfigurable Substrate Topography For Contact Guidance

PubMed Central

Pholpabu, Pitirat; Kustra, Stephen; Wu, Haosheng; Balasubramanian, Aditya; Bettinger, Christopher J.

2014-01-01

Mammalian cells detect and respond to topographical cues presented in natural and synthetic biomaterials both in vivo and in vitro. Micro- and nano-structures influence the adhesion, morphology, proliferation, migration, and differentiation of many phenotypes. Although the mechanisms that underpin cell-topography interactions remain elusive, synthetic substrates with well-defined micro- and nano-structures are important tools to elucidate the origin of these responses. Substrates with reconfigurable topography are desirable because programmable cues can be harmonized with dynamic cellular responses. Here we present a lithography-free fabrication technique that can reversibly present topographical cues using an actuation mechanism that minimizes the confounding effects of applied stimuli. This method utilizes strain-induced buckling instabilities in bi-layer substrate materials with rigid uniform silicon oxide membranes that are thermally deposited on elastomeric substrates. The resulting surfaces are capable of reversible of substrates between three distinct states: flat substrates (A = 1.53 ± 0.55 nm, Rms = 0.317 ± 0.048 nm); parallel wavy grating arrays (A|| = 483.6 ± 7.8 nm and λ|| = 4.78 ± 0.16 μm); perpendicular wavy grating arrays (A⊥ = 429.3 ± 5.8 nm; λ⊥ = 4.95 ± 0.36 μm). The cytoskeleton dynamics of 3T3 fibroblasts in response to these surfaces was measured using optical microscopy. Fibroblasts cultured on dynamic substrates that are switched from flat to topographic features (FLAT-WAVY) exhibit a robust and rapid change in gross morphology as measured by a reduction in circularity from 0.30 ± 0.13 to 0.15 ± 0.08 after 5 min. Conversely, dynamic substrate sequences of FLAT-WAVY-FLAT do not significantly alter the gross steady-state morphology. Taken together, substrates that present topographic structures reversibly can elucidate dynamic aspects of cell-topography interactions. PMID:25468368

Albumin Evolution in Frogs: A Test of the Evolutionary Clock Hypothesis

PubMed Central

Wallace, Donald G.; Maxson, Linda R.; Wilson, Allan C.

1971-01-01

Frogs are an ancient group compared to placental mammals. Yet, although there are about as many species of frogs as there are of mammals, zoologists consider that frogs have undergone only limited morphological divergence, while placental mammals have diversified greatly in morphology and way of life. The serum albumins of numerous frog species were compared by the quantitative microcomplement fixation technique. Frogs that are morphologically similar enough to merit taxonomic distinction at only the species level often exhibit differences in the serological properties of their albumins larger than those usually seen between mammals placed in distinct families or suborders. Thus, there seems to be a contrast between albumin evolution and evolution at the organismal level. The large differences between albumins among frogs can be explained by the hypothesis that albumin evolution has proceeded at the same rate in frogs as in mammals. PMID:5002283

In-Situ Atomic Force Microscope Imaging of Calcite Etch Pit Morphology Changes in Undersaturated and 1-Hydroxyethylidene-1,1-diphosphonic Acid Poisoned Solutions

PubMed Central

Britt, David W.

2012-01-01

Morphology changes in etch pits formed on the (1014) cleavage plane of calcite were induced by varying the ratio of [Ca2+] to [CO32−] in the bulk solution as well as through the addition of the crystal poison 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP). Three distinct morphologies were noted: symmetric rhombic, asymmetric rhombic, and triangular with a rough curved hypotenuse. The latter represents a transient morphology which is only observed during the actual dissolution process, while the former morphologies persist after dissolution is halted. PMID:25125794

Global study of holistic morphological effectors in the budding yeast Saccharomyces cerevisiae.

PubMed

Suzuki, Godai; Wang, Yang; Kubo, Karen; Hirata, Eri; Ohnuki, Shinsuke; Ohya, Yoshikazu

2018-02-20

The size of the phenotypic effect of a gene has been thoroughly investigated in terms of fitness and specific morphological traits in the budding yeast Saccharomyces cerevisiae, but little is known about gross morphological abnormalities. We identified 1126 holistic morphological effectors that cause severe gross morphological abnormality when deleted, and 2241 specific morphological effectors with weak holistic effects but distinctive effects on yeast morphology. Holistic effectors fell into many gene function categories and acted as network hubs, affecting a large number of morphological traits, interacting with a large number of genes, and facilitating high protein expression. Holistic morphological abnormality was useful for estimating the importance of a gene to morphology. The contribution of gene importance to fitness and morphology could be used to efficiently classify genes into functional groups. Holistic morphological abnormality can be used as a reproducible and reliable gene feature for high-dimensional morphological phenotyping. It can be used in many functional genomic applications.

Physiology modulates social flexibility and collective behaviour in equids and other large ungulates.

PubMed

Gersick, Andrew S; Rubenstein, Daniel I

2017-08-19

Though morphologically very similar, equids across the extant species occupy ecological niches that are surprisingly non-overlapping. Occupancy of these distinct niches appears related to subtle physiological and behavioural adaptations which, in turn, correspond to significant differences in the social behaviours and emergent social systems characterizing the different species. Although instances of intraspecific behavioural variation in equids demonstrate that the same body plan can support a range of social structures, each of these morphologically similar species generally shows robust fidelity to its evolved social system. The pattern suggests a subtle relationship between physiological phenotypes and behavioural flexibility. While environmental conditions can vary widely within relatively short temporal or spatial scales, physiological changes and changes to the behaviours that regulate physiological processes, are constrained to longer cycles of adaptation. Physiology is then the limiting variable in the interaction between ecological variation and behavioural and socio-structural flexibility. Behavioural and socio-structural flexibility, in turn, will generate important feedbacks that will govern physiological function, thus creating a coupled web of interactions that can lead to changes in individual and collective behaviour. Longitudinal studies of equid and other large-bodied ungulate populations under environmental stress, such as those discussed here, may offer the best opportunities for researchers to examine, in real time, the interplay between individual behavioural plasticity, socio-structural flexibility, and the physiological and genetic changes that together produce adaptive change.This article is part of the themed issue 'Physiological determinants of social behaviour in animals'. © 2017 The Author(s).

The Formation of Chimeric Nanomorphologies, as a Reflection of Naturally Occurring Thermodynamic Processes

NASA Astrophysics Data System (ADS)

Naziris, N.; Demetzos, C.

2017-11-01

The self-assembly process of different in nature biomaterials leads to the morphogenesis of various nano-structures, where the individual molecule properties (e.g. hydrophilic-to-hydrophobic balance and elasticity), profoundly affect the intermediate surfaces’ interfacial thermodynamics. Herein, the mixing of a phospholipid and an amphiphilic block copolymer, through the thin-film hydration method, gave different morphologies, among which there were vesicles (i.e. liposomes and polymersomes), micelles and worm-like structures. The formation of such variety of structures is attributed to divergent entropic pathways, which are determined by a number of parameters, such as the lipid:polymer molar ratio and the polymer composition. The developed nanosystems are considered as chimeric/mixed, because of the two different in type biomaterials that compose them. The vesicles also exhibited membrane “irregularities”, which are connected with their biophysical behavior. Nature has “chosen” vesicular forms to be the thermodynamically stable “biological apartments”, in which life was enclosed and additionally, vesicles provided compartmentalized systems, where the intracellular environment was built. Phospholipid properties result in membranes/bilayers that harmonically assimilate other molecules, like proteins and retain their integrity and functionality, while gaining additional features. A cause that alters this relationship might induce changes in the membrane composition and morphology, with respect to lipid rafts/domains, what has been linked with the activation and development of certain human disorders/diseases. The self-assembly of two different biomaterials into various structures that present distinct membrane phenomena is believed to simulate these natural processes.

Morphology of the Epidermis of the Neotropical Catfish Pimelodella lateristriga (Lichtenstein, 1823) with Emphasis in Club Cells

PubMed Central

Damasceno, Eduardo Medeiros; Monteiro, Juliana Castro; Duboc, Luiz Fernando; Dolder, Heidi; Mancini, Karina

2012-01-01

The epidermis of Ostariophysi fish is composed of 4 main cell types: epidermal cells (or filament containing cells), mucous cells, granular cells and club cells. The morphological analysis of the epidermis of the catfish Pimelodella lateristriga revealed the presence of only two types of cells: epidermal and club cells. The latter were evident in the middle layer of the epidermis, being the largest cells within the epithelium. Few organelles were located in the perinuclear region, while the rest of the cytoplasm was filled with a non-vesicular fibrillar substance. Club cells contained two irregular nuclei with evident nucleoli and high compacted peripheral chromatin. Histochemical analysis detected prevalence of protein within the cytoplasm other than carbohydrates, which were absent. These characteristics are similar to those described to most Ostariophysi studied so far. On the other hand, the epidermal cells differ from what is found in the literature. The present study described three distinct types, as follows: superficial, abundant and dense cells. Differences among them were restricted to their cytoplasm and nucleus morphology. Mucous cells were found in all Ostariophysi studied so far, although they were absent in P. lateristriga, along with granular cells, also typical of other catfish epidermis. The preset study corroborates the observations on club cells' morphology in Siluriformes specimens, and shows important differences in epidermis composition and cell structure of P. lateristriga regarding the literature data. PMID:23226253

pH and Amphiphilic Structure Direct Supramolecular Behavior in Biofunctional Assemblies

DOE PAGES

Moyer, Tyson J.; Finbloom, Joel A.; Chen, Feng; ...

2014-10-13

Supramolecular self-assembly offers promising new ways to control nanostructure morphology and respond to external stimuli. A pH-sensitive self-assembled system was developed to both control nanostructure shape and respond to the acidic microenvironment of tumors using self-assembling peptide amphiphiles (PAs). Here, by incorporating an oligo-histidine H 6 sequence, we developed two PAs that self-assembled into distinct morphologies on the nanoscale, either as nanofibers or spherical micelles, based on the incorporation of the aliphatic tail on the N-terminus or near the C-terminus, respectively. Both cylinder and sphere-forming PAs demonstrated reversible disassembly between pH 6.0 and 6.5 upon protonation of the histidine residuesmore » in acidic solutions. These PAs were then characterized and assessed for their potential to encapsulate hydrophobic chemotherapies. The H 6-based nanofiber assemblies encapsulated camptothecin (CPT) with up to 60% efficiency, a 7-fold increase in CPT encapsulation relative to spherical micelles. Additionally, pH-sensitive nanofibers showed improved tumor accumulation over both spherical micelles and nanofibers that did not change morphologies in acidic environments. We have demonstrated that the morphological transitions upon changes in pH of supramolecular nanostructures affect drug encapsulation and tumor accumulation. Lastly, our findings also suggest that these supramolecular events can be tuned by molecular design to improve the pharmacologic properties of nanomedicines.« less

Impact of dilution on microbial community structure and functional potential: comparison of numerical simulations and batch culture experiments

NASA Technical Reports Server (NTRS)

Franklin, R. B.; Garland, J. L.; Bolster, C. H.; Mills, A. L.

2001-01-01

A series of microcosm experiments was performed using serial dilutions of a sewage microbial community to inoculate a set of batch cultures in sterile sewage. After inoculation, the dilution-defined communities were allowed to regrow for several days and a number of community attributes were measured in the regrown assemblages. Based upon a set of numerical simulations, community structure was expected to differ along the dilution gradient; the greatest differences in structure were anticipated between the undiluted-low-dilution communities and the communities regrown from the very dilute (more than 10(-4)) inocula. Furthermore, some differences were expected among the lower-dilution treatments (e.g., between undiluted and 10(-1)) depending upon the evenness of the original community. In general, each of the procedures used to examine the experimental community structures separated the communities into at least two, often three, distinct groups. The groupings were consistent with the simulated dilution of a mixture of organisms with a very uneven distribution. Significant differences in community structure were detected with genetic (amplified fragment length polymorphism and terminal restriction fragment length polymorphism), physiological (community level physiological profiling), and culture-based (colony morphology on R2A agar) measurements. Along with differences in community structure, differences in community size (acridine orange direct counting), composition (ratio of sewage medium counts to R2A counts, monitoring of each colony morphology across the treatments), and metabolic redundancy (i.e., generalist versus specialist) were also observed, suggesting that the differences in structure and diversity of communities maintained in the same environment can be manifested as differences in community organization and function.

Morphological and molecular reassessment of graptemys oculifera and Graptemys flavimaculata (Testudines: Emydidae)

USGS Publications Warehouse

Ennen, J.R.; Kreiser, B.R.; Qualls, C.P.; Lovich, J.E.

2010-01-01

The turtle genus Graptemys consists of 15 recognized taxa, distinguished largely on the basis of pigmentation pattern (i.e., soft tissue and shell), head size, and shell morphology. However, phylogenetic studies have shown limited sequence divergence within the genus and between Graptemys oculifera and Graptemys flavimaculata relative to most other members of the Emydidae. Graptemys oculifera of the Pearl River drainage and G. flavimaculata of the Pascagoula River drainage have been recognized as species since 1890 and 1954, respectively. However, the description of G. flavimaculata was based on a limited number of morphological characters. Several of these characters overlap between G. flavimaculata and G. oculifera, and no attempt was made to test for significant morphological differentiation. In this study, we reevaluated the morphological and genetic distinctiveness of G. flavimaculata and G. oculifera with (1) multivariate statistical analyses of 44 morphological characters and (2) 1,560 bp of sequence data from two mitochondrial genes (control region and ND4). The morphological and molecular analyses produced incongruent results. The principal components analysis ordinations separated the two species along a pigmentation gradient with G. flavimaculata having more yellow pigmentation than G. oculifera. Likewise, clustering analyses separated the specimens into two distinct groups with little overlap between the species. Our mitochondrial data supported previous findings of limited genetic differentiation between the two species. However, the results of our morphological analyses, in conjunction with recently published nuclear gene sequence data, support the continued recognition of the two species. Copyright 2010 Society for the Study of Amphibians and Reptiles.

Wholeness and primary and secondary food structure effects on in vitro digestion patterns determine nutritionally distinct carbohydrate fractions in cereal foods.

PubMed

Mishra, Suman; Monro, John

2012-12-01

Starchy foods of differing structure, including bakery products, breakfast cereals, pastas, and pulses were digested in vitro. Bakery products and processed breakfast cereals with little resilient structure yielded large amounts of rapidly available carbohydrate (RAC), less slowly digested starch (SDS) and little inaccessible digestible starch (IDS) (70:22:8%). Partially processed grains, such as rolled oats contained an increased proportion of SDS (55:38:7%). Pastas, being dense starch structures digested more gradually to completion by superficial erosion, yielding approximately equal proportions of RAC and SDS but little IDS (43:52:4%). Pulses, which retained their cellular morphology, digested more linearly yielding a lower proportion of RAC, a larger proportion of SDS and more IDS (9:69:22%). Preservation of native "primary" structure, and use of processing to create "secondary" structure, are both means by which wholeness, in the sense of intactness, can be used to influence carbohydrate digestion to make foods of lower glycaemic impact. Copyright © 2012 Elsevier Ltd. All rights reserved.

Molecular interactions in self-assembled nano-structures of chitosan-sodium alginate based polyelectrolyte complexes.

PubMed

Wasupalli, Geeta Kumari; Verma, Devendra

2018-03-16

We report here the self-assembled structures of polyelectrolyte complexes (PECs) of polyanionic sodium alginate with the polycationic chitosan at room temperature. The PECs prepared at different pH values exhibited two distinct morphologies. The chitosan-alginate PECs self-assembled into the fibrous structure in a low pH range of pH3 to 7. The PECs obtained at high pH series around pH8 and above resulted in the formation of colloidal nanoparticles in the range of 120±9.48nm to 46.02±16.66nm. The zeta potential measurement showed that PECs prepared at lower pH (pH<6) exhibited nearly neutral surface charge, whereas PECs prepared at higher pH than 6 exhibited highly negative surface charge. The molecular interactions in nano-colloids and fibers were evaluated using FTIR analysis. The results attest that the ionic state of the chitosan and alginate plays an important role controlling the morphologies of the PECS. The present study has identified the enormous potential of the polyelectrolytes complexes to exploit shape by the alteration of ionic strength. These findings might be useful in the development of novel biomaterial. The produced fibers and nanocolloids could be applied as a biomaterial for tissue engineering and drug delivery. Copyright © 2017. Published by Elsevier B.V.

Morphological variation of siscowet lake trout in Lake Superior

USGS Publications Warehouse

Bronte, C.R.; Moore, S.A.

2007-01-01

Historically, Lake Superior has contained many morphologically distinct forms of the lake trout Salvelinus namaycush that have occupied specific depths and locations and spawned at specific times of the year. Today, as was probably the case historically, the siscowet morphotype is the most abundant. Recent interest in harvesting siscowets to extract oil containing omega-3 fatty acids will require additional knowledge of the biology and stock structure of these lightly exploited populations. The objective of this study was to determine whether shape differences exist among siscowet populations across Lake Superior and whether these shape differences can be used to infer stock structure. Morphometric analysis (truss protocol) was used to differentiate among siscowets sampled from 23 locations in Lake Superior. We analyzed 31 distance measurements among 14 anatomical landmarks taken from digital images of fish recorded in the field. Cluster analysis of size-corrected data separated fish into three geographic groups: The Isle Royale, eastern (Michigan), and western regions (Michigan). Finer scales of stock structure were also suggested. Discriminant function analysis demonstrated that head measurements contributed to most of the observed variation. Cross-validation classification rates indicated that 67–71% of individual fish were correctly classified to their region of capture. This is the first study to present shape differences associated with location within a lake trout morphotype in Lake Superior.

Progressive chorion morphology during egg development in Samia ricini (Donovan).

PubMed

Renthlei, Collin Z; Raghuvarman, Arumugam; Kharbuli, Besterwell; Dey, Sudip

2010-03-01

The egg of Samia ricini (Donovan), is oval or laterally flattened ellipsoid, freshly laid eggs are candid white while the chorion is colorless and semi-transparent. The surface of the chorion is covered with network patterns of polygons and their shapes are common in the whole surface region. The boundaries between polygons made ridges had distinct acropyles at three-cell junctions. The numbers of aeropyles are variable according to their structures both in the lateral flat and marginal regions. During the course of egg development, no significant structural changes were observed in either the polygonal structures or the overall morphology of the egg. However, the size of the aeropyles kept on changing as the egg matures. The aeropyle increases initially upto day-9 of egg development and then decreases as it approach hatching. Lines of weaknesses were not observed at time of hatching or close to it. Hatching process of the newly emerge larvae are through gnawing. The larva eats their way out through the chorion membrane mostly from the anterior region. Egg buster or spine which aid in hatching are not present in the newly emerge larvae.This article was published online on 25 September 2009. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected 6 January 2010.

Au-C allotrope nano-composite films at extreme conditions generated by intense ultra-short laser

NASA Astrophysics Data System (ADS)

Khan, Saif A.; Saravanan, K.; Tayyab, M.; Bagchi, S.; Avasthi, D. K.

2016-07-01

Structural evolution of gold-carbon allotrope nano-composite films under relativistically intense, ultra-short laser pulse irradiation is studied in this work. Au-C nano-composite films, having 4 and 10 at.% of Au, were deposited by co-sputtering technique on silicon substrates. Au-C60 NC films with 2.5 at.% Au were deposited on 12 μm thick Al foil using co-evaporation technique. These samples were radiated with single pulse from 45 fs, 10 TW Ti:Sapphire Laser at RRCAT at an intensity of 3 × 1018 W cm-2. The morphological and compositional changes were investigated using scanning electron microscopy (SEM) and Rutherford back-scattering spectrometry (RBS) techniques. Laser pulse created three morphologically distinct zones around the point of impact on samples with silicon substrates. The gold content in 600 μm circular region around a point of impact is found to reduce by a factor of five. Annular rings of ∼70 nm in diameter were observed in case of Au-C NC film after irradiation. Laser pulse created a hole of about 400 μm in the sample with Al foil as substrate and wavy structures of 6 μm wavelength are found to be created around this hole. The study shows radial variation in nano-structure formation with varying local intensity of laser pulse.

Characteristic Morphologies of the Bicuspid Aortic Valve in Patients with Genetic Syndromes.

PubMed

Niaz, Talha; Poterucha, Joseph T; Olson, Timothy M; Johnson, Jonathan N; Craviari, Cecilia; Nienaber, Thomas; Palfreeman, Jared; Cetta, Frank; Hagler, Donald J

2018-02-01

In patients with bicuspid aortic valve (BAV), complications including progressive aortic stenosis and aortic dilatation develop over time. The morphology of cusp fusion is one of the determinants of the type and severity of these complications. We present the association of morphology of cusp fusion in BAV patients with distinctive genetic syndromes. The Mayo Clinic echocardiography database was retrospectively reviewed to identify patients (age ≤ 22 years) diagnosed with BAV from 1990 to 2016. Cusp fusion morphology was determined from the echocardiographic studies, while coexisting cardiac defects and genetic syndromes were determined from chart review. A total of 1,037 patients with BAV were identified: 550 (53%) had an isolated BAV, 299 (29%) had BAV and a coexisting congenital heart defect, and 188 (18%) had BAV and a coexisting genetic syndrome or disorder. There were no differences in distribution of morphology across the three groups. However, right-noncoronary (RN) cusp fusion was the predominant morphology associated with Down syndrome (P = .002) and right-left (RL) cusp fusion was the predominant morphology associated with Turner syndrome (P = .02), DiGeorge syndrome (P = .02), and Shone syndrome (P = .0007), when compared with valve morphology in patients with isolated BAV. Isolated BAV patients with RN cusp fusion had larger ascending aorta diameter (P = .001) and higher number of patients with ≥ moderate aortic regurgitation (P = .02), while those with RL cusp fusion had larger sinus of Valsalva diameter (P = .0006). Morphological subtypes of BAV are associated with different genetic syndromes, suggesting distinct perturbations of developmental pathways in aortic valve malformation. Copyright © 2017 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Strain-specific Fibril Propagation by an Aβ Dodecamer

NASA Astrophysics Data System (ADS)

Dean, Dexter N.; Das, Pradipta K.; Rana, Pratip; Burg, Franklin; Levites, Yona; Morgan, Sarah E.; Ghosh, Preetam; Rangachari, Vijayaraghavan

2017-01-01

Low molecular weight oligomers of amyloid-β (Aβ) have emerged as the primary toxic agents in the etiology of Alzheimer disease (AD). Polymorphism observed within the aggregation end products of fibrils are known to arise due to microstructural differences among the oligomers. Diversity in aggregate morphology correlates with the differences in AD, cementing the idea that conformational strains of oligomers could be significant in phenotypic outcomes. Therefore, it is imperative to determine the ability of strains to faithfully propagate their structure. Here we report fibril propagation of an Aβ42 dodecamer called large fatty acid-derived oligomers (LFAOs). The LFAO oligomeric strain selectively induces acute cerebral amyloid angiopathy (CAA) in neonatally-injected transgenic CRND8 mice. Propagation in-vitro occurs as a three-step process involving the association of LFAO units. LFAO-seeded fibrils possess distinct morphology made of repeating LFAO units that could be regenerated upon sonication. Overall, these data bring forth an important mechanistic perspective into strain-specific propagation of oligomers that has remained elusive thus far.

Reorganisation of Hoxd regulatory landscapes during the evolution of a snake-like body plan.

PubMed

Guerreiro, Isabel; Gitto, Sandra; Novoa, Ana; Codourey, Julien; Nguyen Huynh, Thi Hanh; Gonzalez, Federico; Milinkovitch, Michel C; Mallo, Moises; Duboule, Denis

2016-08-01

Within land vertebrate species, snakes display extreme variations in their body plan, characterized by the absence of limbs and an elongated morphology. Such a particular interpretation of the basic vertebrate body architecture has often been associated with changes in the function or regulation of Hox genes. Here, we use an interspecies comparative approach to investigate different regulatory aspects at the snake HoxD locus. We report that, unlike in other vertebrates, snake mesoderm-specific enhancers are mostly located within the HoxD cluster itself rather than outside. In addition, despite both the absence of limbs and an altered Hoxd gene regulation in external genitalia, the limb-associated bimodal HoxD chromatin structure is maintained at the snake locus. Finally, we show that snake and mouse orthologous enhancer sequences can display distinct expression specificities. These results show that vertebrate morphological evolution likely involved extensive reorganisation at Hox loci, yet within a generally conserved regulatory framework.

Valorization of residual Empty Palm Fruit Bunch Fibers (EPFBF) by microfluidization: production of nanofibrillated cellulose and EPFBF nanopaper.

PubMed

Ferrer, Ana; Filpponen, Ilari; Rodríguez, Alejandro; Laine, Janne; Rojas, Orlando J

2012-12-01

Different cellulose pulps were produced from sulfur-free chemical treatments of Empty Palm Fruit Bunch Fibers (EPFBF), a by-product from palm oil processing. The pulps were microfluidized for deconstruction into nanofibrillated cellulose (NFC) and nanopaper was manufactured by using an overpressure device. The morphological and structural features of the obtained NFCs were characterized via atomic force and scanning electron microscopies. The physical properties as well as the interactions with water of sheets from three different pulps were compared with those of nanopaper obtained from the corresponding NFC. Distinctive chemical and morphological characteristics and ensuing nanopaper properties were generated by the EPFBF fibers. The NFC grades obtained compared favorably with associated materials typically produced from bleached wood fibers. Lower water absorption, higher tensile strengths (107-137 MPa) and elastic modulus (12-18 GPa) were measured, which opens the possibility for valorization of such widely available bioresource. Copyright © 2012 Elsevier Ltd. All rights reserved.

Salivary gland morphology, tissue tropism and the progression of tospovirus infection in Frankliniella occidentalis.

PubMed

Montero-Astúa, Mauricio; Ullman, Diane E; Whitfield, Anna E

2016-06-01

Tomato spotted wilt virus (TSWV) is transmitted by thrips in a propagative manner; however, progression of virus infection in the insect is not fully understood. The goal of this work was to study the morphology and infection of thrips salivary glands. The primary salivary glands (PSG) are complex, with three distinct regions that may have unique functions. Analysis of TSWV progression in thrips revealed the presence of viral proteins in the foregut, midgut, ligaments, tubular salivary glands (TSG), and efferent duct and filament structures connecting the TSG and PSG of first and second instar larvae. The primary site of virus infection shifted from the midgut and TSG in the larvae to the PSG in adults, suggesting that tissue tropism changes with insect development. TSG infection was detected in advance of PSG infection. These findings support the hypothesis that the TSG are involved in trafficking of TSWV to the PSG. Copyright © 2016 Elsevier Inc. All rights reserved.

Monitoring sinew contraction during formation of tissue-engineered fibrin-based ligament constructs.

PubMed

Paxton, Jennifer Z; Wudebwe, Uchena N G; Wang, Anqi; Woods, Daniel; Grover, Liam M

2012-08-01

The ability to study the gross morphological changes occurring during tissue formation is vital to producing tissue-engineered structures of clinically relevant dimensions in vitro. Here, we have used nondestructive methods of digital imaging and optical coherence tomography to monitor the early-stage formation and subsequent maturation of fibrin-based tissue-engineered ligament constructs. In addition, the effect of supplementation with essential promoters of collagen synthesis, ascorbic acid (AA) and proline (P), has been assessed. Contraction of the cell-seeded fibrin gel occurs unevenly within the first 5 days of culture around two fixed anchor points before forming a longitudinal ligament-like construct. AA+P supplementation accelerates gel contraction in the maturation phase of development, producing ligament-like constructs with a higher collagen content and distinct morphology to that of unsupplemented constructs. These studies highlight the importance of being able to control the methods of tissue formation and maturation in vitro to enable the production of tissue-engineered constructs with suitable replacement tissue characteristics for repair of clinical soft-tissue injuries.

Morphology of the oxyurid nematodes Trypanoxyuris (T.) cacajao n. sp. and T. (T.) ucayalii n. sp. from the red uakari monkey Cacajao calvus ucayalii in the Peruvian Amazon.

PubMed

Conga, D F; Giese, E G; Serra-Freire, N M; Bowler, M; Mayor, P

2016-07-01

Cacajao calvus ucayalii (Thomas, 1928) (Primates: Pitheciidae), a subspecies endemic to the Peruvian Amazon, occurs in patchy and sometimes isolated populations in north-eastern Peru and is in a vulnerable situation, mainly due to habitat loss and hunting. This rareness and remote distribution means that, until now, parasitical studies have been limited. Based on optical and scanning electron microscopy of specimens of both sexes, we report two new species of Trypanoxyuris pinworms occurring in the large intestine of the Peruvian red uakari, namely Trypanoxyuris (Trypanoxyuris) cacajao and Trypanoxyuris (Trypanoxyuris) ucayalii. Both species showed a distinct morphology of the lips and cephalic structure. Sexual dimorphism in the lateral alae was observed in both male and the female worms, with ventral ornamentation being shown in the oesophageal teeth. The finding of these new pinworm species highlights the possibility of discovering other species.

Helically structured metal–organic frameworks fabricated by using supramolecular assemblies as templates† †Electronic supplementary information (ESI) available: Detailed TEM images and other extensive figures. See DOI: 10.1039/c4sc03278k Click here for additional data file.

PubMed Central

Wang, Hui; Zhu, Wei; Li, Jian; Tian, Tian; Lan, Yue; Gao, Ning; Wang, Chen; Zhang, Meng; Faul, Charl F. J.

2015-01-01

The controlled formation of MOF-based superstructures with well-defined nanoscale sizes and exquisite morphologies represents a big challenge, but can trigger a new set of properties distinct from their bulk counterparts. Here we report on the use of a self-assembled organic object to template the first example of a nanoscale metal–organic framework (MOF) with a helical morphology. Two prototypical MOFs (HKUST-1 and MIL-100) were used to exemplify the growth of such materials on supramolecular assemblies. Interestingly, it was found that, dependent on the nature of the precursors, not only could well-defined helical MOF nanotubes be facilely fabricated, but novel helical bundle nanostructures could also be formed. These resultant MOF superstructures show additional optical properties and could be used as precursors for the preparation of chiral nanocarbons. PMID:28757993

Reorganisation of Hoxd regulatory landscapes during the evolution of a snake-like body plan

PubMed Central

Guerreiro, Isabel; Gitto, Sandra; Novoa, Ana; Codourey, Julien; Nguyen Huynh, Thi Hanh; Gonzalez, Federico; Milinkovitch, Michel C; Mallo, Moises; Duboule, Denis

2016-01-01

Within land vertebrate species, snakes display extreme variations in their body plan, characterized by the absence of limbs and an elongated morphology. Such a particular interpretation of the basic vertebrate body architecture has often been associated with changes in the function or regulation of Hox genes. Here, we use an interspecies comparative approach to investigate different regulatory aspects at the snake HoxD locus. We report that, unlike in other vertebrates, snake mesoderm-specific enhancers are mostly located within the HoxD cluster itself rather than outside. In addition, despite both the absence of limbs and an altered Hoxd gene regulation in external genitalia, the limb-associated bimodal HoxD chromatin structure is maintained at the snake locus. Finally, we show that snake and mouse orthologous enhancer sequences can display distinct expression specificities. These results show that vertebrate morphological evolution likely involved extensive reorganisation at Hox loci, yet within a generally conserved regulatory framework. DOI: http://dx.doi.org/10.7554/eLife.16087.001 PMID:27476854

Genetic Divergence and Heritability of 42 Coloured Upland Rice Genotypes (Oryzasativa) as Revealed by Microsatellites Marker and Agro-Morphological Traits

PubMed Central

Ahmad, Faiz; Hanafi, Mohamed Musa; Hakim, Md Abdul; Rafii, Mohd Y.; Arolu, Ibrahim Wasiu; Akmar Abdullah, Siti Nor

2015-01-01

Coloured rice genotypes have greater nutritious value and consumer demand for these varieties is now greater than ever. The documentation of these genotypes is important for the improvement of the rice plant. In this study, 42 coloured rice genotypes were selected for determination of their genetic divergence using 25 simple sequence repeat (SSR) primers and 15 agro-morphological traits. Twenty-one out of the 25 SSR primers showed distinct, reproducible polymorphism. A dendrogram constructed using the SSR primers clustered the 42 coloured rice genotypes into 7 groups. Further, principle component analysis showed 75.28% of total variations were explained by the first—three components. All agro-morphological traits showed significant difference at the (p≤0.05) and (p≤0.01) levels. From the dendrogram constructed using the agro-morphological traits, all the genotypes were clustered into four distinct groups. Pearson’s correlation coefficient showed that among the 15 agro-morphological traits, the yield contributing factor had positive correlation with the number of tillers, number of panicles, and panicle length. The heritability of the 15 traits ranged from 17.68 to 99.69%. Yield per plant and harvest index showed the highest value for both heritability and genetic advance. The information on the molecular and agro-morphological traits can be used in rice breeding programmes to improve nutritional value and produce higher yields. PMID:26393807

Major recent and independent changes in levels and patterns of expression have occurred at the b gene, a regulatory locus in maize.

PubMed

Selinger, D A; Chandler, V L

1999-12-21

The b locus encodes a transcription factor that regulates the expression of genes that produce purple anthocyanin pigment. Different b alleles are expressed in distinct tissues, causing tissue-specific anthocyanin production. Understanding how phenotypic diversity is produced and maintained at the b locus should provide models for how other regulatory genes, including those that influence morphological traits and development, evolve. We have investigated how different levels and patterns of pigmentation have evolved by determining the phenotypic and evolutionary relationships between 18 alleles that represent the diversity of b alleles in Zea mays. Although most of these alleles have few phenotypic differences, five alleles have very distinct tissue-specific patterns of pigmentation. Superimposing the phenotypes on the molecular phylogeny reveals that the alleles with strong and distinctive patterns of expression are closely related to alleles with weak expression, implying that the distinctive patterns have arisen recently. We have identified apparent insertions in three of the five phenotypically distinct alleles, and the fourth has unique upstream restriction fragment length polymorphisms relative to closely related alleles. The insertion in B-Peru has been shown to be responsible for its unique expression and, in the other two alleles, the presence of the insertion correlates with the phenotype. These results suggest that major changes in gene expression are probably the result of large-scale changes in DNA sequence and/or structure most likely mediated by transposable elements.

Developmental change in the function of movement systems: transition of the pectoral fins between respiratory and locomotor roles in zebrafish.

PubMed

Hale, Melina E

2014-07-01

An animal may experience strikingly different functional demands on its body's systems through development. One way of meeting those demands is with temporary, stage-specific adaptations. This strategy requires the animal to develop appropriate morphological states or physiological pathways that address transient functional demands as well as processes that transition morphology, physiology, and function to that of the mature form. Recent research on ray-finned (actinopterygian) fishes is a developmental transition in function of the pectoral fin, thereby providing an opportunity to examine how an organism copes with changes in the roles of its morphology between stages of its life history. As larvae, zebrafish alternate their pectoral fins in coordination with the body axis during slow swimming. The movements of their fins do not appear to contribute to the production of thrust or to stability but instead exchange fluid near the body for cutaneous respiration. The morphology of the larval fin includes a simple stage-specific endoskeletal disc overlaid by fan-shaped adductor and abductor muscles. In contrast, the musculoskeletal system of the mature fin consists of a suite of muscles and bones. Fins are extended laterally during slow swimming of the adult, without the distinct, high-amplitude left-right fin alternation of the larval fin. The morphological and functional transition of the pectoral fin occurs through juvenile development. Early in this period, at about 3 weeks post-fertilization, the gills take over respiratory function, presumably freeing the fins for other roles. Kinematic data suggest that the loss of respiratory function does not lead to a rapid switch in patterns of fin movement but rather that both morphology and movement transition gradually through the juvenile stage of development. Studies relating structure to function often focus on stable systems that are arguably well adapted for the roles they play. Examining how animals navigate transitional periods, when the link of structure to function may be less taut, provides insight both into how animals contend with such change and into the developmental pressures that shape mature form and function. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology.

Genetic, Ecological and Morphological Distinctness of the Blue Mussels Mytilus trossulus Gould and M. edulis L. in the White Sea.

PubMed

Katolikova, Marina; Khaitov, Vadim; Väinölä, Risto; Gantsevich, Michael; Strelkov, Petr

2016-01-01

Two blue mussel lineages of Pliocene origin, Mytilus edulis (ME) and M. trossulus (MT), co-occur and hybridize in several regions on the shores of the North Atlantic. The two species were distinguished from each other by molecular methods in the 1980s, and a large amount of comparative data on them has been accumulated since that time. However, while ME and MT are now routinely distinguished by various genetic markers, they tend to be overlooked in ecological studies since morphological characters for taxonomic identification have been lacking, and no consistent habitat differences between lineages have been reported. Surveying a recently discovered area of ME and MT co-occurrence in the White Sea and employing a set of allozyme markers for identification, we address the issue whether ME and MT are true biological species with distinct ecological characteristics or just virtual genetic entities with no matching morphological and ecological identities. We find that: (1) in the White Sea, the occurrence of MT is largely concentrated in harbors, in line with observations from other subarctic regions of Europe; (2) mixed populations of ME and MT are always dominated by purebred individuals, animals classified as hybrids constituting only ca. 18%; (3) in terms of shell morphology, 80% of MT bear a distinct uninterrupted dark prismatic strip under the ligament while 97% of ME lack this character; (4) at sites of sympatry MT is more common on algal substrates while ME mostly lives directly on the bottom. This segregation by the substrate may contribute to maintaining reproductive isolation and decreasing competition between taxa. We conclude that while ME and MT are not fully reproductively isolated, they do represent clearly distinguishable biological, ecological and morphological entities in the White Sea. It remains to be documented whether the observed morphological and ecological differences are of a local character, or whether they have simply been overlooked in other contact zones.

Lecto- and epitypification of Morchella steppicola (Morchellaceae, Pezizales), a morphologically, phylogenetically, and biogeographically distinct member of the Esculenta Clade from central Eurasia

USDA-ARS?s Scientific Manuscript database

The steppe morel, Morchella steppicola, is one of the more iconic species of true morels (Morchellaceae, Pezizales) based on its: 1) distinctive cerebriform pileus with densely packed labyrinthine irregular ridges, 2) genealogically exclusive position as the earliest diverging species lineage within...

Arrasia rostrata (Basidiomycota), a new corticioid genus and species from Italy

Treesearch

Annarosa Bernicchia; Sergio P. Gorj& #243; n; Karen K. Nakasone

2011-01-01

An unusual corticioid species with distinctive large basidiospores that develop a distal refractive rostrum when fully mature is described as new. It grows on living bark of Juniperus phoenicea on the Italian island of Sardinia. Because it is morphologically distinct from any known genus of corticioid fungi, the new genus Arrasia...

Multiple nuclear loci reveal the distinctiveness of the threatened, Neotropical Pinus chiapensis

Treesearch

John Syring; Rafael F. del Castillo; Richard Cronn; Aaron Liston

2007-01-01

Pinus chiapensis is a threatened species of pine from southern Mexico and Guatemala. It was first described as a disjunct variety of P. strobus from the eastern United States and Canada. Subsequent morphological work indicates that P. chinpensis is a distinct species, but this interpretation is controversial. To...

Stomatal cell wall composition: distinctive structural patterns associated with different phylogenetic groups

PubMed Central

Shtein, Ilana; Shelef, Yaniv; Marom, Ziv; Zelinger, Einat; Schwartz, Amnon; Popper, Zoë A.; Bar-On, Benny

2017-01-01

Background and Aims Stomatal morphology and function have remained largely conserved throughout ∼400 million years of plant evolution. However, plant cell wall composition has evolved and changed. Here stomatal cell wall composition was investigated in different vascular plant groups in attempt to understand their possible effect on stomatal function. Methods A renewed look at stomatal cell walls was attempted utilizing digitalized polar microscopy, confocal microscopy, histology and a numerical finite-elements simulation. The six species of vascular plants chosen for this study cover a broad structural, ecophysiological and evolutionary spectrum: ferns (Asplenium nidus and Platycerium bifurcatum) and angiosperms (Arabidopsis thaliana and Commelina erecta) with kidney-shaped stomata, and grasses (angiosperms, family Poaceae) with dumbbell-shaped stomata (Sorghum bicolor and Triticum aestivum). Key Results Three distinct patterns of cellulose crystallinity in stomatal cell walls were observed: Type I (kidney-shaped stomata, ferns), Type II (kidney-shaped stomata, angiosperms) and Type III (dumbbell-shaped stomata, grasses). The different stomatal cell wall attributes investigated (cellulose crystallinity, pectins, lignin, phenolics) exhibited taxon-specific patterns, with reciprocal substitution of structural elements in the end-walls of kidney-shaped stomata. According to a numerical bio-mechanical model, the end walls of kidney-shaped stomata develop the highest stresses during opening. Conclusions The data presented demonstrate for the first time the existence of distinct spatial patterns of varying cellulose crystallinity in guard cell walls. It is also highly intriguing that in angiosperms crystalline cellulose appears to have replaced lignin that occurs in the stomatal end-walls of ferns serving a similar wall strengthening function. Such taxon-specific spatial patterns of cell wall components could imply different biomechanical functions, which in turn could be a consequence of differences in environmental selection along the course of plant evolution. PMID:28158449

Corticostriatal connectivity fingerprints: Probability maps based on resting-state functional connectivity.

PubMed

Jaspers, Ellen; Balsters, Joshua H; Kassraian Fard, Pegah; Mantini, Dante; Wenderoth, Nicole

2017-03-01

Over the last decade, structure-function relationships have begun to encompass networks of brain areas rather than individual structures. For example, corticostriatal circuits have been associated with sensorimotor, limbic, and cognitive information processing, and damage to these circuits has been shown to produce unique behavioral outcomes in Autism, Parkinson's Disease, Schizophrenia and healthy ageing. However, it remains an open question how abnormal or absent connectivity can be detected at the individual level. Here, we provide a method for clustering gross morphological structures into subregions with unique functional connectivity fingerprints, and generate network probability maps usable as a baseline to compare individual cases against. We used connectivity metrics derived from resting-state fMRI (N = 100), in conjunction with hierarchical clustering methods, to parcellate the striatum into functionally distinct clusters. We identified three highly reproducible striatal subregions, across both hemispheres and in an independent replication dataset (N = 100) (dice-similarity values 0.40-1.00). Each striatal seed region resulted in a highly reproducible distinct connectivity fingerprint: the putamen showed predominant connectivity with cortical and cerebellar sensorimotor and language processing areas; the ventromedial striatum cluster had a distinct limbic connectivity pattern; the caudate showed predominant connectivity with the thalamus, frontal and occipital areas, and the cerebellum. Our corticostriatal probability maps agree with existing connectivity data in humans and non-human primates, and showed a high degree of replication. We believe that these maps offer an efficient tool to further advance hypothesis driven research and provide important guidance when investigating deviant connectivity in neurological patient populations suffering from e.g., stroke or cerebral palsy. Hum Brain Mapp 38:1478-1491, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

An ERP study of regular and irregular English past tense inflection.

PubMed

Newman, Aaron J; Ullman, Michael T; Pancheva, Roumyana; Waligura, Diane L; Neville, Helen J

2007-01-01

Compositionality is a critical and universal characteristic of human language. It is found at numerous levels, including the combination of morphemes into words and of words into phrases and sentences. These compositional patterns can generally be characterized by rules. For example, the past tense of most English verbs ("regulars") is formed by adding an -ed suffix. However, many complex linguistic forms have rather idiosyncratic mappings. For example, "irregular" English verbs have past tense forms that cannot be derived from their stems in a consistent manner. Whether regular and irregular forms depend on fundamentally distinct neurocognitive processes (rule-governed combination vs. lexical memorization), or whether a single processing system is sufficient to explain the phenomena, has engendered considerable investigation and debate. We recorded event-related potentials while participants read English sentences that were either correct or had violations of regular past tense inflection, irregular past tense inflection, syntactic phrase structure, or lexical semantics. Violations of regular past tense and phrase structure, but not of irregular past tense or lexical semantics, elicited left-lateralized anterior negativities (LANs). These seem to reflect neurocognitive substrates that underlie compositional processes across linguistic domains, including morphology and syntax. Regular, irregular, and phrase structure violations all elicited later positivities that were maximal over midline parietal sites (P600s), and seem to index aspects of controlled syntactic processing of both phrase structure and morphosyntax. The results suggest distinct neurocognitive substrates for processing regular and irregular past tense forms: regulars depending on compositional processing, and irregulars stored in lexical memory.

Differential progression of structural and functional alterations in distinct retinal ganglion cell types in a mouse model of glaucoma.

PubMed

Della Santina, Luca; Inman, Denise M; Lupien, Caroline B; Horner, Philip J; Wong, Rachel O L

2013-10-30

Intraocular pressure (IOP) elevation is a principal risk factor for glaucoma. Using a microbead injection technique to chronically raise IOP for 15 or 30 d in mice, we identified the early changes in visual response properties of different types of retinal ganglion cells (RGCs) and correlated these changes with neuronal morphology before cell death. Microbead-injected eyes showed reduced optokinetic tracking as well as cell death. In such eyes, multielectrode array recordings revealed that four RGC types show diverse alterations in their light responses upon IOP elevation. OFF-transient RGCs exhibited a more rapid decline in both structural and functional organizations compared with other RGCs. In contrast, although the light-evoked responses of OFF-sustained RGCs were perturbed, the dendritic arbor of this cell type remained intact. ON-transient and ON-sustained RGCs had normal functional receptive field sizes but their spontaneous and light-evoked firing rates were reduced. ON- and OFF-sustained RGCs lost excitatory synapses across an otherwise structurally normal dendritic arbor. Together, our observations indicate that there are changes in spontaneous activity and light-evoked responses in RGCs before detectable dendritic loss. However, when dendrites retract, we found corresponding changes in receptive field center size. Importantly, the effects of IOP elevation are not uniformly manifested in the structure and function of diverse RGC populations, nor are distinct RGC types perturbed within the same time-frame by such a challenge.

Field Investigation of Flow Structure and Channel Morphology at Confluent-Meander Bends

NASA Astrophysics Data System (ADS)

Riley, J. D.; Rhoads, B. L.

2007-12-01

The movement of water and sediment through drainage networks is inevitably influenced by the convergence of streams and rivers at channel confluences. These focal components of fluvial systems produce a complex hydrodynamic environment, where rapid changes in flow structure and sediment transport occur to accommodate the merging of separate channel flows. The inherent geometric and hydraulic change at confluences also initiates the development of distinct geomorphic features, reflected in the bedform and shape of the channel. An underlying assumption of previous experimental and theoretical models of confluence dynamics has been that converging streams have straight channels with angular configurations. This generalized conceptualization was necessary to establish confluence planform as symmetrical or asymmetrical and to describe subsequent flow structure and geomorphic features at confluences. However, natural channels, particularly those of meandering rivers, curve and bend. This property and observation of channel curvature at natural junctions have led to the hypothesis that natural stream and river confluences tend to occur on the concave outer bank of meander bends. The resulting confluence planform, referred to as a confluent-meander bend, was observed over a century ago but has received little scientific attention. This paper examines preliminary data on three-dimensional flow structure and channel morphology at two natural confluent-meander bends of varying size and with differing tributary entrance locations. The large river confluence of the Vermilion River and Wabash River in west central Indiana and the comparatively small junction of the Little Wabash River and Big Muddy Creek in southeastern Illinois are the location of study sites for field investigation. Measurements of time-averaged three-dimensional velocity components were obtained at these confluences with an acoustic Doppler current profiler for flow events with differing momentum ratios. Bed and channel morphology were also surveyed with a digital fathometer to document geomorphic change. Preliminary analysis of the velocity data reveals the presence of a well-defined shear layer between the converging flows and secondary circulation in the main channel. The tributary channel appears to oppose high velocity flow directed toward the outer bank by centrifugal acceleration through the meander bend of the main channel, thereby diminishing erosion along the cut bank and possibly stabilizing the meander bend channel. The flow structure and channel morphology of the study sites are compared to consider the effect of spatial scale and geometric characteristics on confluent-meander bend dynamics.

Interrelated structures of the transport shock and collisional relaxation layer in a multitemperature, multilevel ionized gas

NASA Technical Reports Server (NTRS)

Vinolo, A. R.; Clarke, J. H.

1972-01-01

The gas dynamic structures of the transport shock and the downstream collisional relaxation layer are evaluated for partially ionized monatomic gases. Elastic and inelastic collisional nonequilibrium effects are taken into consideration. Three electronic levels are accounted for in the microscopic model of the atom. Nonequilibrium processes with respect to population of levels and species plus temperature are considered. By using an asymptotic technique the shock morphology is found on a continuum flow basis. The asymptotic procedure gives two distinct layers in which the nonequilibrium effects to be considered are different. A transport shock appears as the inner solution to an outer collisional relaxation layer in which the gas reaches local equilibrium. A family of numerical examples is displayed for different flow regimes. Argon and helium models are used in these examples.

Structural deformation at the Flynn Creek impact crater, Tennessee - A preliminary report on deep drilling

NASA Technical Reports Server (NTRS)

Roddy, D. J.

1979-01-01

The geologic and core drilling studies described in the present paper show that the Flynn Creek crater has such distinctive morphological features as a broad flat hummocky floor; large central peak; locally terraced crater walls; uplifted, as well as flat-lying rim segments; and a surrounding ejecta blanket. The major structural features include a shallow depth of total brecciation and excavation as compared with apparent crater diameter; a thin breccia lens underlain by a thin zone of disrupted strata; concentric ring fault zones in inner rim, beneath crater wall, and outer crater floor regions; a large central uplift underlain by a narrow dipping zone of deeply disrupted strata; faulted, folded, brecciated, and fractured rim strata; and uplifted rim strata, which dip away from the crater, and flat-lying rim strata, which terminate as inward dipping rocks.

Comparison of the brain development trajectory between Chinese and U.S. children and adolescents

PubMed Central

Xie, Wanze; Richards, John E.; Lei, Du; Lee, Kang; Gong, Qiyong

2015-01-01

This current study investigated brain development of Chinese and American children and adolescents from 8 to 16 years of age using structural magnetic resonance imaging (MRI) techniques. Analyses comparing Chinese and U.S. children brain/head MR images were performed to explore similarities and differences in the trajectory of brain development between these two groups. Our results revealed regional and age differences in both brain/head morphological and tissue level development between Chinese and U.S. children. Chinese children's brains and heads were shorter, wider, and taller than those of U.S. children. There were significant differences in the gray matter (GM) and white matter (WM) intensity between the two nationalities. Development trajectories for cerebral volume, GM, and several key brain structures were also distinct between these two populations. PMID:25698941

Minimal Similarity between Biogeographic Patterns of Morphological Disparity and Taxonomic Richness in Extant Coccolithophores

NASA Astrophysics Data System (ADS)

Villarosa Garcia, M.

2016-02-01

Morphologic disparity, carries both an ecological and evolutionary signal and, where practical, might bridge ecological processes observed in modern seas with macroevolutionary processes observed in the fossil record, complementing taxonomic diversity studies. I compare the biogeography of morphologic disparity and taxonomic richness in extant coccolithophores to understand the role of environmental conditions in their spatial partitioning. I analyze 112 traits in 125 species and measure geographic extent as the occupation of pelagic biogeographic provinces (sensu Spalding et al. 2012). In the modern ocean, coccolithophorid species richness increases towards the equator, peaking in the subtropics, and certain biomes harbor more species. In contrast, their morphologic disparity does not vary across latitudes and biomes, yielding similar values of variance and mean pair-wise distances. Disparity is weakly correlated to richness across clades and biomes (no clear latitudinal pattern). I also study the morphological breadth of clades in a multivariate morphospace plotted as principal coordinate axes (PCO). Clades have distinct centroids but show some overlap in volume. However, they are completely separate when using canonical variates analysis (CVA) on these PCO axes. The centroids of latitudinal groups are closely spaced, and overlap in morphospace, but again separate with CVA. However biome groups can't be distinguished using PCO or CVA. Although clades with the most species tend to have high disparity, most clades are found in every region yielding similar group disparities. Despite the fact that taxonomic diversity is spatially partitioned on the globe, morphologic disparity has no such organization. Past studies using marine gastropods (Roy et al. 2001; McClain 2005), cuttlefish (Neige 2003), and birds (Jønsson et al. 2015) also find minimal support for a biogeographic structure of disparity, highlighting the profound nature of this differential response.

Stress-driven buckling patterns in spheroidal core/shell structures.

PubMed

Yin, Jie; Cao, Zexian; Li, Chaorong; Sheinman, Izhak; Chen, Xi

2008-12-09

Many natural fruits and vegetables adopt an approximately spheroidal shape and are characterized by their distinct undulating topologies. We demonstrate that various global pattern features can be reproduced by anisotropic stress-driven buckles on spheroidal core/shell systems, which implies that the relevant mechanical forces might provide a template underpinning the topological conformation in some fruits and plants. Three dimensionless parameters, the ratio of effective size/thickness, the ratio of equatorial/polar radii, and the ratio of core/shell moduli, primarily govern the initiation and formation of the patterns. A distinct morphological feature occurs only when these parameters fall within certain ranges: In a prolate spheroid, reticular buckles take over longitudinal ridged patterns when one or more parameters become large. Our results demonstrate that some universal features of fruit/vegetable patterns (e.g., those observed in Korean melons, silk gourds, ribbed pumpkins, striped cavern tomatoes, and cantaloupes, etc.) may be related to the spontaneous buckling from mechanical perspectives, although the more complex biological or biochemical processes are involved at deep levels.

Distinct ice patterns on solid surfaces with various wettabilities

PubMed Central

Liu, Jie; Zhu, Chongqin; Liu, Kai; Jiang, Ying; Song, Yanlin; Francisco, Joseph S.; Zeng, Xiao Cheng; Wang, Jianjun

2017-01-01

No relationship has been established between surface wettability and ice growth patterns, although ice often forms on top of solid surfaces. Here, we report experimental observations obtained using a process specially designed to avoid the influence of nucleation and describe the wettability-dependent ice morphology on solid surfaces under atmospheric conditions and the discovery of two growth modes of ice crystals: along-surface and off-surface growth modes. Using atomistic molecular dynamics simulation analysis, we show that these distinct ice growth phenomena are attributable to the presence (or absence) of bilayer ice on solid surfaces with different wettability; that is, the formation of bilayer ice on hydrophilic surface can dictate the along-surface growth mode due to the structural match between the bilayer hexagonal ice and the basal face of hexagonal ice (ice Ih), thereby promoting rapid growth of nonbasal faces along the hydrophilic surface. The dramatically different growth patterns of ice on solid surfaces are of crucial relevance to ice repellency surfaces. PMID:29073045

Distinct ice patterns on solid surfaces with various wettabilities.

PubMed

Liu, Jie; Zhu, Chongqin; Liu, Kai; Jiang, Ying; Song, Yanlin; Francisco, Joseph S; Zeng, Xiao Cheng; Wang, Jianjun

2017-10-24

No relationship has been established between surface wettability and ice growth patterns, although ice often forms on top of solid surfaces. Here, we report experimental observations obtained using a process specially designed to avoid the influence of nucleation and describe the wettability-dependent ice morphology on solid surfaces under atmospheric conditions and the discovery of two growth modes of ice crystals: along-surface and off-surface growth modes. Using atomistic molecular dynamics simulation analysis, we show that these distinct ice growth phenomena are attributable to the presence (or absence) of bilayer ice on solid surfaces with different wettability; that is, the formation of bilayer ice on hydrophilic surface can dictate the along-surface growth mode due to the structural match between the bilayer hexagonal ice and the basal face of hexagonal ice (ice I h ), thereby promoting rapid growth of nonbasal faces along the hydrophilic surface. The dramatically different growth patterns of ice on solid surfaces are of crucial relevance to ice repellency surfaces. Published under the PNAS license.

Biologically distinct subsets of nevi

PubMed Central

ROGERS, Tova; MARINO, Maria L.; RACITI, Patricia; JAIN, Manu; BUSAM, Klaus J.; MARCHETTI, Michael A.; MARGHOOB, Ashfaq A.

2017-01-01

Melanocytic nevi (MN) encompass a range of benign tumors with varying microscopic and macroscopic features. Their development is a multifactorial process under genetic and environmental influences. The clinical importance of MN lies in distinguishing them from melanoma and in recognizing their associations with melanoma risk and cancer syndromes. Historically, the distinction between the different types of MN, as well as between MN and melanoma, was based on clinical history, gross morphology, and histopathological features. While histopathology with clinical correlation remains the gold standard for differentiating and diagnosing melanocytic lesions, in some cases, this may not be possible. The use of dermoscopy has allowed for the assessment of subsurface skin structures and has contributed to the clinical evaluation and classification of MN. Genetic profiling, while still in its early stages, has the greatest potential to refine the classification of MN by clarifying their developmental processes, biological behaviors, and relationships to melanoma. Here we review the most salient clinical, dermoscopic, histopathological, and genetic features of different MN subgroups. PMID:27119653

Genetic diversity analysis of Capparis spinosa L. populations by using ISSR markers.

PubMed

Liu, C; Xue, G P; Cheng, B; Wang, X; He, J; Liu, G H; Yang, W J

2015-12-09

Capparis spinosa L. is an important medicinal species in the Xinjiang Province of China. Ten natural populations of C. spinosa from 3 locations in North, Central, and South Xinjiang were studied using morphological trait inter simple sequence repeat (ISSR) molecular markers to assess the genetic diversity and population structure. In this study, the 10 ISSR primers produced 313 amplified DNA fragments, with 52% of fragments being polymorphic. Unweighted pair-group method with arithmetic average (UPGMA) cluster analysis indicated that 10 C. spinosa populations were clustered into 3 geographically distinct groups. The Nei gene of C. spinosa populations in different regions had Diversity and Shannon's information index ranges of 0.1312-0.2001 and 0.1004-0.1875, respectively. The 362 markers were used to construct the dendrogram based on the UPGMA cluster analysis. The dendrogram indicated that 10 populations of C. spinosa were clustered into 3 geographically distinct groups. The results showed these genotypes have high genetic diversity, and can be used for an alternative breeding program.

Microsatellite markers identify three lineages of Phytophthora ramorum in US nurseries, yet single lineages in US forest and European nursery populations.

PubMed

Ivors, K; Garbelotto, M; Vries, I D E; Ruyter-Spira, C; Te Hekkert, B; Rosenzweig, N; Bonants, P

2006-05-01

Analysis of 12 polymorphic simple sequence repeats identified in the genome sequence of Phytophthora ramorum, causal agent of 'sudden oak death', revealed genotypic diversity to be significantly higher in nurseries (91% of total) than in forests (18% of total). Our analysis identified only two closely related genotypes in US forests, while the genetic structure of populations from European nurseries was of intermediate complexity, including multiple, closely related genotypes. Multilocus analysis determined populations in US forests reproduce clonally and are likely descendants of a single introduced individual. The 151 isolates analysed clustered in three clades. US forest and European nursery isolates clustered into two distinct clades, while one isolate from a US nursery belonged to a third novel clade. The combined microsatellite, sequencing and morphological analyses suggest the three clades represent distinct evolutionary lineages. All three clades were identified in some US nurseries, emphasizing the role of commercial plant trade in the movement of this pathogen.

Spatial localization of excitons and charge carriers in hybrid perovskite thin films

DOE PAGES

Simpson, Mary Jane; Doughty, Benjamin; Yang, Bin; ...

2015-07-21

The fundamental photophysics underlying the remarkably high power conversion efficiency of organic-inorganic hybrid perovskite-based solar cells has been increasingly studied using complementary spectroscopic techniques. The spatially heterogeneous polycrystalline morphology of the photoactive layers owing to the presence of distinct crystalline grains has been generally neglected in optical measurements and therefore the reported results are typically averaged over hundreds or even thousands of such grains. Here, we apply femtosecond transient absorption microscopy to spatially and temporally probe ultrafast electronic excited-state dynamics in pristine methylammonium lead tri-iodide (CH 3NH 3PbI 3) thin films and composite structures. We found that the electronic excited-statemore » relaxation kinetics are extremely sensitive to the sample location probed, which was manifested by position-dependent decay timescales and transient signals. As a result, analysis of transient absorption kinetics acquired at distinct spatial positions enabled us to identify contributions of excitons and free charge carriers.« less

Morphology and histology of male and female reproductive systems in the inseminating species Scoloplax distolothrix (Ostariophysi: Siluriformes: Scoloplacidae).

PubMed

Spadella, Maria Angélica; Oliveira, Claudio; Quagio-Grassiotto, Irani

2008-09-01

The morphology and histology of male and female reproductive systems were examined in Scoloplax distolothrix. Internal insemination was documented in this species by the presence of sperm within the ovaries. Mature males and females have elongated genital papillae, exhibiting a tubular shape in males and a plain heart-shape with two median protuberances in females. The testes are two elongated structures that converge ventrally, under the intestine, towards the genital papilla. They are joined at the caudal end, forming an ovoid single chamber for sperm storage. Secretory regions were not observed. In the lumen of the testicular tubules, spermatozoa can be tightly packed along their lengths, but do not constitute a spermatozeugmata. The lumen of the sperm storage chamber and spermatic duct are filled with free spermatozoa without the accompanying secretions. The ovaries are bird-wing shaped, saccular structures that converge ventrally under the intestine, towards the genital papilla. They are joined at the caudal end, forming a tubular chamber possibly destined for oocyte storage. An oviduct with an irregular outline connects the chamber to the tubular region of the genital papilla. No distinct sperm storage structure was found in the ovaries. The unique male and female genital papillae suggest that these structures are associated with the reproductive mode in scoloplacids, representing evidence for insemination. The occurrence of free spermatozoa, without the accompanying secretions and not arranged in a spermatozeugmata can be associated with the presence of a tubular male genital papilla for sperm transfer to the female genital tract. This reinforces the idea that sperm packets are not necessary for all inseminating species. The male reproductive system in scoloplacids is very different from that in auchenipterids, a second catfish family with insemination, which indicates that the occurrence of insemination is not connected to the internal morphology of reproductive organs.

Genetic diversity and population structure of an Italian landrace of runner bean (Phaseolus coccineus L.): inferences for its safeguard and on-farm conservation.

PubMed

Mercati, F; Catarcione, G; Paolacci, A R; Abenavoli, M R; Sunseri, F; Ciaffi, M

2015-08-01

The landraces are considered important sources of valuable germplasm for breeding activities to face climatic changes as well as to satisfy the requirement of new varieties for marginal areas. Runner bean (Phaseolus coccineus L.) is one of the most cultivated Phaseolus species worldwide, but few studies have been addressed to assess the genetic diversity and structure within and among landrace populations. In the present study, 20 different populations of a runner bean landrace from Central Italy named "Fagiolone," together with 41 accessions from Italy and Mesoamerica, were evaluated by using 14 nuclear SSRs to establish its genetic structure and distinctiveness. Results indicated that "Fagiolone" landrace can be considered as a dynamic evolving open-pollinated population that shows a significant level of genetic variation, mostly detected within populations, and the presence of two main genetic groups, of which one distinguished from other Italian runner bean landraces. Results highlighted also a relevant importance of farmers' management practices able to influence the genetic structure of this landrace, in particular the seed exchanges and selection, and the past introduction in cultivation of landraces/cultivars similar to seed morphology, but genetically rather far from "Fagiolone." The most suitable on-farm strategies for seed collection, conservation and multiplication will be defined based on our results, as a model for threatened populations of other allogamous crop species. STRUCTURE and phylogenetic analyses indicated that Mesoamerican accessions and Italian landraces belong to two distinct gene pools confirming the hypothesis that Europe could be considered a secondary diversification center for P. coccineus.

Evolutionary and ecological forces influencing population diversification in Bornean montane passerines.

PubMed

Chua, Vivien L; Smith, Brian Tilston; Burner, Ryan C; Rahman, Mustafa Abdul; Lakim, Maklarin; Prawiradilaga, Dewi M; Moyle, Robert G; Sheldon, Frederick H

2017-08-01

The mountains of Borneo are well known for their high endemicity and historical role in preserving Southeast Asian rainforest biodiversity, but the diversification of populations inhabiting these mountains is poorly studied. Here we examine the genetic structure of 12 Bornean montane passerines by comparing complete mtDNA ND2 gene sequences of populations spanning the island. Maximum likelihood and Bayesian phylogenetic trees and haplotype networks are examined for common patterns that might signal important historical events or boundaries to dispersal. Morphological and ecological characteristics of each species are also examined using phylogenetic generalized least-squares (PGLS) for correlation with population structure. Populations in only four of the 12 species are subdivided into distinct clades or haplotype groups. Although this subdivision occurred at about the same time in each species (ca. 0.6-0.7Ma), the spatial positioning of the genetic break differs among the species. In two species, northeastern populations are genetically divergent from populations elsewhere on the island. In the other two species, populations in the main Bornean mountain chain, including the northeast, are distinct from those on two isolated peaks in northwestern Borneo. We suggest different historical forces played a role in shaping these two distributions, despite commonality in timing. PGLS analysis showed that only a single characteristic-hand-wing index-is correlated with population structure. Birds with longer wings, and hence potentially more dispersal power, have less population structure. To understand historical forces influencing montane population structure on Borneo, future studies must compare populations across the entirety of Sundaland. Copyright © 2017 Elsevier Inc. All rights reserved.

Genetic variation in horizontally transmitted fungal endophytes of pine needles reveals population structure in cryptic species.

PubMed

Oono, Ryoko; Lutzoni, François; Arnold, A Elizabeth; Kaye, Laurel; U'Ren, Jana M; May, Georgiana; Carbone, Ignazio

2014-08-01

• Fungal endophytes comprise one of the most ubiquitous groups of plant symbionts, inhabiting healthy leaves and stems of all major lineages of plants. Together, they comprise immense species richness, but little is known about the fundamental processes that generate their diversity. Exploration of their population structure is needed, especially with regard to geographic distributions and host affiliations.• We take a multilocus approach to examine genetic variation within and among populations of Lophodermium australe, an endophytic fungus commonly associated with healthy foliage of pines in the southeastern United States. Sampling focused on two pine species ranging from montane to coastal regions of North Carolina and Virginia.• Our sampling revealed two genetically distinct groups within Lophodermium australe. Our analysis detected less than one migrant per generation between them, indicating that they are distinct species. The species comprising the majority of isolates (major species) demonstrated a panmictic structure, whereas the species comprising the minority of isolates (cryptic species) demonstrated isolation by distance. Distantly related pine species hosted the same Lophodermium species, and host species did not influence genetic structure.• We present the first evidence for isolation by distance in a foliar fungal endophyte that is horizontally transmitted. Cryptic species may be common among microbial symbionts and are important to delimit when exploring their genetic structure and microevolutionary processes. The hyperdiversity of endophytic fungi may be explained in part by cryptic species without apparent ecological and morphological differences as well as genetic diversification within rare fungal species across large spatial scales. © 2014 Botanical Society of America, Inc.

NanoSIMS Reveals New Structural and Elemental Signatures of Early Life

NASA Technical Reports Server (NTRS)

Oehler, Dorothy Z.; Mostefaoui, Smail; Meibom, Anders; Selo, Madeleine; Robert, Francois; McKay, David S.

2006-01-01

The young technology of NanoSIMS is unlocking new information from organic matter in ancient sediments. We have used this technique to characterize sub-micron scale element composition of Proterozoic organics that are clearly biogenic as a guide for interpreting problematic structures in terrestrial or extraterrestrial samples. We used the NanoSIMS 50 of the National Museum of Natural History in Paris to map carbon, nitrogen (as CN), and sulfur in organic structures from the approximately 0.8 Ga Bitter Springs Formation. We analyzed spheroidal and filamentous microfossils as well as organic laminae that appeared amorphous by optical and scanning electron microscopy. In clear-cut microfossils, a coincidence between optical images and NanoSIMS element maps suggests a biological origin for the mapped carbon, sulfur, and nitrogen; this conclusion is supported by high resolution NanoSIMS maps showing identical spatial distributions of C, CN and S. High resolution images also demonstrate distinctive nano structure of the filaments and spheroids. In the amorphous laminae, NanoSIMS reveals morphologies reminiscent of compressed microfossils. Distinct CN/C ratios of the spheroids, filaments, and laminae may reflect their biological precursors (cell walls, cyanobacterial sheaths, and microbial communities/biofilms, respectively). Similar amorphous laminae comprise a preponderance of the organic matter in many Precambrian deposits. Thus it is possible that NanoSIMS will provide fresh insight into a large body of previously uninterpretable material. Additionally, NanoSIMS analysis may establish new biosignatures that will be helpful for assessing the origin and biogenicity of controversial Archean structures and any organic materials that may occur in Martian or other extraterrestrial samples.

Morphology and Kinematics of Filaments in the Serpens and Perseus Molecular Clouds

NASA Astrophysics Data System (ADS)

Dhabal, Arnab; Mundy, Lee G.; Rizzo, Maxime J.; Storm, Shaye; Teuben, Peter

2018-02-01

We present H13CO+ (J = 1–0) and HNC (J = 1–0) maps of regions in Serpens South, Serpens Main, and NGC 1333 containing filaments. We also observe the Serpens regions using H13CN (J = 1–0). These dense gas tracer molecular line observations carried out with CARMA have an angular resolution of ∼7″, a spectral resolution of ∼0.16 km s‑1, and a sensitivity of 50–100 mJy beam‑1. Although the large-scale structure compares well with the Herschel dust continuum maps, we resolve finer structure within the filaments identified by Herschel. The H13CO+ emission distribution agrees with the existing CARMA N2H+ (J = 1–0) maps, so they trace the same morphology and kinematics of the filaments. The H13CO+ maps additionally reveal that many regions have multiple structures partially overlapping in the line of sight. In two regions, the velocity differences are as high as 1.4 km s‑1. We identify eight filamentary structures having typical widths of 0.03–0.08 pc in these tracers. At least 50% of the filamentary structures have distinct velocity gradients perpendicular to their major axis, with average values in the range of 4–10 km s‑1 pc‑1. These findings are in support of the theoretical models of filament formation by 2D inflow in the shock layer created by colliding turbulent cells. We also find evidence of velocity gradients along the length of two filamentary structures; the gradients suggest that these filaments are inflowing toward the cloud core.

Neuroarchitecture and neuroanatomy of the Drosophila central complex: A GAL4-based dissection of protocerebral bridge neurons and circuits

PubMed Central

Wolff, Tanya; Iyer, Nirmala A; Rubin, Gerald M

2015-01-01

Insects exhibit an elaborate repertoire of behaviors in response to environmental stimuli. The central complex plays a key role in combining various modalities of sensory information with an insect's internal state and past experience to select appropriate responses. Progress has been made in understanding the broad spectrum of outputs from the central complex neuropils and circuits involved in numerous behaviors. Many resident neurons have also been identified. However, the specific roles of these intricate structures and the functional connections between them remain largely obscure. Significant gains rely on obtaining a comprehensive catalog of the neurons and associated GAL4 lines that arborize within these brain regions, and on mapping neuronal pathways connecting these structures. To this end, small populations of neurons in the Drosophila melanogaster central complex were stochastically labeled using the multicolor flip-out technique and a catalog was created of the neurons, their morphologies, trajectories, relative arrangements, and corresponding GAL4 lines. This report focuses on one structure of the central complex, the protocerebral bridge, and identifies just 17 morphologically distinct cell types that arborize in this structure. This work also provides new insights into the anatomical structure of the four components of the central complex and its accessory neuropils. Most strikingly, we found that the protocerebral bridge contains 18 glomeruli, not 16, as previously believed. Revised wiring diagrams that take into account this updated architectural design are presented. This updated map of the Drosophila central complex will facilitate a deeper behavioral and physiological dissection of this sophisticated set of structures. J. Comp. Neurol. 523:997–1037, 2015. © 2014 Wiley Periodicals, Inc. PMID:25380328

Chryse Planitia, Mars: Topographic configuration, outflow channel continuity and sequence, and tests for hypothesized ancient bodies of water using Mars Orbiter Laser Altimeter (MOLA) data

NASA Astrophysics Data System (ADS)

Ivanov, M. A.; Head, J. W.

2001-02-01

Many of the largest and most prominent outflow channels on Mars debouch into Chryse Planitia. Pre-Mars Global Surveyor topographic data show Chryse to be a closed depression almost 2000 km in diameter. New Mars Orbiter Laser Altimeter (MOLA) data reveal the following: (1) Chryse is not a locally closed basin but instead opens into the North Polar basin. (2) The highly distinctive morphology of the six largest predominantly Hesperian-aged channels (Kasei, Maja, Simud, Tiu, Ares, and Mawrth) disappears into the northern lowlands at average elevations that all occur within less than ~170 m of a mean elevation of -3742(SD=153m), over a lateral distance in excess of 2500 km. (3) The elevations where the distinctive morphology of each channel disappears all fall within ~190 m of Contact 2, a boundary mapped by Parker et al. [1993] and interpreted to represent an ancient shoreline, and the mean elevation values of Contact 2 and circum-Chryse channel termini fall within 18 m of each other. In contrast, the termini of seven later Amazonian-aged channels emerging from Elysium into Utopia Planitia are spread over a vertical range of >1500 m. (4) Topographic evidence of the continuation of some of the outflow channels can be observed for distances of 250-450 km into the North Polar basin, but the morphology is subdued and distinctly different. (5) The nature of this less distinctive topography and its crosscutting relationships show that Simud and Tiu are likely to represent the youngest activity (specifically crosscutting Ares Valles). (6) The distinctive change in channel morphology is consistent with rapid loss of energy encountered at base level (subaerial/submarine boundary) and emplacement into a shallow submarine environment. Channel characteristics, lack of distinctive deltas or lobes, and continuation of subdued channel morphology suggest hyperpychnal flow and the possibility of density/turbidity currents. Estimates of the volumes of individual channel events are wide-ranging. The minimum volume estimates of Carr [1996] suggest that 46 such events would be required to fill the basin to the level of Contact 2 and thus that the channels may have emptied into an existing standing body of water. Volume estimates of Baker et al. [1991] assume that single individual events may have filled the basin to the level of Contact 2, thus requiring significant water loss between events and refilling during subsequent events to essentially the same level. In both end-member cases these observations are consistent with the presence of large standing bodies of water in the northern lowlands in Hesperian-Early Amazonian times.

In-Depth View of the Structure and Growth of SnO2 Nanowires and Nanobrushes.

PubMed

Stuckert, Erin P; Geiss, Roy H; Miller, Christopher J; Fisher, Ellen R

2016-08-31

Strategic application of an array of complementary imaging and diffraction techniques is critical to determine accurate structural information on nanomaterials, especially when also seeking to elucidate structure-property relationships and their effects on gas sensors. In this work, SnO2 nanowires and nanobrushes grown via chemical vapor deposition (CVD) displayed the same tetragonal SnO2 structure as revealed via powder X-ray diffraction bulk crystallinity data. Additional characterization using a range of electron microscopy imaging and diffraction techniques, however, revealed important structure and morphology distinctions between the nanomaterials. Tailoring scanning transmission electron microscopy (STEM) modes combined with transmission electron backscatter diffraction (t-EBSD) techniques afforded a more detailed view of the SnO2 nanostructures. Indeed, upon deeper analysis of individual wires and brushes, we discovered that, despite a similar bulk structure, wires and brushes grew with different crystal faces and lattice spacings. Had we not utilized multiple STEM diffraction modes in conjunction with t-EBSD, differences in orientation related to bristle density would have been overlooked. Thus, it is only through a methodical combination of several structural analysis techniques that precise structural information can be reliably obtained.

Morphological, morphometrical and molecular (CO1 and ITS) analysis of the rotifer Asplanchna brightwellii from selected freshwater bodies in Central Mexico.

PubMed

Jiménez-Contreras, Jorge; Sarma, S S S; Calderón-Torres, Marissa; Nandini, S

2013-11-01

We evaluated different strains of the rotifer Asplanchna brightwellii collected from central Mexico using morphology, morphometry and molecular tools (CO1 and ITS). Three distinct clonal populations from each of the 3 regions (Mexico City, State of Mexico and State of Guerrero) were established under laboratory conditions. For a given waterbody, morphometric comparisons within the populations of A. brightwellii showed almost stable measurements of trophi and with no statistically significant differences among them (p > 0.05). However, asplanchnid body length and width as well as the cyst diameter varied significantly depending on the waterbody from which A. brightwellii was collected. The smallest adults (about 700 microm) were from Valerio Trujano lake (Guerrero State) samples while the largest were from Xochimilco lake. Similar tendencies were reflected in the diameter of resting eggs. In addition, morphologically the cysts of A. brightwellii from the three waterbodies showed slightly different pattern. The number of globular structures on the surface of cysts was smaller for Valerio Trujano strain, while these were larger and less numerous for both Xochimilco and Zumpango strains. The ITS region tree displayed two groups Xochimilco and Valerio Trujano -Zumpango, this analysis did not reflect the morphological grouping; on the contrary the CO1 gene tree separated the populations according to morphological clusters and location (Xochimilco, Valerio Trujano and Zumpango lakes). When the tree was built using the combination of both ITS and CO1 sequences, the phylogenetic relationships observed on CO1 gene were consistent; but showed differences with the relationships observed on ITS region tree (only two groups).

Carbon materials-functionalized tin dioxide nanoparticles toward robust, high-performance nitrogen dioxide gas sensor.

PubMed

Zhang, Rui; Liu, Xiupeng; Zhou, Tingting; Wang, Lili; Zhang, Tong

2018-08-15

Carbon (C) materials, which process excellent electrical conductivity and high carrier mobility, are promising sensing materials as active units for gas sensors. However, structural agglomeration caused by chemical processes results in a small resistance change and low sensing response. To address the above issues, structure-derived carbon-coated tin dioxide (SnO 2 ) nanoparticles having distinct core-shell morphology with a 3D net-like structure and highly uniform size are prepared by careful synthesis and fine structural design. The optimum carbon-coated SnO 2 nanoparticles (SnO 2 /C)-based gas sensor exhibits a low working temperature, excellent selectivity and fast response-recovery properties. In addition, the SnO 2 /C-based gas sensor can maintain a sensitivity to nitrogen dioxide (NO 2 ) of 3 after being cycled 4 times at 140 °C for, suggesting its good long-term stability. The structural integrity, good synergistic properties, and high gas-sensing performance of SnO 2 /C render it a promising sensing material for advanced gas sensors. Copyright © 2018 Elsevier Inc. All rights reserved.

Labyrinths, columns and cavities: new internal features of pollen grain walls in the Acanthaceae detected by FIB-SEM.

PubMed

House, Alisoun; Balkwill, Kevin

2016-03-01

External pollen grain morphology has been widely used in the taxonomy and systematics of flowering plants, especially the Acanthaceae which are noted for pollen diversity. However internal pollen wall features have received far less attention due to the difficulty of examining the wall structure. Advancing technology in the field of microscopy has made it possible, with the use of a focused ion beam-scanning electron microscope (FIB-SEM), to view the structure of pollen grain walls in far greater detail and in three dimensions. In this study the wall structures of 13 species from the Acanthaceae were investigated for features of potential systematic relevance. FIB-SEM was applied to obtain precise cross sections of pollen grains at selected positions for examining the wall ultrastructure. Exploratory studies of the exine have thus far identified five basic structural types. The investigations also show that similar external pollen wall features may have a distinctly different internal structure. FIB-SEM studies have revealed diverse internal pollen wall features which may now be investigated for their systematic and functional significance.

Flow-Directed Crystallization for Printed Electronics.

PubMed

Qu, Ge; Kwok, Justin J; Diao, Ying

2016-12-20

The solution printability of organic semiconductors (OSCs) represents a distinct advantage for materials processing, enabling low-cost, high-throughput, and energy-efficient manufacturing with new form factors that are flexible, stretchable, and transparent. While the electronic performance of OSCs is not comparable to that of crystalline silicon, the solution processability of OSCs allows them to complement silicon by tackling challenging aspects for conventional photolithography, such as large-area electronics manufacturing. Despite this, controlling the highly nonequilibrium morphology evolution during OSC printing remains a challenge, hindering the achievement of high electronic device performance and the elucidation of structure-property relationships. Many elegant morphological control methodologies have been developed in recent years including molecular design and novel processing approaches, but few have utilized fluid flow to control morphology in OSC thin films. In this Account, we discuss flow-directed crystallization as an effective strategy for controlling the crystallization kinetics during printing of small molecule and polymer semiconductors. Introducing the concept of flow-directed crystallization to the field of printed electronics is inspired by recent advances in pharmaceutical manufacturing and flow processing of flexible-chain polymers. Although flow-induced crystallization is well studied in these areas, previous findings may not apply directly to the field of printed electronics where the molecular structures (i.e., rigid π-conjugated backbone decorated with flexible side chains) and the intermolecular interactions (i.e., π-π interactions, quadrupole interactions) of OSCs differ substantially from those of pharmaceuticals or flexible-chain polymers. Another critical difference is the important role of solvent evaporation in open systems, which defines the flow characteristics and determines the crystallization kinetics and pathways. In other words, flow-induced crystallization is intimately coupled with the mass transport processes driven by solvent evaporation during printing. In this Account, we will highlight these distinctions of flow-directed crystallization for printed electronics. In the context of solution printing of OSCs, the key issue that flow-directed crystallization addresses is the kinetics mismatch between crystallization and various transport processes during printing. We show that engineering fluid flows can tune the kinetics of OSC crystallization by expediting the nucleation and crystal growth processes, significantly enhancing thin film morphology and device performance. For small molecule semiconductors, nucleation can be enhanced and patterned by directing the evaporative flux via contact line engineering, and defective crystal growth can be alleviated by enhancing mass transport to yield significantly improved coherence length and reduced grain boundaries. For conjugated polymers, extensional and shear flow can expedite nucleation through flow-induced conformation change, facilitating the control of microphase separation, degree of crystallinity, domain alignment, and percolation. Although the nascent concept of flow-directed solution printing has not yet been widely adopted in the field of printed electronics, we anticipate that it can serve as a platform technology in the near future for improving device performance and for systematically tuning thin film morphology to construct structure-property relationships. From a fundamental perspective, it is imperative to develop a better understanding of the effects of fluid flow and mass transport on OSC crystallization as these processes are ubiquitous across all solution processing techniques and can critically impact charge transport properties.

The effects of ecology and evolutionary history on robust capuchin morphological diversity.

PubMed

Wright, Kristin A; Wright, Barth W; Ford, Susan M; Fragaszy, Dorothy; Izar, Patricia; Norconk, Marilyn; Masterson, Thomas; Hobbs, David G; Alfaro, Michael E; Lynch Alfaro, Jessica W

2015-01-01

Recent molecular work has confirmed the long-standing morphological hypothesis that capuchins are comprised of two distinct clades, the gracile (untufted) capuchins (genus Cebus, Erxleben, 1777) and the robust (tufted) capuchins (genus Sapajus Kerr, 1792). In the past, the robust group was treated as a single, undifferentiated and cosmopolitan species, with data from all populations lumped together in morphological and ecological studies, obscuring morphological differences that might exist across this radiation. Genetic evidence suggests that the modern radiation of robust capuchins began diversifying ∼2.5 Ma, with significant subsequent geographic expansion into new habitat types. In this study we use a morphological sample of gracile and robust capuchin craniofacial and postcranial characters to examine how ecology and evolutionary history have contributed to morphological diversity within the robust capuchins. We predicted that if ecology is driving robust capuchin variation, three distinct robust morphotypes would be identified: (1) the Atlantic Forest species (Sapajus xanthosternos, S. robustus, and S. nigritus), (2) the Amazonian rainforest species (S. apella, S. cay and S. macrocephalus), and (3) the Cerrado-Caatinga species (S. libidinosus). Alternatively, if diversification time between species pairs predicts degree of morphological difference, we predicted that the recently diverged S. apella, S. macrocephalus, S. libidinosus, and S. cay would be morphologically comparable, with greater variation among the more ancient lineages of S. nigritus, S. xanthosternos, and S. robustus. Our analyses suggest that S. libidinosus has the most derived craniofacial and postcranial features, indicative of inhabiting a more terrestrial niche that includes a dependence on tool use for the extraction of imbedded foods. We also suggest that the cranial robusticity of S. macrocephalus and S. apella are indicative of recent competition with sympatric gracile capuchin species, resulting in character displacement. Copyright © 2014 Elsevier Inc. All rights reserved.

Comparative descriptions of non-adult stages of four genera of Gordiids (Phylum: Nematomorpha).

PubMed

Szmygiel, Cleo; Schmidt-Rhaesa, Andreas; Hanelt, Ben; Bolek, Matthew G

2014-02-25

Freshwater hairworms infect terrestrial arthropods as larvae but are free-living in aquatic habitats as adults. Estimates suggest that only 18% of hairworm species have been described globally and biodiversity studies on this group have been hindered by unreliable ways of collecting adult free living worms over large geographical areas. However, recent work indicates that non-adult cyst stages of hairworms may be the most commonly encountered stages of gordiids in the environment, and can be used for discovering the hidden diversity of this group. Unfortunately, little information is available on the morphological characteristics of non-adult stages of hairworms. To address this problem, we describe and compare morphological characteristics of non-adult stages for nine species of African and North American gordiids from four genera (Chordodes, Gordius, Paragordius, and Neochordodes). Observations were made on the oviposition behavior of adult worms and morphological characteristics were recorded for egg strings, larvae and cysts using light and differential interference contrast microscopy and/or scanning electron microscopy. Our study indicates that three distinct types of oviposition behaviors and three distinct morphological types of egg string, larva, and cysts were present among the four genera of gordiids. Although species identification based on cyst characteristics was not always possible among different species of gordiids, cyst morphology was conserved among some genera and all clades of gordiids. More importantly, our work indicates that gordiid larval morphology can be used for predicting cyst morphology among other gordiid genera. The capability to identify and predict gordiid genera and/or clades based on cyst morphology will be useful for culturing gordiids in the laboratory from field collected cysts and these new techniques will undoubtedly allow others to discover new species of gordiids from around the world.

Distinct subspecies or phenotypic plasticity? Genetic and morphological differentiation of mountain honey bees in East Africa.

PubMed

Gruber, Karl; Schöning, Caspar; Otte, Marianne; Kinuthia, Wanja; Hasselmann, Martin

2013-09-01

Identifying the forces shaping intraspecific phenotypic and genotypic divergence are of key importance in evolutionary biology. Phenotypic divergence may result from local adaptation or, especially in species with strong gene flow, from pronounced phenotypic plasticity. Here, we examine morphological and genetic divergence among populations of the western honey bee Apis mellifera in the topographically heterogeneous East African region. The currently accepted "mountain refugia hypothesis" states that populations living in disjunct montane forests belong to a different lineage than those in savanna habitats surrounding these forests. We obtained microsatellite data, mitochondrial sequences, and morphometric data from worker honey bees collected from feral colonies in three montane forests and corresponding neighboring savanna regions in Kenya. Honey bee colonies from montane forests showed distinct worker morphology compared with colonies in savanna areas. Mitochondrial sequence data did not support the existence of the two currently accepted subspecies. Furthermore, analyses of the microsatellite data with a Bayesian clustering method did not support the existence of two source populations as it would be expected under the mountain refugia scenario. Our findings suggest that phenotypic plasticity rather than distinct ancestry is the leading cause behind the phenotypic divergence observed between montane forest and savanna honey bees. Our study thus corroborates the idea that high gene flow may select for increased plasticity.

Velcro-Like System Used to Fix a Protective Faecal Shield on Weevil Larvae.

PubMed

Skuhrovec, Jiří; Stejskal, Robert; Trnka, Filip; di Giulio, Andrea

2017-01-01

The last instar larva and pupa of Eucoeliodes mirabilis (A. Villa & G. B. Villa, 1835) (Curculionidae: Ceutorhynchini) are described using drawings and SEM images and are compared and keyed with already described larvae of 58 other ceutorhynchinae taxa. The larval body has an effective combination of morphological adaptations that assist a unique biological defensive strategy. All larval stages of E. mirabilis feed ectophytically on leaves of Euonymus europaeus L. (Celastraceae), and the larval body is covered with a thick faecal shield. The fixation of this protective shield on the larval back is performed by a peculiar dorsal microsculpture composed of a dense carpet of microtrichia on the thorax and abdomen, which serves effectively as a velcro system. Because of this strategy, macrosetae on the larval and pupal body of E. mirabilis are completely reduced. Larvae of E. mirabilis also have distinct morphological adaptations for protecting the spiracles against intrusion of faeces and avoiding occlusion of the tracheal system: a) microtrichia around spiracles are slightly shorter, distinctly stronger and are arranged with high-density and in clusters and b) spiracles are protected by an external safety valve. This strategy of E. mirabilis larvae is unique, although somewhat similar to that of Criocerinae and Blepharida-group leave beetles (Galerucinae) (both Coleoptera: Chrysomelidae), but with distinctly different morphological adaptations.

Velcro-Like System Used to Fix a Protective Faecal Shield on Weevil Larvae

PubMed Central

Stejskal, Robert; Trnka, Filip; di Giulio, Andrea

2017-01-01

The last instar larva and pupa of Eucoeliodes mirabilis (A. Villa & G. B. Villa, 1835) (Curculionidae: Ceutorhynchini) are described using drawings and SEM images and are compared and keyed with already described larvae of 58 other ceutorhynchinae taxa. The larval body has an effective combination of morphological adaptations that assist a unique biological defensive strategy. All larval stages of E. mirabilis feed ectophytically on leaves of Euonymus europaeus L. (Celastraceae), and the larval body is covered with a thick faecal shield. The fixation of this protective shield on the larval back is performed by a peculiar dorsal microsculpture composed of a dense carpet of microtrichia on the thorax and abdomen, which serves effectively as a velcro system. Because of this strategy, macrosetae on the larval and pupal body of E. mirabilis are completely reduced. Larvae of E. mirabilis also have distinct morphological adaptations for protecting the spiracles against intrusion of faeces and avoiding occlusion of the tracheal system: a) microtrichia around spiracles are slightly shorter, distinctly stronger and are arranged with high-density and in clusters and b) spiracles are protected by an external safety valve. This strategy of E. mirabilis larvae is unique, although somewhat similar to that of Criocerinae and Blepharida-group leave beetles (Galerucinae) (both Coleoptera: Chrysomelidae), but with distinctly different morphological adaptations. PMID:28125664

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruvindy, Rendy; White III, Richard Allen; Neilan, Brett Anthony

Modern microbial mats are potential analogues of some of Earth’s earliest ecosystems. Excellent examples can be found in Shark Bay, Australia, with mats of various morphologies. To further our understanding of the functional genetic potential of these complex microbial ecosystems, we conducted for the first time shotgun metagenomic analyses. We assembled metagenomic nextgeneration sequencing data to classify the taxonomic and metabolic potential across diverse morphologies of marine mats in Shark Bay. The microbial community across taxonomic classifications using protein-coding and small subunit rRNA genes directly extracted from the metagenomes suggests that three phyla Proteobacteria, Cyanobacteria and Bacteriodetes dominate all marinemore » mats. However, the microbial community structure between Shark Bay and Highbourne Cay (Bahamas) marine systems appears to be distinct from each other. The metabolic potential (based on SEED subsystem classifications) of the Shark Bay and Highbourne Cay microbial communities were also distinct. Shark Bay metagenomes have a metabolic pathway profile consisting of both heterotrophic and photosynthetic pathways, whereas Highbourne Cay appears to be dominated almost exclusively by photosynthetic pathways. Alternative non-rubisco-based carbon metabolism including reductive TCA cycle and 3-hydroxypropionate/4-hydroxybutyrate pathways is highly represented in Shark Bay metagenomes while not represented in Highbourne Cay microbial mats or any other mat forming ecosystems investigated to date. Potentially novel aspects of nitrogen cycling were also observed, as well as putative heavy metal cycling (arsenic, mercury, copper and cadmium). Finally, archaea are highly represented in Shark Bay and may have critical roles in overall ecosystem function in these modern microbial mats.« less

Morphology and identification of fly eggs: application in forensic entomology.

PubMed

Sanit, S; Sribanditmongkol, P; Sukontason, K L; Moophayak, K; Klong-Klaew, T; Yasanga, T; Sukontason, K

2013-06-01

Fly eggs found in corpses can be used as entomological evidence in forensic investigation. This study aims to investigate the morphology of forensically important fly eggs. Eggs of Chrysomya rufifacies, Chrysomya megacephala, Chrysomya pinguis, Chrysomya nigripes, Hypopygiopsis tumrasvini, Lucilia cuprina, Lucilia porphyrina and Musca domestica were examined using 1% potassium permanganate solution for 1 min. Morphometric analysis revealed that the mean length of Hy. tumrasvini (1.63 mm) and C. pinguis (1.65 mm) eggs was the longest, followed by that of L. porphyrina (1.45 mm), C. rufifacies (1.34 mm). The egg length, width of median area and darkness staining of hatching pleats were distinctive features. Four categories of median area were proposed, based on width; (1) distinctly wide (Megaselia scalaris, Synthesiomyia nudiseta); (2) wide (C. nigripes, M. domestica); (3) slightly widening (Hy. tumrasvini, L. cuprina, L. porphyrina); and (4) narrow (C. rufifacies, C. albiceps, C. megacephala, C. pinguis). Four species were examined using SEM, i.e., C. megacephala, C. pinguis, Hy. tumrasvini and L. porphyrina. The eggs of C. megacephala demonstrated swollen hatching pleats. Inside, the hexagon of the chorion appeared as a sponging bumpy feature. The egg of C. pinguis was similar to C. megacephala, except for the sponging bumpy feature on the outer surface of the hatching pleats. Regarding Hy. tumrasvini and L. porphyrina, their island structure was apparent at the inner surface of the upright hatching pleats. The key for identifying these eggs together with other reported species in Thailand has been updated.

Hydrothermal route to VO2 (B) nanorods: controlled synthesis and characterization

NASA Astrophysics Data System (ADS)

Song, Shaokun; Huang, Qiwei; Zhu, Wanting

2017-10-01

One-dimensional vanadium dioxides have attracted intensive attention owing to their distinctive structure and novel applications in catalysis, high energy lithium-ion batteries, chemical sensors/actuators and electrochemical devices etc. In this paper, large-scale VO2 (B) nanorods have been successfully synthesized via a versatile and environment friendly hydrothermal strategy using V2O5 as vanadium source and carbohydrates/alcohols as reductant. The obtained samples are characterized by XRD, FT-IR, TEM, and XPS techniques to investigate the effects of chemical parameters such as reductants, temperature, and time of synthesis on the structure and morphology of products. Results show that pure B phase VO2 with homogeneous nanorod-like morphology can be prepared easily at 180 °C for 3 days with glycerol as reluctant. Typically, the nanorod-like products are 0.5-1 μm long and 50 nm width. Furthermore, it is also confirmed that the products are consisted of VO2, corresponding to the B phase. More importantly, this novel approach is efficient, free of any harmful solvents and surfactants. Therefore, this efficient, green, and cost-saving route will have great potential in the large-scale fabrication of 1D VO2 (B) nanorods from the economic and environmental point of view.

A detailed view of microparticle formation by in-process monitoring of the glass transition temperature.

PubMed

Vay, Kerstin; Frieß, Wolfgang; Scheler, Stefan

2012-06-01

Biodegradable poly(D,L-lactide-co-glycolide) microspheres were prepared by a well-controlled emulsion solvent extraction/evaporation process. The objective of this study was to investigate how drug release can be modified by changing the morphology of the polymer matrix. The matrix structure was controlled by the preparation temperature which was varied between 10 and 35 °C, thus changing the 4 weeks release pattern from almost linear kinetics to a sigmoidal profile with a distinct lag phase and furthermore decreasing the encapsulation efficiency. By monitoring the glass transition temperature during the extraction process, it was shown that the preparation temperature determines the particle morphology by influencing the time span in which the polymer chains were mobile and flexible during the extraction process. Further factors determining drug release were found to be the molecular weight of the polymer and the rate of solvent removal. The latter, however, has also influence on the encapsulation efficiency with slow removal causing a higher drug loss. A secondary modification of the outer particle structure could be achieved by ethanolic post-treatment of the particles, which caused an extension of the lag phase and subsequently an accelerated drug release. Copyright © 2012. Published by Elsevier B.V.

Geographic variation in morphology of Alaska-breeding Bar-tailed Godwits (Limosa lapponica) is not maintained on their nonbreeding grounds in New Zealand

USGS Publications Warehouse

Conklin, Jesse R.; Battley, Phil F.; Potter, Murray A.; Ruthrauff, Daniel R.

2011-01-01

Among scolopacid shorebirds, Bar-tailed Godwits (Limosa lapponica) have unusually high intra- and intersexual differences in size and breeding plumage. Despite historical evidence for population structure among Alaska-breeding Bar-tailed Godwits (L. l. baueri), no thorough analysis, or comparison with the population's nonbreeding distribution, has been undertaken. We used live captures, field photography, museum specimens, and individuals tracked from New Zealand to describe geographic variation in size and plumage within the Alaska breeding range. We found a north-south cline in body size in Alaska, in which the smallest individuals of each sex occurred at the highest latitudes. Extent of male breeding plumage (proportion of nonbreeding contour feathers replaced) also increased with latitude, but female breeding plumage was most extensive at mid-latitudes. This population structure was not maintained in the nonbreeding season: morphometrics of captured birds and timing of migratory departures indicated that individuals from a wide range of breeding latitudes occur in each region and site in New Zealand. Links among morphology, phenology, and breeding location suggest the possibility of distinct Alaska breeding populations that mix freely in the nonbreeding season, and also imply that the strongest selection for size occurs in the breeding season.

Formation of aggregated nanoparticle spheres through femtosecond laser surface processing

NASA Astrophysics Data System (ADS)

Tsubaki, Alfred T.; Koten, Mark A.; Lucis, Michael J.; Zuhlke, Craig; Ianno, Natale; Shield, Jeffrey E.; Alexander, Dennis R.

2017-10-01

A detailed structural and chemical analysis of a class of self-organized surface structures, termed aggregated nanoparticle spheres (AN-spheres), created using femtosecond laser surface processing (FLSP) on silicon, silicon carbide, and aluminum is reported in this paper. AN-spheres are spherical microstructures that are 20-100 μm in diameter and are composed entirely of nanoparticles produced during femtosecond laser ablation of material. AN-spheres have an onion-like layered morphology resulting from the build-up of nanoparticle layers over multiple passes of the laser beam. The material properties and chemical composition of the AN-spheres are presented in this paper based on scanning electron microscopy (SEM), focused ion beam (FIB) milling, transmission electron microscopy (TEM), and energy dispersive x-ray spectroscopy (EDX) analysis. There is a distinct difference in the density of nanoparticles between concentric rings of the onion-like morphology of the AN-sphere. Layers of high-density form when the laser sinters nanoparticles together and low-density layers form when nanoparticles redeposit while the laser ablates areas surrounding the AN-sphere. The dynamic nature of femtosecond laser ablation creates a variety of nanoparticles that make-up the AN-spheres including Si/C core-shell, nanoparticles that directly fragmented from the base material, nanoparticles with carbon shells that retarded oxidation, and amorphous, fully oxidized nanoparticles.

Grammatical categories in the brain: the role of morphological structure.

PubMed

Longe, O; Randall, B; Stamatakis, E A; Tyler, L K

2007-08-01

The current study addresses the controversial issue of how different grammatical categories are neurally processed. Several lesion-deficit studies suggest that distinct neural substrates underlie the representation of nouns and verbs, with verb deficits associated with damage to left inferior frontal gyrus (LIFG) and noun deficits with damage to left temporal cortex. However, this view is not universally shared by neuropsychological and neuroimaging studies. We have suggested that these inconsistencies may reflect interactions between the morphological structure of nouns and verbs and the processing implications of this, rather than differences in their neural representations (Tyler et al. 2004). We tested this hypothesis using event-related functional magnetic resonance imaging, to scan subjects performing a valence judgment on unambiguous nouns and verbs, presented as stems ('snail, hear') and inflected forms ('snails, hears'). We predicted that activations for noun and verb stems would not differ, whereas inflected verbs would generate more activation in left frontotemporal areas than inflected nouns. Our findings supported this hypothesis, with greater activation of this network for inflected verbs compared with inflected nouns. These results support the claim that form class is not a first-order organizing principle underlying the representation of words but rather interacts with the processes that operate over lexical representations.

Which morphological characteristics are most influenced by the host matrix in downy mildews? A case study in Pseudoperonospora cubensis.

PubMed

Runge, Fabian; Ndambi, Beninweck; Thines, Marco

2012-01-01

Before the advent of molecular phylogenetics, species concepts in the downy mildews, an economically important group of obligate biotrophic oomycete pathogens, have mostly been based upon host range and morphology. While molecular phylogenetic studies have confirmed a narrow host range for many downy mildew species, others, like Pseudoperonospora cubensis affect even different genera. Although often morphological differences were found for new, phylogenetically distinct species, uncertainty prevails regarding their host ranges, especially regarding related plants that have been reported as downy mildew hosts, but were not included in the phylogenetic studies. In these cases, the basis for deciding if the divergence in some morphological characters can be deemed sufficient for designation as separate species is uncertain, as observed morphological divergence could be due to different host matrices colonised. The broad host range of P. cubensis (ca. 60 host species) renders this pathogen an ideal model organism for the investigation of morphological variations in relation to the host matrix and to evaluate which characteristics are best indicators for conspecificity or distinctiveness. On the basis of twelve morphological characterisitcs and a set of twelve cucurbits from five different Cucurbitaceae tribes, including the two species, Cyclanthera pedata and Thladiantha dubia, hitherto not reported as hosts of P. cubensis, a significant influence of the host matrix on pathogen morphology was found. Given the high intraspecific variation of some characteristics, also their plasticity has to be taken into account. The implications for morphological species determination and the confidence limits of morphological characteristics are discussed. For species delimitations in Pseudoperonospora it is shown that the ratio of the height of the first ramification to the sporangiophore length, ratio of the longer to the shorter ultimate branchlet, and especially the length and width of sporangia, as well as, with some reservations, their ratio, are the most suitable characteristics for species delimitation.

Which Morphological Characteristics Are Most Influenced by the Host Matrix in Downy Mildews? A Case Study in Pseudoperonospora cubensis

PubMed Central

Runge, Fabian; Ndambi, Beninweck; Thines, Marco

2012-01-01

Before the advent of molecular phylogenetics, species concepts in the downy mildews, an economically important group of obligate biotrophic oomycete pathogens, have mostly been based upon host range and morphology. While molecular phylogenetic studies have confirmed a narrow host range for many downy mildew species, others, like Pseudoperonospora cubensis affect even different genera. Although often morphological differences were found for new, phylogenetically distinct species, uncertainty prevails regarding their host ranges, especially regarding related plants that have been reported as downy mildew hosts, but were not included in the phylogenetic studies. In these cases, the basis for deciding if the divergence in some morphological characters can be deemed sufficient for designation as separate species is uncertain, as observed morphological divergence could be due to different host matrices colonised. The broad host range of P. cubensis (ca. 60 host species) renders this pathogen an ideal model organism for the investigation of morphological variations in relation to the host matrix and to evaluate which characteristics are best indicators for conspecificity or distinctiveness. On the basis of twelve morphological characterisitcs and a set of twelve cucurbits from five different Cucurbitaceae tribes, including the two species, Cyclanthera pedata and Thladiantha dubia, hitherto not reported as hosts of P. cubensis, a significant influence of the host matrix on pathogen morphology was found. Given the high intraspecific variation of some characteristics, also their plasticity has to be taken into account. The implications for morphological species determination and the confidence limits of morphological characteristics are discussed. For species delimitations in Pseudoperonospora it is shown that the ratio of the height of the first ramification to the sporangiophore length, ratio of the longer to the shorter ultimate branchlet, and especially the length and width of sporangia, as well as, with some reservations, their ratio, are the most suitable characteristics for species delimitation. PMID:23166582

Adaptive Traits Are Maintained on Steep Selective Gradients despite Gene Flow and Hybridization in the Intertidal Zone

PubMed Central

Canovas, Fernando; Ferreira Costa, Joana; Serrão, Ester A.; Pearson, Gareth A.

2011-01-01

Gene flow among hybridizing species with incomplete reproductive barriers blurs species boundaries, while selection under heterogeneous local ecological conditions or along strong gradients may counteract this tendency. Congeneric, externally-fertilizing fucoid brown algae occur as distinct morphotypes along intertidal exposure gradients despite gene flow. Combining analyses of genetic and phenotypic traits, we investigate the potential for physiological resilience to emersion stressors to act as an isolating mechanism in the face of gene flow. Along vertical exposure gradients in the intertidal zone of Northern Portugal and Northwest France, the mid-low shore species Fucus vesiculosus, the upper shore species Fucus spiralis, and an intermediate distinctive morphotype of F. spiralis var. platycarpus were morphologically characterized. Two diagnostic microsatellite loci recovered 3 genetic clusters consistent with prior morphological assignment. Phylogenetic analysis based on single nucleotide polymorphisms in 14 protein coding regions unambiguously resolved 3 clades; sympatric F. vesiculosus, F. spiralis, and the allopatric (in southern Iberia) population of F. spiralis var. platycarpus. In contrast, the sympatric F. spiralis var. platycarpus (from Northern Portugal) was distributed across the 3 clades, strongly suggesting hybridization/introgression with both other entities. Common garden experiments showed that physiological resilience following exposure to desiccation/heat stress differed significantly between the 3 sympatric genetic taxa; consistent with their respective vertical distribution on steep environmental clines in exposure time. Phylogenetic analyses indicate that F. spiralis var. platycarpus is a distinct entity in allopatry, but that extensive gene flow occurs with both higher and lower shore species in sympatry. Experimental results suggest that strong selection on physiological traits across steep intertidal exposure gradients acts to maintain the 3 distinct genetic and morphological taxa within their preferred vertical distribution ranges. On the strength of distributional, genetic, physiological and morphological differences, we propose elevation of F. spiralis var. platycarpus from variety to species level, as F. guiryi. PMID:21695117

Impact of the morphology and reactivity of nanoscale zero-valent iron (NZVI) on dechlorinating bacteria.

PubMed

Rónavári, Andrea; Balázs, Margit; Tolmacsov, Péter; Molnár, Csaba; Kiss, István; Kukovecz, Ákos; Kónya, Zoltán

2016-05-15

Nanoscale zero-valent iron (NZVI) is increasingly used for reducing chlorinated organic contaminants in soil or groundwater. However, little is known about what impact the particles will have on the biochemical processes and the indigenous microbial communities. Nanoiron reactivity is affected by the structure and morphology of nanoparticles that complicates the applicability in bioremediation. In this study, the effect of precursors (ferrous sulfate and ferric chloride) and reducing agents (sodium dithionite and sodium borohydride) on the morphology and the reactivity of NZVIs was investigated. We also studied the impact of differently synthesized NZVIs on microbial community, which take part in reductive dechlorination. We demonstrated that both the applied iron precursor and the reducing agent had influence on the structure of the nanoparticles. Spherical nanoparticles with higher Fe(0) content (>90%) was observed by using sodium borohydride as reducing agent, while application of sodium dithionite as reducing agent resulted nanostructures with lower Fe(0) content (between 68,7 and 85,5%). To determine the influence of differently synthesized NZVIs on cell viability anaerobic enriched microcosm were used. NVZI was used in 0.1 g/L concentration in all batch experiments. Relative amount of Dehalococcoides, sulfate reducers (SRBs) and methanogens were measured by quantitative PCR. We found that the relative amount of Dehalococcoides slowly decreased in all experiments independently from the precursor and reducing agent, whereas the total amount of microbes increased. The only clear distinction was in relative amount of sulfate reducers which were higher in the presence of NZVIs synthesized from sodium dithionite. Copyright © 2016 Elsevier Ltd. All rights reserved.

Out of Africa: modern human origins special feature: middle and later Pleistocene hominins in Africa and Southwest Asia.

PubMed

Rightmire, G Philip

2009-09-22

Approximately 700,000 years ago, Homo erectus in Africa was giving way to populations with larger brains accompanied by structural adjustments to the vault, cranial base, and face. Such early Middle Pleistocene hominins were not anatomically modern. Their skulls display strong supraorbital tori above projecting faces, flattened frontals, and less parietal expansion than is the case for Homo sapiens. Postcranial remains seem also to have archaic features. Subsequently, some groups evolved advanced skeletal morphology, and by ca. 200,000 years ago, individuals more similar to recent humans are present in the African record. These fossils are associated with Middle Stone Age lithic assemblages and, in some cases, Acheulean tools. Crania from Herto in Ethiopia carry defleshing cutmarks and superficial scoring that may be indicative of mortuary practices. Despite these signs of behavioral innovation, neither the Herto hominins, nor others from Late Pleistocene sites such as Klasies River in southern Africa and Skhūl/Qafzeh in Israel, can be matched in living populations. Skulls are quite robust, and it is only after approximately 35,000 years ago that people with more gracile, fully modern morphology make their appearance. Not surprisingly, many questions concerning this evolutionary history have been raised. Attention has centered on systematics of the mid-Pleistocene hominins, their paleobiology, and the timing of dispersals that spread H. sapiens out of Africa and across the Old World. In this report, I discuss structural changes characterizing the skulls from different time periods, possible regional differences in morphology, and the bearing of this evidence on recognizing distinct species.

Resolving Electrode Morphology’s Impact on Platinum Group Metal-Free Cathode Performance Using Nano-CT of 3D Hierarchical Pore and Ionomer Distribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komini Babu, Siddharth; Chung, Hoon T.; Zelenay, Piotr

This paper reports on the characterization of polymer electrolyte fuel cell (PEFC) cathodes featuring a platinum group metal-free (PGM-free) catalyst using nano-scale resolution X-ray computed tomography (nano-CT) and morphological analysis. PGM-free PEFC cathodes have gained significant interest in the past decade since they have the potential to dramatically reduce PEFC costs by eliminating the large platinum (Pt) raw material cost. However, several challenges remain before they are commercially viable. Since these catalysts have lower volumetric activity, the PGM-free cathodes are thicker and are subject to increased gas and proton transport resistances that reduce the performance. To better understand the efficacymore » of the catalyst and improve electrode performance, a detailed understanding the correlation between electrode fabrication, morphology, and performance is crucial. In this work, the pore/solid structure and the ionomer distribution was resolved in three dimensions (3D) using nano-CT for three PGM-free electrodes of varying Nafion® loading. The associated transport properties were evaluated from pore/particlescale simulations within the nano-CT imaged structure. These characterizations are then used to elucidate the microstructural origins of the dramatic changes in fuel cell performance with varying Nafion® ionomer loading. We show that this is primarily a result of distinct changes in ionomer’s spatial distribution. The significant impact of electrode morphology on performance highlights the importance of PGM-free electrode development in concert with efforts to improve catalyst activity and durability.« less

Resolving Electrode Morphology’s Impact on Platinum Group Metal-Free Cathode Performance Using Nano-CT of 3D Hierarchical Pore and Ionomer Distribution

DOE PAGES

Komini Babu, Siddharth; Chung, Hoon T.; Zelenay, Piotr; ...

2016-11-02

This paper reports on the characterization of polymer electrolyte fuel cell (PEFC) cathodes featuring a platinum group metal-free (PGM-free) catalyst using nano-scale resolution X-ray computed tomography (nano-CT) and morphological analysis. PGM-free PEFC cathodes have gained significant interest in the past decade since they have the potential to dramatically reduce PEFC costs by eliminating the large platinum (Pt) raw material cost. However, several challenges remain before they are commercially viable. Since these catalysts have lower volumetric activity, the PGM-free cathodes are thicker and are subject to increased gas and proton transport resistances that reduce the performance. To better understand the efficacymore » of the catalyst and improve electrode performance, a detailed understanding the correlation between electrode fabrication, morphology, and performance is crucial. In this work, the pore/solid structure and the ionomer distribution was resolved in three dimensions (3D) using nano-CT for three PGM-free electrodes of varying Nafion® loading. The associated transport properties were evaluated from pore/particlescale simulations within the nano-CT imaged structure. These characterizations are then used to elucidate the microstructural origins of the dramatic changes in fuel cell performance with varying Nafion® ionomer loading. We show that this is primarily a result of distinct changes in ionomer’s spatial distribution. The significant impact of electrode morphology on performance highlights the importance of PGM-free electrode development in concert with efforts to improve catalyst activity and durability.« less

Morphology and rheology in filamentous cultivations.

PubMed

Wucherpfennig, T; Kiep, K A; Driouch, H; Wittmann, C; Krull, R

2010-01-01

Because of their metabolic diversity, high production capacity, secretion efficiency, and capability of carrying out posttranslational modifications, filamentous fungi are widely exploited as efficient cell factories in the production of metabolites, bioactive substances, and native or heterologous proteins, respectively. There is, however, a complex relationship between the morphology of these microorganisms, transport phenomena, the viscosity of the cultivation broth, and related productivity. The morphological characteristics vary between freely dispersed mycelia and distinct pellets of aggregated biomass, every growth form having a distinct influence on broth rheology. Hence, the advantages and disadvantages for mycelial or pellet cultivation have to be balanced out carefully. Because of the still inadequate understanding of the morphogenesis of filamentous microorganisms, fungal morphology is often a bottleneck of productivity in industrial production. To obtain an optimized production process, it is of great importance to gain a better understanding of the molecular and cell biology of these microorganisms as well as the relevant approaches in biochemical engineering. In this chapter, morphology and growth of filamentous fungi are described, with special attention given to specific problems as they arise from fungal growth forms; growth and mass transfer in fungal biopellets are discussed as an example. To emphasize the importance of the flow behavior of filamentous cultivation broths, an introduction to rheology is also given, reviewing important rheological models and recent studies concerning rheological parameters. Furthermore, current knowledge on morphology and productivity in relation to the environom is outlined in the last section of this review. Copyright 2010 Elsevier Inc. All rights reserved.

The Architecture of Iron Microbial Mats Reflects the Adaptation of Chemolithotrophic Iron Oxidation in Freshwater and Marine Environments

PubMed Central

Chan, Clara S.; McAllister, Sean M.; Leavitt, Anna H.; Glazer, Brian T.; Krepski, Sean T.; Emerson, David

2016-01-01

Microbes form mats with architectures that promote efficient metabolism within a particular physicochemical environment, thus studying mat structure helps us understand ecophysiology. Despite much research on chemolithotrophic Fe-oxidizing bacteria, Fe mat architecture has not been visualized because these delicate structures are easily disrupted. There are striking similarities between the biominerals that comprise freshwater and marine Fe mats, made by Beta- and Zetaproteobacteria, respectively. If these biominerals are assembled into mat structures with similar functional morphology, this would suggest that mat architecture is adapted to serve roles specific to Fe oxidation. To evaluate this, we combined light, confocal, and scanning electron microscopy of intact Fe microbial mats with experiments on sheath formation in culture, in order to understand mat developmental history and subsequently evaluate the connection between Fe oxidation and mat morphology. We sampled a freshwater sheath mat from Maine and marine stalk and sheath mats from Loihi Seamount hydrothermal vents, Hawaii. Mat morphology correlated to niche: stalks formed in steeper O2 gradients while sheaths were associated with low to undetectable O2 gradients. Fe-biomineralized filaments, twisted stalks or hollow sheaths, formed the highly porous framework of each mat. The mat-formers are keystone species, with nascent marine stalk-rich mats comprised of novel and uncommon Zetaproteobacteria. For all mats, filaments were locally highly parallel with similar morphologies, indicating that cells were synchronously tracking a chemical or physical cue. In the freshwater mat, cells inhabited sheath ends at the growing edge of the mat. Correspondingly, time lapse culture imaging showed that sheaths are made like stalks, with cells rapidly leaving behind an Fe oxide filament. The distinctive architecture common to all observed Fe mats appears to serve specific functions related to chemolithotrophic Fe oxidation, including (1) removing Fe oxyhydroxide waste without entombing cells or clogging flow paths through the mat and (2) colonizing niches where Fe(II) and O2 overlap. This work improves our understanding of Fe mat developmental history and how mat morphology links to metabolism. We can use these results to interpret biogenicity, metabolism, and paleoenvironmental conditions of Fe microfossil mats, which would give us insight into Earth's Fe and O2 history. PMID:27313567

Cognition and Lobar Morphology in Full Mutation Boys with Fragile X Syndrome

ERIC Educational Resources Information Center

Meguid, Nagwa A.; Fahim, Cherine; Sami, Rasha; Nashaat, Neveen H.; Yoon, Uicheul; Anwar, Mona; El-Dessouky, Hosam M.; Shahine, Elham A.; Ibrahim, Ahmed Samir; Mancini-Marie, Adham; Evans, Alan C.

2012-01-01

The aims of the present study are twofold: (1) to examine cortical morphology (CM) associated with alterations in cognition in fragile X syndrome (FXS); (2) to characterize the CM profile of FXS versus FXS with an autism diagnosis (FXS+Aut) as a preliminary attempt to further elucidate the behavioral distinctions between the two sub-groups. We…

Sprouty / FGF signaling regulates the proximal-distal feather morphology and the size of dermal papillae

PubMed Central

Yue, Zhicao; Jiang, Ting Xin; Wu, Ping; Widelitz, Randall B; Chuong, Cheng Ming

2013-01-01

In a feather, there are distinct morphologies along the proximal-distal axis. The proximal part is a cylindrical stalk (calamus), whereas the distal part has barb and barbule branches. Here we focus on what molecular signaling activity can modulate feather stem cells to generate these distinct morphologies. We demonstrate the drastic tissue remodeling during feather cycling which includes initiation, growth and resting phases. In the growth phase, epithelial components undergo progressive changes from the collar growth zone to the ramogenic zone, to maturing barb branches along the proximal- distal axis. Mesenchymal components also undergo progressive changes from the dermal papilla, to the collar mesenchyme, to the pulp along the proximal- distal axis. Over-expression of Spry4, a negative regulator of receptor tyrosine kinases, promotes barb branch formation at the expense of the epidermal collar. It even induces barb branches from the follicle sheath (equivalent to the outer root sheath in hair follicles). The results are feathers with expanded feather vane regions and small or missing proximal feather shafts (the calamus). Spry4 also expands the pulp region while reducing the size of dermal papillae, leading to a failure to regenerate. In contrast, over-expressing Fgf10 increases the size of the dermal papillae, expands collar epithelia and mesenchyme, but also prevents feather branch formation and feather keratin differentiation. These results suggest that coordinated Sprouty/FGF pathway activity at different stages is important to modulate feather epidermal stem cells to form distinct feather morphologies along the proximal-distal feather axis. PMID:23000358

The influence of an innovative locomotor strategy on the phenotypic diversification of triggerfish (family: Balistidae).

PubMed

Dornburg, Alex; Sidlauskas, Brian; Santini, Francesco; Sorenson, Laurie; Near, Thomas J; Alfaro, Michael E

2011-07-01

Innovations in locomotor morphology have been invoked as important drivers of vertebrate diversification, although the influence of novel locomotion strategies on marine fish diversification remains largely unexplored. Using triggerfish as a case study, we determine whether the evolution of the distinctive synchronization of enlarged dorsal and anal fins that triggerfish use to swim may have catalyzed the ecological diversification of the group. By adopting a comparative phylogenetic approach to quantify median fin and body shape integration and to assess the tempo of functional and morphological evolution in locomotor traits, we find that: (1) functional and morphological components of the locomotive system exhibit a strong signal of correlated evolution; (2) triggerfish partitioned locomotor morphological and functional spaces early in their history; and (3) there is no strong evidence that a pulse of lineage diversification accompanied the major episode of phenotypic diversification. Together these findings suggest that the acquisition of a distinctive mode of locomotion drove an early radiation of shape and function in triggerfish, but not an early radiation of species. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Phytochemical constituents and chemosystematic significance of Chrozophora tinctoria (L.) Raf.

PubMed

Marzouk, Mona M; Hussein, Sameh R; Kassem, Mona E S; Kawashty, Salwa A; El Negoumy, Sabry I M

2016-07-01

Twelve compounds were isolated from Chrozophora tinctoria (L.) Raf. They were identified as kaempferol, kaempferol 3-O-β-glucopyranoside, kaempferol 3-O-(6″-α-rhamnopyranosyl)-β-glucopyranoside, quercetin, quercetin 3-O-β-glucopyranoside, quercetin 3-O-(6″-α-rhamnopyranosyl)-β-glucopyranoside, apigenin, apigenin 7-O-β-glucopyranoside, acacetin, gallic acid, methyl gallate and β-sitosterol-3-O-β-glucopyranoside. Their structures were elucidated by chemical and spectral methods. Furthermore, chemosystematics of the isolated compounds is briefly discussed. It was indicated that C. tinctoria is the only species of Chrozophora that has the capability to synthesis kaempferol aglycone and their glycosides, and the finding is supported by its distinct morphological and anatomical aspects.

Anatomy and histology of the male reproductive tract and spermatogenesis fine structure in the lesser anteater (Tamandua tetradactyla, Myrmecophagidae, Xenarthra): morphological evidences of reproductive functions.

PubMed

Rossi, L F; Luaces, J P; Aldana Marcos, H J; Cetica, P D; Perez Jimeno, G; Merani, M S

2013-08-01

The anatomy and histology of the male genital tract of the lesser anteater were studied. Fine details of spermatozoa regarding their genesis and morphology were also studied in six adult specimens. The testes lie in the pelvic cavity. The deferent duct emerges from the epididymis and opens into the ejaculatory duct, which drains into the membranous urethra. Accessory glands (prostate, seminal vesicle and bulbourethral gland) are histologically similar to those described in other mammals. The short penis presents an urethral orifice, while the corpus spongiosum becomes thinner at the end indicating the absence of a histologically defined glans. The seminiferous epithelium shows: (1) Sertoli cells with deep nuclear indentations, (2) spermatogonia with crusty-like chromatin, (3) spermatocytes at different stages of maturation and (4) three morphologically distinct stages of spermatid differentiation according to nuclear shape, acrosome development and chromatin condensation. Sperm heads appear oval. The length of the spermatozoa averages 67.33 ± 1.60 μm. Two specimens with inactive spermatogenesis were azoospermic. Their testes and epididymis presented sizes smaller than those with active spermatogenesis. These studies together with others in anteaters may contribute to successful breeding in conservation programmes. © 2012 Blackwell Verlag GmbH.

Deletion of Lipoteichoic Acid Synthase Impacts Expression of Genes Encoding Cell Surface Proteins in Lactobacillus acidophilus

PubMed Central

Selle, Kurt; Goh, Yong J.; Johnson, Brant R.; O’Flaherty, Sarah; Andersen, Joakim M.; Barrangou, Rodolphe; Klaenhammer, Todd R.

2017-01-01

Lactobacillus acidophilus NCFM is a well-characterized probiotic microorganism, supported by a decade of genomic and functional phenotypic investigations. L. acidophilus deficient in lipoteichoic acid (LTA), a major immunostimulant in Gram-positive bacteria, has been shown to shift immune system responses in animal disease models. However, the pleiotropic effects of removing LTA from the cell surface in lactobacilli are unknown. In this study, we surveyed the global transcriptional and extracellular protein profiles of two strains of L. acidophilus deficient in LTA. Twenty-four differentially expressed genes specific to the LTA-deficient strains were identified, including a predicted heavy metal resistance operon and several putative peptidoglycan hydrolases. Cell morphology and manganese sensitivity phenotypes were assessed in relation to the putative functions of differentially expressed genes. LTA-deficient L. acidophilus exhibited elongated cellular morphology and their growth was severely inhibited by elevated manganese concentrations. Exoproteomic surveys revealed distinct changes in the composition and relative abundances of several extracellular proteins and showed a bias of intracellular proteins in LTA-deficient strains of L. acidophilus. Taken together, these results elucidate the impact of ltaS deletion on the transcriptome and extracellular proteins of L. acidophilus, suggesting roles of LTA in cell morphology and ion homeostasis as a structural component of the Gram positive cell wall. PMID:28443071

Deletion of Lipoteichoic Acid Synthase Impacts Expression of Genes Encoding Cell Surface Proteins in Lactobacillus acidophilus.

PubMed

Selle, Kurt; Goh, Yong J; Johnson, Brant R; O'Flaherty, Sarah; Andersen, Joakim M; Barrangou, Rodolphe; Klaenhammer, Todd R

2017-01-01

Lactobacillus acidophilus NCFM is a well-characterized probiotic microorganism, supported by a decade of genomic and functional phenotypic investigations. L. acidophilus deficient in lipoteichoic acid (LTA), a major immunostimulant in Gram-positive bacteria, has been shown to shift immune system responses in animal disease models. However, the pleiotropic effects of removing LTA from the cell surface in lactobacilli are unknown. In this study, we surveyed the global transcriptional and extracellular protein profiles of two strains of L. acidophilus deficient in LTA. Twenty-four differentially expressed genes specific to the LTA-deficient strains were identified, including a predicted heavy metal resistance operon and several putative peptidoglycan hydrolases. Cell morphology and manganese sensitivity phenotypes were assessed in relation to the putative functions of differentially expressed genes. LTA-deficient L. acidophilus exhibited elongated cellular morphology and their growth was severely inhibited by elevated manganese concentrations. Exoproteomic surveys revealed distinct changes in the composition and relative abundances of several extracellular proteins and showed a bias of intracellular proteins in LTA-deficient strains of L. acidophilus . Taken together, these results elucidate the impact of ltaS deletion on the transcriptome and extracellular proteins of L. acidophilus , suggesting roles of LTA in cell morphology and ion homeostasis as a structural component of the Gram positive cell wall.

Morphological and molecular diversity and phylogenetic relationships among anuran trypanosomes from the Amazonia, Atlantic Forest and Pantanal biomes in Brazil.

PubMed

Ferreira, R C; Campaner, M; Viola, L B; Takata, C S A; Takeda, G F; Teixeira, M M G

2007-10-01

We examined for the presence of trypanosomes in blood samples from 259 anurans (47 species from 8 families), the majority of which were from the Brazilian Amazonia, Atlantic Forest and Pantanal biomes. Trypanosomes were detected by a combination of microhaematocrit and haemoculture methods in 45% of the anurans, and 87 cultures were obtained: 44 from Hylidae, 22 from Leptodactylidae, 15 from Bufonidae, 5 from Leiuperidae and 1 from an unidentified anuran. High morphological diversity (11 morphotypes) was observed among blood trypanosomes from anurans of different species and of the same species as well as among trypanosomes from the same individual. Conversely, morphologically similar trypanosomes were found in anurans from distinct species and biomes. ITS and SSU rDNA polymorphisms revealed high diversity among the 82 isolates examined. Twenty-nine genotypes could be distinguished, the majority distributed in 11 groups. Phylogenetic relationships based on rDNA sequences indicated that isolates from more phylogenetically related anurans are more closely related. Comparison of anuran trypanosomes from Brazil and other countries revealed several new species among the isolates examined in this study. Phylogenetic relationships suggest that host restriction, host switching and overall ecogeographical structure may have played a role in the evolution of the anuran trypanosomes.

Molecular and morphological approaches in discrimination of endangered Probarbus jullieni of Malaysia and Thailand stocks.

PubMed

Bhassu, S; Abd Rashid, Z

2009-09-01

The population structure of Probarbus jullieni from Malaysia and Thailand stocks was based on seven microsatellite primers and truss network measurements. Truss morphometric measurements were made on Temoleh, Probarbus jullieni to demonstrate the degree of speciation that can be induced by both biotic and abiotic conditions and contribute to the definition of different stocks of Probarbus sp. At the momment no relevant information on stock definition has been produced recently concerning Probarbus spp., which is now in IUCN threatened red list. We also summarize the possible discriminant morphological characteristics that shows differentiation between Malaysia and Thailand stocks. We also compare the levels of morphology and genetic differences for Malaysian stocks throughout one year of sampling to determine whether sampling season and possible sexual dimorphism can be detected in this fishes. A total of 25 different alleles were found across the two populations by the seven microsatellites, of which 21 and 19 alleles were detected in Pahang, Malaysia and Thailand, respectively At the population level, the mean number of alleles of Pahang (3.4991) per locus was higher than that (3.1665) of Thailand. From both molecular and morphometric measurements showed that there were two distinct populations. However the differences between these two populations showed that they belong to the same species with least degree of separation

Non-apoptotic cell death in animal development.

PubMed

Kutscher, Lena M; Shaham, Shai

2017-08-01

Programmed cell death (PCD) is an important process in the development of multicellular organisms. Apoptosis, a form of PCD characterized morphologically by chromatin condensation, membrane blebbing, and cytoplasm compaction, and molecularly by the activation of caspase proteases, has been extensively investigated. Studies in Caenorhabditis elegans, Drosophila, mice, and the developing chick have revealed, however, that developmental PCD also occurs through other mechanisms, morphologically and molecularly distinct from apoptosis. Some non-apoptotic PCD pathways, including those regulating germ cell death in Drosophila, still appear to employ caspases. However, another prominent cell death program, linker cell-type death (LCD), is morphologically conserved, and independent of the key genes that drive apoptosis, functioning, at least in part, through the ubiquitin proteasome system. These non-apoptotic processes may serve as backup programs when caspases are inactivated or unavailable, or, more likely, as freestanding cell culling programs. Non-apoptotic PCD has been documented extensively in the developing nervous system, and during the formation of germline and somatic gonadal structures, suggesting that preservation of these mechanisms is likely under strong selective pressure. Here, we discuss our current understanding of non-apoptotic PCD in animal development, and explore possible roles for LCD and other non-apoptotic developmental pathways in vertebrates. We raise the possibility that during vertebrate development, apoptosis may not be the major PCD mechanism.

When decisions on homologous structures cause ambiguous taxa relationships: the Neomorphinae (Aves, Cuculidae) example.

PubMed

Posso, S R; Donatelli, R J

2010-02-01

The anatomy of Neomorphinae is poorly understood and the systematics of this sub-family is also the most controversial of the cuckoo taxa, mainly with regard to the systematic position of Tapera and Dromococcyx. In this study, morphological similarities of the Neomorphinae are discussed after a comprehensive description of the cranial osteology was conducted in seven species, embracing all the Neomorphinae genera. This description is followed by comparisons with other cuckoos in order to contribute to the anatomy and systematics of this sub-family. In this way, we provide illustrations that enable the osteological descriptions and the proposed primary homologies to be visualised and compared. Even though Neomorphinae species share many cranial osteological characteristics, there are some anatomical divergences that allowed us to divide them into two distinct groups: (Dromococcyx/Tapera) and (Morococcyx(Neomorphus/Geococcyx)). After comparisons among all cuckoos this study suggests that Neomorphinae are more similar to Crotophaginae and Couinae than to other sub-families of cuckoos. Our results contrast with a recent phylogenetic study based on morphological features, mainly because alternative interpretations to the primary osteological homologies in this study grouped Tapera and Dromococcyx with Cuculinae. Although morphological studies can be used in phylogenetic analysis, we demonstrated here that decisions in the interpretation of the homologies can provide ambiguous results.

Interrelated structures of the transport shock and collisional relaxation layer in a multitemperature, multilevel ionized gas

NASA Technical Reports Server (NTRS)

Vinolo, A. R.; Clarke, J. H.

1973-01-01

The gas dynamic structures of the transport shock and the downstream collisional relaxation layer are evaluated for partially ionized monatomic gases. Elastic and inelastic collisional nonequilibrium effects are taken into consideration. In the microscopic model of the atom, three electronic levels are accounted for. By using an asymptotic technique, the shock morphology is found on a continuum flow basis. This procedure gives two distinct layers in which the nonequilibrium effects to be considered are different. A transport shock appears as the inner solution to an outer collisional relaxation layer. The results show four main interesting points: (1) on structuring the transport shock, ionization and excitation rates must be included in the formulation, since the flow is not frozen with respect to the population of the different electronic levels; (2) an electron temperature precursor appears at the beginning of the transport shock; (3) the collisional layer is rationally reduced to quadrature for special initial conditions, which (4) are obtained from new Rankine-Hugoniot relations for the inner shock.

Bacterial Sigma Factors and Anti-Sigma Factors: Structure, Function and Distribution

PubMed Central

Paget, Mark S.

2015-01-01

Sigma factors are multi-domain subunits of bacterial RNA polymerase (RNAP) that play critical roles in transcription initiation, including the recognition and opening of promoters as well as the initial steps in RNA synthesis. This review focuses on the structure and function of the major sigma-70 class that includes the housekeeping sigma factor (Group 1) that directs the bulk of transcription during active growth, and structurally-related alternative sigma factors (Groups 2–4) that control a wide variety of adaptive responses such as morphological development and the management of stress. A recurring theme in sigma factor control is their sequestration by anti-sigma factors that occlude their RNAP-binding determinants. Sigma factors are then released through a wide variety of mechanisms, often involving branched signal transduction pathways that allow the integration of distinct signals. Three major strategies for sigma release are discussed: regulated proteolysis, partner-switching, and direct sensing by the anti-sigma factor. PMID:26131973

Three Small-Receptive-Field Ganglion Cells in the Mouse Retina Are Distinctly Tuned to Size, Speed, and Object Motion

PubMed Central

Jacoby, Jason

2017-01-01

Retinal ganglion cells (RGCs) are frequently divided into functional types by their ability to extract and relay specific features from a visual scene, such as the capacity to discern local or global motion, direction of motion, stimulus orientation, contrast or uniformity, or the presence of large or small objects. Here we introduce three previously uncharacterized, nondirection-selective ON–OFF RGC types that represent a distinct set of feature detectors in the mouse retina. The three high-definition (HD) RGCs possess small receptive-field centers and strong surround suppression. They respond selectively to objects of specific sizes, speeds, and types of motion. We present comprehensive morphological characterization of the HD RGCs and physiological recordings of their light responses, receptive-field size and structure, and synaptic mechanisms of surround suppression. We also explore the similarities and differences between the HD RGCs and a well characterized RGC with a comparably small receptive field, the local edge detector, in response to moving objects and textures. We model populations of each RGC type to study how they differ in their performance tracking a moving object. These results, besides introducing three new RGC types that together constitute a substantial fraction of mouse RGCs, provide insights into the role of different circuits in shaping RGC receptive fields and establish a foundation for continued study of the mechanisms of surround suppression and the neural basis of motion detection. SIGNIFICANCE STATEMENT The output cells of the retina, retinal ganglion cells (RGCs), are a diverse group of ∼40 distinct neuron types that are often assigned “feature detection” profiles based on the specific aspects of the visual scene to which they respond. Here we describe, for the first time, morphological and physiological characterization of three new RGC types in the mouse retina, substantially augmenting our understanding of feature selectivity. Experiments and modeling show that while these three “high-definition” RGCs share certain receptive-field properties, they also have distinct tuning to the size, speed, and type of motion on the retina, enabling them to occupy different niches in stimulus space. PMID:28100743

Numerical Simulations of Silverpit Crater Collapse

NASA Technical Reports Server (NTRS)

Collins, G. S.; Ivanov, B. A.; Turtle, E. P.; Melosh, H. J.

2003-01-01

The Silverpit crater is a recently discovered, 60-65 Myr old complex crater, which lies buried beneath the North Sea, about 150 km east of Britain. High-resolution images of Silverpit's subsurface structure, provided by three-dimensional seismic reflection data, reveal an inner-crater morphology similar to that expected for a 5-8 km diameter terrestrial crater. The crater walls show evidence of terrace-style slumping and there is a distinct central uplift, which may have produced a central peak in the pristine crater morphology. However, Silverpit is not a typical 5-km diameter terrestrial crater, because it exhibits multiple, concentric rings outside the main cavity. External concentric rings are normally associated with much larger impact structures, for example Chicxulub on Earth, or Orientale on the Moon. Furthermore, external rings associated with large impacts on the terrestrial planets and moons are widely-spaced, predominantly inwardly-facing, asymmetric scarps. However, the seismic data show that the external rings at Silverpit represent closely-spaced, concentric faultbound graben, with both inwardly and outwardly facing fault-scarps. This type of multi-ring structure directly analogous to the Valhalla-type multi-ring basins found on the icy satellites. Thus, the presence and style of the multiple rings at Silverpit is surprising given both the size of the crater and its planetary setting. A further curiosity of the Silverpit structure is that the external concentric rings appear to be extensional features on the West side of the crater and compressional features on the East side. The crater also lies in a local depression, thought to be created by postimpact movement of a salt layer buried beneath the crater.

NanoSIMS Sheds Light on the Origin and Significance of Early Archean Organic Microstructures from the Pilbara of Australia

NASA Technical Reports Server (NTRS)

Oehler, Dorothy Z.; Robert, Francois; Meibom, Anders; Mostefaoui, Smail; Selo, Madeleine; Walter, Malcolm, R.; Sugitani, Kenichiro; Allwood, Abigail; Gibson, Everett K.

2008-01-01

NanoSIMS was used to characterize sub-micron scale morphology and elemental composition (C, N, S, Si, O) of organic microstructures in Early Archean (3 - 3.4 Ga) charts from the Pilbara of Western Australia. Three categories of structures were analyzed: small spheroids in clusters; spindle-shaped remains; and large spheroids. All are relatively poorly preserved and occur within the chert matrix of the samples. Carbonaceous material in a secondary hydrothermal vein also was analyzed, as an example of non-indigenous organic matter. Comparisons were made of NanoSIMS characteristics of the Archean samples and those from well-preserved, biogenic microfossils in the 0.8 Ga Bitter Springs Formation. The comparisons show that the Pilbara microstructures are generally distinct from material in the hydrothermal vein but similar in morphology and elemental composition to the Bitter Springs microfossils. In addition, the Pilbara structures exhibit a spatial relationship to silicon and oxygen that seemingly reflects silica nucleation on organic surfaces; this argues that the organic frameworks of the Archean structures were present in the sediment during crystallization of the silica matrix. The structures are thus interpreted as being indigenous to the enclosing sediment. While these results are suggestive of Early Archean biogenicity and are consistent with a growing body of data suggesting that life on Earth was well established by 3 to 3.4 Ga, work is continuing to determine the N/C and 13C ratios of individual forms, and this should provide additional insight into the derivation and significance of these ancient organic remains.

Colombia a Source of Cacao Genetic Diversity As Revealed by the Population Structure Analysis of Germplasm Bank of Theobroma cacao L.

PubMed

Osorio-Guarín, Jaime A; Berdugo-Cely, Jhon; Coronado, Roberto Antonio; Zapata, Yeny Patricia; Quintero, Constanza; Gallego-Sánchez, Gerardo; Yockteng, Roxana

2017-01-01

Beans of the species Theobroma cacao L., also known as cacao, are the raw material to produce chocolate. Colombian cacao has been classified as a fine flavor cacao that represents the 5% of cacao world's production. Colombian genetic resources from this species are conserved in ex situ and in-field germplasm banks, since T. cacao has recalcitrant seeds to desication and long-term storage. Currently, the collection of T. cacao of the Colombian Corporation of Agricultural Research (CORPOICA) has approximately 700 germplasm accessions. We conducted a molecular analysis of Corpoica's cacao collection and a morphological characterization of some accessions with the goal to study its genetic diversity and population structure and, to select interesting accessions for the cacao's breeding program. Phenotypic evaluation was performed based on 18 morphological traits and 4 biochemical traits. PCA analysis of morphological traits explained 60.6% of the total variation in seven components and 100% of the total variation of biochemical traits in four components, grouping the collection in 4 clusters for both variables. We explored 565 accessions from Corpoica's germplasm and 252 accessions from reference populations using 96 single nucleotide polymorphism (SNP) molecular markers. Molecular patterns of cacao Corpoica's collection were obtained amplifying specific alleles in a Fluidigm platform that used integrated circuits of fluids. Corpoica's collection showed highest genetic diversity [Expected Heterozygosity ( H E = 0.314), Observed Heterozygosity ( H O = 0.353)] that is reduced when reference populations were included in the dataset ( H E = 0.294, H O = 0.261). The collection was divided into four clusters based on population structure analysis. Cacao accessions from distinct groups showed some taxonomic concordance and reflected their geographic origins. For instance, accessions classified as Criollo were clearly differentiated in one group and we identified two new Colombian genetic groups. Using a number of allelic variations based on 87 SNP markers and 22 different morphological/biochemical traits, a core collection with a total of 232 accessions was selected as a primary genetic resource for cacao breeders.

Colombia a Source of Cacao Genetic Diversity As Revealed by the Population Structure Analysis of Germplasm Bank of Theobroma cacao L.

PubMed Central

Osorio-Guarín, Jaime A.; Berdugo-Cely, Jhon; Coronado, Roberto Antonio; Zapata, Yeny Patricia; Quintero, Constanza; Gallego-Sánchez, Gerardo; Yockteng, Roxana

2017-01-01

Beans of the species Theobroma cacao L., also known as cacao, are the raw material to produce chocolate. Colombian cacao has been classified as a fine flavor cacao that represents the 5% of cacao world’s production. Colombian genetic resources from this species are conserved in ex situ and in-field germplasm banks, since T. cacao has recalcitrant seeds to desication and long-term storage. Currently, the collection of T. cacao of the Colombian Corporation of Agricultural Research (CORPOICA) has approximately 700 germplasm accessions. We conducted a molecular analysis of Corpoica’s cacao collection and a morphological characterization of some accessions with the goal to study its genetic diversity and population structure and, to select interesting accessions for the cacao’s breeding program. Phenotypic evaluation was performed based on 18 morphological traits and 4 biochemical traits. PCA analysis of morphological traits explained 60.6% of the total variation in seven components and 100% of the total variation of biochemical traits in four components, grouping the collection in 4 clusters for both variables. We explored 565 accessions from Corpoica’s germplasm and 252 accessions from reference populations using 96 single nucleotide polymorphism (SNP) molecular markers. Molecular patterns of cacao Corpoica’s collection were obtained amplifying specific alleles in a Fluidigm platform that used integrated circuits of fluids. Corpoica’s collection showed highest genetic diversity [Expected Heterozygosity (HE = 0.314), Observed Heterozygosity (HO = 0.353)] that is reduced when reference populations were included in the dataset (HE = 0.294, HO = 0.261). The collection was divided into four clusters based on population structure analysis. Cacao accessions from distinct groups showed some taxonomic concordance and reflected their geographic origins. For instance, accessions classified as Criollo were clearly differentiated in one group and we identified two new Colombian genetic groups. Using a number of allelic variations based on 87 SNP markers and 22 different morphological/biochemical traits, a core collection with a total of 232 accessions was selected as a primary genetic resource for cacao breeders. PMID:29209353

Molecular characterization of natural orchid in South slopes of Mount Merapi, Sleman regency, Yogyakarta

NASA Astrophysics Data System (ADS)

Ferdiani, Defika I.; Devi, Fera L.; Koentjana, Johan P.; Milasari, Asri F.; Nur'aini, Indah; Semiarti, Endang

2015-09-01

Natural orchid is one of the most important tropical biodiversity. In Indonesia there are ± 6000 species out of 30000 orchids species in the world, of which there are ± 60 species at Mount Merapi. Repetitive eruption of Merapi have wiped out the biodiversity of orchids, therefore the efforts to conserve the orchids and to establish the database of natural orchids in Mount Merapi are needed. The orchid's database can be created based on DNA analysis, and establish barcoding DNA. DNA-barcodes can be used as molecular markers. The different character of morphology usually shows different pattern in DNA fragments. This research aims to characterize the phenotype and genotype of natural orchids of Mt. Merapi based on morphology and the structure of DNA in trnL-F intergenic region of chloroplasts DNA of orchid. Amplified Fragment Length Polymorphism (AFLP) technique was used to characterize the molecular types of orchids in silico of intergenic space area of orchid chloroplast. In this study, 11 species of orchids were characterized based on morphological and molecular characters. The molecular characters were obtained from trnL-F intergenic region of leaves chloroplasts. The data indicates that there is a conserve DNA pattern in all orchids and the distinctive characters of some orchids. In this study, based on trnL-F intergenic region of chloroplast genome, the phylogenetic tree revealed that 11 species of orchids at Mt. Merapi can be grouped into 2 clades, that matched with morphological characters.

Growth of elaborate microbial pinnacles in Lake Vanda, Antarctica.

PubMed

Sumner, D Y; Jungblut, A D; Hawes, I; Andersen, D T; Mackey, T J; Wall, K

2016-11-01

Microbial pinnacles in ice-covered Lake Vanda, McMurdo Dry Valleys, Antarctica, extend from the base of the ice to more than 50 m water depth. The distribution of microbial communities, their photosynthetic potential, and pinnacle morphology affects the local accumulation of biomass, which in turn shapes pinnacle morphology. This feedback, plus environmental stability, promotes the growth of elaborate microbial structures. In Lake Vanda, all mats sampled from greater than 10 m water depth contained pinnacles with a gradation in size from <1-mm-tall tufts to pinnacles that were centimeters tall. Small pinnacles were cuspate, whereas larger ones had variable morphology. The largest pinnacles were up to ~30 cm tall and had cylindrical bases and cuspate tops. Pinnacle biomass was dominated by cyanobacteria from the morphological and genomic groups Leptolyngbya, Phormidium, and Tychonema. The photosynthetic potential of these cyanobacterial communities was high to depths of several millimeters into the mat based on PAM fluorometry, and sufficient light for photosynthesis penetrated ~5 mm into pinnacles. The distribution of photosynthetic potential and its correlation to pinnacle morphology suggests a working model for pinnacle growth. First, small tufts initiate from random irregularities in prostrate mat. Some tufts grow into pinnacles over the course of ~3 years. As pinnacles increase in size and age, their interiors become colonized by a more diverse community of cyanobacteria with high photosynthetic potential. Biomass accumulation within this subsurface community causes pinnacles to swell, expanding laminae thickness and creating distinctive cylindrical bases and cuspate tops. This change in shape suggests that pinnacle morphology emerges from a specific distribution of biomass accumulation that depends on multiple microbial communities fixing carbon in different parts of pinnacles. Similarly, complex patterns of biomass accumulation may be reflected in the morphology of elaborate ancient stromatolites. © 2016 John Wiley & Sons Ltd.

Local versus Generalized Phenotypes in Two Sympatric Aurelia Species: Understanding Jellyfish Ecology Using Genetics and Morphometrics

PubMed Central

Chiaverano, Luciano M.; Bayha, Keith W.; Graham, William M.

2016-01-01

For individuals living in environmentally heterogeneous environments, a key component for adaptation and persistence is the extent of phenotypic differentiation in response to local environmental conditions. In order to determine the extent of environmentally induced morphological variation in a natural population distributed along environmental gradients, it is necessary to account for potential genetic differences contributing to morphological differentiation. In this study, we set out to quantify geographic morphological variation in the moon jellyfish Aurelia exposed at the extremes of a latitudinal environmental gradient in the Gulf of Mexico (GoM). We used morphological data based on 28 characters, and genetic data taken from mitochondrial cytochrome oxidase I (COI) and nuclear internal transcribed spacer 1 (ITS-1). Molecular analyses revealed the presence of two genetically distinct species of Aurelia co-occurring in the GoM: Aurelia sp. 9 and Aurelia c.f. sp. 2, named for its divergence from (for COI) and similarity to (for ITS-1) Aurelia sp. 2 (Brazil). Neither species exhibited significant population genetic structure between the Northern and the Southeastern Gulf of Mexico; however, they differed greatly in the degree of geographic morphological variation. The morphology of Aurelia sp. 9 exhibited ecophenotypic plasticity and varied significantly between locations, while morphology of Aurelia c.f. sp. 2 was geographically invariant (i.e., canalized). The plastic, generalist medusae of Aurelia sp. 9 are likely able to produce environmentally-induced, “optimal” phenotypes that confer high relative fitness in different environments. In contrast, the non-plastic generalist individuals of Aurelia c.f. sp. 2 likely produce environmentally-independent phenotypes that provide the highest fitness across environments. These findings suggest the two Aurelia lineages co-occurring in the GoM were likely exposed to different past environmental conditions (i.e., different selective pressures) and evolved different strategies to cope with environmental variation. This study highlights the importance of using genetics and morphometric data to understand jellyfish ecology, evolution and systematics. PMID:27332545

Local versus Generalized Phenotypes in Two Sympatric Aurelia Species: Understanding Jellyfish Ecology Using Genetics and Morphometrics.

PubMed

Chiaverano, Luciano M; Bayha, Keith W; Graham, William M

2016-01-01

For individuals living in environmentally heterogeneous environments, a key component for adaptation and persistence is the extent of phenotypic differentiation in response to local environmental conditions. In order to determine the extent of environmentally induced morphological variation in a natural population distributed along environmental gradients, it is necessary to account for potential genetic differences contributing to morphological differentiation. In this study, we set out to quantify geographic morphological variation in the moon jellyfish Aurelia exposed at the extremes of a latitudinal environmental gradient in the Gulf of Mexico (GoM). We used morphological data based on 28 characters, and genetic data taken from mitochondrial cytochrome oxidase I (COI) and nuclear internal transcribed spacer 1 (ITS-1). Molecular analyses revealed the presence of two genetically distinct species of Aurelia co-occurring in the GoM: Aurelia sp. 9 and Aurelia c.f. sp. 2, named for its divergence from (for COI) and similarity to (for ITS-1) Aurelia sp. 2 (Brazil). Neither species exhibited significant population genetic structure between the Northern and the Southeastern Gulf of Mexico; however, they differed greatly in the degree of geographic morphological variation. The morphology of Aurelia sp. 9 exhibited ecophenotypic plasticity and varied significantly between locations, while morphology of Aurelia c.f. sp. 2 was geographically invariant (i.e., canalized). The plastic, generalist medusae of Aurelia sp. 9 are likely able to produce environmentally-induced, "optimal" phenotypes that confer high relative fitness in different environments. In contrast, the non-plastic generalist individuals of Aurelia c.f. sp. 2 likely produce environmentally-independent phenotypes that provide the highest fitness across environments. These findings suggest the two Aurelia lineages co-occurring in the GoM were likely exposed to different past environmental conditions (i.e., different selective pressures) and evolved different strategies to cope with environmental variation. This study highlights the importance of using genetics and morphometric data to understand jellyfish ecology, evolution and systematics.

Nuclear markers reveal that inter-lake cichlids' similar morphologies do not reflect similar genealogy.

PubMed

Kassam, Daud; Seki, Shingo; Horic, Michio; Yamaoka, Kosaku

2006-08-01

The apparent inter-lake morphological similarity among East African Great Lakes' cichlid species/genera has left evolutionary biologists asking whether such similarity is due to sharing of common ancestor or mere convergent evolution. In order to answer such question, we first used Geometric Morphometrics, GM, to quantify morphological similarity and then subsequently used Amplified Fragment Length Polymorphism, AFLP, to determine if similar morphologies imply shared ancestry or convergent evolution. GM revealed that not all presumed morphological similar pairs were indeed similar, and the dendrogram generated from AFLP data indicated distinct clusters corresponding to each lake and not inter-lake morphological similar pairs. Such results imply that the morphological similarity is due to convergent evolution and not shared ancestry. The congruency of GM and AFLP generated dendrograms imply that GM is capable of picking up phylogenetic signal, and thus GM can be potential tool in phylogenetic systematics.

THE RADIO CONTINUUM STRUCTURE OF CENTAURUS A AT 1.4 GHz

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feain, I. J.; Cornwell, T. J.; Ekers, R. D.

2011-10-10

A 45 deg{sup 2} radio continuum imaging campaign of the nearest radio galaxy, Centaurus A, is reported. Using the Australia Telescope Compact Array and the Parkes 64 m radio telescope at 1.4 GHz, the spatial resolution of the resultant image is {approx}600 pc ({approx}50''), resolving the {approx}>500 kpc giant radio lobes with approximately five times better physical resolution compared to any previous image, and making this the most detailed radio continuum image of any radio galaxy to date. In this paper, we present these new data and discuss briefly some of the most interesting morphological features that we have discoveredmore » in the images. The two giant outer lobes are highly structured and considerably distinct. The southern part of the giant northern lobe naturally extends out from the northern middle lobe with uniformly north-streaming emission. The well known northern loop is resolved into a series of semi-regular shells with a spacing of approximately 25 kpc. The northern part of the giant northern lobe also contains identifiable filaments and partial ring structures. As seen in previous single-dish images at lower angular resolution, the giant southern lobe is not physically connected to the core at radio wavelengths. Almost the entirety of the giant southern lobe is resolved into a largely chaotic and mottled structure which appears considerably different (morphologically) to the diffuse regularity of the northern lobe. We report the discovery of a vertex and a vortex near the western boundary of the southern lobe, two striking, high surface brightness features that are named based on their morphology and not their dynamics (which are presently unknown). The vortex and vertex are modeled as reaccelerated lobe emission due to shocks from the active galactic nucleus itself or from the passage of a dwarf elliptical galaxy through the lobe. Preliminary polarimetric and spectral index studies support a plasma reacceleration model and could explain the origin of the Faraday rotation structure detected in the southern lobe. In addition, there are a series of low surface brightness wisps detected around the edges of both the giant lobes.« less

A critical approach to the definition of Darwinian units of selection.

PubMed

Rinkevich, B

2000-12-01

What are the biological units of selection? In fact, the notion of "unit of selection" (UOS) is blurred by ambiguity and controversy. To further evaluate the biological entities that are the objects of natural selection, three novel conceptual criteria (holism, minimalism, functionalism) are critically applied; they reveal, in addition to the self-evident case of the "individual," at least six distinct types of UOSs. These UOSs do not always have a defined structural organization; they can be parts of a living organism, a cohesive group of conspecifics, a multiunit entity, a totipotent cell, a DNA fragment, or a whole organism. UOS types diversify by amalgamation or parcelation processes of apparent entities. Therefore, previous attempts to characterize the UOSs solely on some morphological levels (gene, individual, group) without applying stringent criteria have failed to cope with the structural variations of natural phenomena and have led to the ambiguity of terms used.

The role of confined collagen geometry in decreasing nucleation energy barriers to intrafibrillar mineralization.

PubMed

Kim, Doyoon; Lee, Byeongdu; Thomopoulos, Stavros; Jun, Young-Shin

2018-03-06

Mineralization of collagen is critical for the mechanical functions of bones and teeth. Calcium phosphate nucleation in collagenous structures follows distinctly different patterns in highly confined gap regions (nanoscale confinement) than in less confined extrafibrillar spaces (microscale confinement). Although the mechanism(s) driving these differences are still largely unknown, differences in the free energy for nucleation may explain these two mineralization behaviors. Here, we report on experimentally obtained nucleation energy barriers to intra- and extrafibrillar mineralization, using in situ X-ray scattering observations and classical nucleation theory. Polyaspartic acid, an extrafibrillar nucleation inhibitor, increases interfacial energies between nuclei and mineralization fluids. In contrast, the confined gap spaces inside collagen fibrils lower the energy barrier by reducing the reactive surface area of nuclei, decreasing the surface energy penalty. The confined gap geometry, therefore, guides the two-dimensional morphology and structure of bioapatite and changes the nucleation pathway by reducing the total energy barrier.

Explicit topographic expressions of neotectonic movements along the Tønder Graben structure, Denmark - an example of fault reactivation due to deglaciation

NASA Astrophysics Data System (ADS)

Sandersen, Peter B. E.; Jørgensen, Flemming; Møller, Rasmus R.

2013-04-01

The topography in southern Denmark is dominated by Late Glacial outwash plains surrounding remnants of older Saalian hills. The outwash plains were formed outside the Last Glacial Maximum (LGM) with a gently sloping surface averaging 1 m per 1.000 m. Formed in a proglacial environment the outwash plains have largely remained undisturbed by glacier ice and we would thus expect any topographic irregularities to relate to postglacial events. In that sense, the outwash plains constitute an ideal landform for identifying tectonic events during the late and postglacial periods. Irregularities in the present day glacial topography, such as kettle holes and other types of depressions are commonly linked to decay of dead ice. But this perception needs in many instances a further examination especially because of the recent availability of highly detailed LiDAR data. The investigation area is situated above the Tønder Graben structure at the northern margin of the North German Basin. The Tønder Graben was formed along the WNW-ESE trending Rømø Fault Zone and mobilization of Zechstein salt added to the evolution of the graben. The Tønder Graben has caused a significant impact on the Mesozoic and Cenozoic sedimentary successions and is for instance clearly expressed as large elongate depressions in the Top Chalk surface. On the larger scale, no clear signs of the outline of the graben structure can be seen in the present day topography to indicate movements during the Quaternary. However, when high resolution LiDAR data is investigated carefully signatures of neotectonic movements emerges on the outwash plain. Among these are morphological features such as: 1) Significant level changes along distinct lineaments, 2) frequent slope changes of neighboring areas, 3) 180 degree changes in dip direction and 4) presence of close lying polygonal areas with marked shifts in terrain level. All these morphological features are found right on top of the Tønder Graben. In addition to these smaller scale morphological features we also identify a large area of the outwash plain without the expected slope forming a large and unusual threshold in the surface. Combined with information from boreholes and seismic data we relate the morphological irregularities to movements of the underlying Tønder Graben structure. Because we observe both negative and positive morphological features we propose that the tectonic movement within the graben has a strike-slip component. Based on dating of soil samples from depressions in the outwash plain the onset of the movements are constrained to around 9.000 years BP. We conclude that the deformation of the outwash plain is related to short-term reactivations of faults related to the Tønder Graben structure following the deglaciation.

Identifying the pollen of an extinct spruce species in the Late Quaternary sediments of the Tunica Hills region, south-eastern United States

USGS Publications Warehouse

Luke Mander,; Jacklyn Rodriguez,; Pietra G. Mueller,; Jackson, Stephen T.; Surangi W. Punyasena,

2014-01-01

Late Quaternary fluvial deposits in the Tunica Hills region of Louisiana and Mississippi are rich in spruce macrofossils of the extinct species Picea critchfieldii, the one recognized plant extinction of the Late Quaternary. However, the morphology of P. critchfieldii pollen is unknown, presenting a barrier to the interpretation of pollen spectra from the last glacial of North America. To address this issue, we undertook a morphometric study of Picea pollen from Tunica Hills. Morphometric data, together with qualitative observations of pollen morphology using Apotome fluorescence microscopy, indicate that Picea pollen from Tunica Hills is morphologically distinct from the pollen of P. glauca, P. mariana and P. rubens. Measurements of grain length, corpus width and corpus height indicate that Picea pollen from Tunica Hills is larger than the pollen of P. mariana and P. rubens, and is slightly larger than P. glauca pollen. We argue that the morphologically distinctive Tunica Hills Picea pollen was probably produced by the extinct spruce species P. critchfieldii. These morphological differences could be used to identify P. critchfieldii in existing and newly collected pollen records, which would refine its paleoecologic and biogeographic history and clarify the nature and timing of its extinction in the Late Quaternary.