scholarly journals A new Devonian euthycarcinoid reveals the use of different respiratory strategies during the marine-to-terrestrial transition in the myriapod lineage

2020 ◽  
Vol 7 (10) ◽  
pp. 201037
Author(s):  
Pierre Gueriau ◽  
James C. Lamsdell ◽  
Roy A. Wogelius ◽  
Phillip L. Manning ◽  
Victoria M. Egerton ◽  
...  
Keyword(s):  
Terrestrial Ecosystems ◽  
Terrestrial Environment ◽  
Tracheal System ◽  
Air Breathing ◽  
X Ray ◽  
Land Colonization ◽  
Spherical Cavities ◽  
Additional Support ◽  
Available Information ◽  
Extinct Group

Myriapods were, together with arachnids, the earliest animals to occupy terrestrial ecosystems, by at least the Silurian. The origin of myriapods and their land colonization have long remained puzzling until euthycarcinoids, an extinct group of aquatic arthropods considered amphibious, were shown to be stem-group myriapods, extending the lineage to the Cambrian and evidencing a marine-to-terrestrial transition. Although possible respiratory structures comparable to the air-breathing tracheal system of myriapods are visible in several euthycarcinoids, little is known about the mechanism by which they respired. Here, we describe a new euthycarcinoid from Upper Devonian alluvio-lagoonal deposits of Belgium. Synchrotron-based elemental X-ray analyses were used to extract all available information from the only known specimen. Sulfur X-ray fluorescence (XRF) mapping and spectroscopy unveil sulfate evaporation stains, spread over the entire slab, suggestive of a very shallow-water to the terrestrial environment prior to burial consistent with an amphibious lifestyle. Trace metal XRF mapping reveals a pair of ventral spherical cavities or chambers on the second post-abdominal segment that do not compare to any known feature in aquatic arthropods, but might well play a part in air-breathing. Our data provide additional support for amphibious lifestyle in euthycarcinoids and show that different respiratory strategies were used during the marine-to-terrestrial transition in the myriapod lineage.

Eds Of Radioactive Particles By Self-Induced Fluorescence

1990 ◽  
Vol 48 (2) ◽  
pp. 238-239
Author(s):  
Gregory L. Finch ◽  
Richard G. Cuddihy
Keyword(s):  
Electron Beam Irradiation ◽  
Nuclear Reactor ◽  
X Rays ◽  
Reactor Accident ◽  
Internal Radiation ◽  
X Ray ◽  
External Sources ◽  
X Irradiation ◽  
Available Information ◽  
Individual Particles

The elemental composition of individual particles is commonly measured by using energydispersive spectroscopic microanalysis (EDS) of samples excited with electron beam irradiation. Similarly, several investigators have characterized particles by using external monochromatic X-irradiation rather than electrons. However, there is little available information describing measurements of particulate characteristic X rays produced not from external sources of radiation, but rather from internal radiation contained within the particle itself. Here, we describe the low-energy (< 20 KeV) characteristic X-ray spectra produced by internal radiation self-excitation of two general types of particulate samples; individual radioactive particles produced during the Chernobyl nuclear reactor accident and radioactive fused aluminosilicate particles (FAP). In addition, we compare these spectra with those generated by conventional EDS.Approximately thirty radioactive particle samples from the Chernobyl accident were on a sample of wood that was near the reactor when the accident occurred. Individual particles still on the wood were microdissected from the bulk matrix after bulk autoradiography.

Structure and activity of phosphoglycerate mutase

1981 ◽  
Vol 293 (1063) ◽  
pp. 121-130 ◽  
Keyword(s):  
Active Site ◽  
Transfer Reaction ◽  
Chemical Kinetic ◽  
Phosphoglycerate Mutase ◽  
Phosphoryl Transfer ◽  
X Ray ◽  
Histidine Residues ◽  
Ping Pong ◽  
Available Information ◽  
Structure And Activity

The structure of yeast phosphoglycerate mutase determined by X-ray crystallographic and amino acid sequence studies has been interpreted in terms of the chemical, kinetic and mechanistic observations made on this enzyme. There are two histidine residues at the active site, with imidazole groups almost parallel to each other and approximately 0.4 nm apart, positioned close to the 2 and 3 positions of the substrate. The simplest interpretation of the available information suggests that a ping-pong type mechanism operates in which at least one of these histidine residues participates in the phosphoryl transfer reaction. The flexible C-terminal region also plays an important role in the enzymic reaction.

scholarly journals Structural Modeling of Glutathiones Containing Selenium and Tellurium

2016 ◽  
Vol 8 (1) ◽  
pp. 102
Author(s):  
Valter A. Nascimento ◽  
Petr Melnikov ◽  
André V. D. Lanoa ◽  
Anderson F. Silva ◽  
Lourdes Z. Z. Consolo
Keyword(s):  
Molecular Mechanics ◽  
Structural Characteristics ◽  
Structural Modeling ◽  
Structural Description ◽  
Ionic Radii ◽  
X Ray ◽  
Bond Angles ◽  
Bond Lengths ◽  
Available Information ◽  
Related Compounds

<p>The comparative structural modeling of reduced and oxidized glutathiones, as well as their derivatives containing selenium and tellurium in chalcogen sites (Ch = Se, Te) has provided detailed information about the bond lengths and bond angles, filling the gap in the structural characteristics of these tri-peptides. The investigation using the molecular mechanics technique with good approximation confirmed the available information on X-ray refinements for the related compounds. It was shown that Ch-H and Ch-C bond lengths grow in parallel with the increasing chalcogen ionic radii. Although the distances C-C, C-O, and C-N are very similar, the geometry of GChChG glutathiones is rich in conformers owing to the possibility of rotation about the bridge Ch-Ch. It is confirmed that the distances Ch-Ch are essentially independent of substituents in most of chalcogen compounds from elemental chalcogens to oxydized glutathiones. The standard program Hyperchem 7.5 has proved to be an appropriate tool for the structural description of less-common bioactive compositions when direct X-ray data are missing.</p>

scholarly journals Hardness Ratio in Evolving Low-Mass X-ray Binary Systems

1987 ◽  
Vol 125 ◽  
pp. 199-199
Author(s):  
J. Shaham ◽  
M. Tavani
Keyword(s):  
Neutron Star ◽  
Accretion Disk ◽  
Binary Systems ◽  
Spectral Component ◽  
Soft Component ◽  
Hard Component ◽  
X Ray ◽  
Low Mass ◽  
Additional Support ◽  
X Ray Binaries

Spectral observations of low-mass X-ray binaries (LMXBs) show that the soft component usually dominates over the hard one. These results provide additional support to an interpretation based on models of LMXBs in which the neutron star while, on the average, spinning up, is also experiencing a spinning down torque. Under these conditions, a fraction of the luminosity associated with the gravitational release of energy on the surface of the accreting neutron star may manifest itself as luminosity originating in the inner part of the accretion disk. It is probably possible to separate the two contributions; the stellar luminosity can be associated with the hard component of the spectrum and the disk luminosity, related to the exchange of energy due to the torque between the rapidly spinning neutron star and the accretion disk, can be associated with the soft spectral component.

scholarly journals Interaction between molecular clouds and MeV–TeV cosmic-ray protons escaped from supernova remnants

2019 ◽  
Vol 71 (4) ◽  
Author(s):  
Ken Makino ◽  
Yutaka Fujita ◽  
Kumiko K Nobukawa ◽  
Hironori Matsumoto ◽  
Yutaka Ohira
Keyword(s):  
Gamma Rays ◽  
Molecular Clouds ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Iron Line ◽  
X Ray ◽  
Line Intensities ◽  
Neutral Gas ◽  
Additional Support

Abstract Recent discovery of the X-ray neutral iron line (Fe  i Kα at 6.40 keV) around several supernova remnants (SNRs) show that MeV cosmic-ray (CR) protons are distributed around the SNRs and are interacting with neutral gas there. We propose that these MeV CRs are the ones that have been accelerated at the SNRs together with GeV–TeV CRs. In our analytical model, the MeV CRs are still confined in the SNR when the SNR collides with molecular clouds. After the collision, the MeV CRs leak into the clouds and produce the neutral iron line emissions. On the other hand, GeV–TeV CRs had already escaped from the SNRs and emitted gamma-rays through interaction with molecular clouds surrounding the SNRs. We apply this model to the SNRs W 28 and W 44 and show that it can reproduce the observations of the iron line intensities and the gamma-ray spectra. This could be additional support of the hadronic scenario for the gamma-ray emissions from these SNRs.

The influence of experimentally induced changes in the (Mg + Ca):K balance on protein bodies formed in developing Cucurbita seeds

1994 ◽  
Vol 72 (3) ◽  
pp. 364-369 ◽  
Author(s):  
John N. A. Lott ◽  
Irene Ockenden ◽  
Patrice Kerr ◽  
Marcia West ◽  
Thelma Leech ◽  
...  
Keyword(s):  
Protein Bodies ◽  
Mineral Nutrient ◽  
Elemental Content ◽  
Crystal Formation ◽  
Nutrient Storage ◽  
X Ray ◽  
Dense Bodies ◽  
Transmission Electron ◽  
Additional Support ◽  
Induced Changes

Phytate, the main mineral nutrient storage compound in seeds, is stored inside protein bodies. Phytate is usually concentrated in dense bodies called globoid crystals. In 1985, Lott and co-workers proposed that the balance of (Mg + Ca):K may be important in controlling globoid crystal formation and provided some experimental evidence to support this proposal. To test this hypothesis further, developing Cucurbita fruits were injected with sterile K salt solutions. Squash cotyledons generally have large globoid crystals and a relatively high (Mg + Ca):K ratio. We hypothesized that experimental reduction of the ratio by the addition of K would result in the alteration of the size and number of globoid crystals. Developing seeds were remarkably resistant to attempts to alter the elements taken up for storage. The elemental content of embryo tissues was measured quantitatively with neutron activation analysis. Controls plus those few samples showing a distinct shift in the ratio owing to elevated K content were analyzed further. Energy dispersive X-ray analysis of cryogenically prepared samples was used to study the elemental content of globoid crystals and transmission electron microscopy was used to study the ultrastructure of the protein bodies. The results provide additional support for the hypothesis being tested. Key words: phytate, globoid crystals, Cucurbita, seeds, mineral nutrients, protein bodies.

scholarly journals Comparative Transcriptome Analysis During the Seven Developmental Stages of Channel Catfish (Ictalurus punctatus) and Tra Catfish (Pangasianodon hypophthalmus) Provides Novel Insights for Terrestrial Adaptation

2021 ◽  
Vol 11 ◽  
Author(s):  
Xiaoli Ma ◽  
Mei Shang ◽  
Baofeng Su ◽  
Anne Wiley ◽  
Max Bangs ◽  
...  
Keyword(s):  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Developmental Stages ◽  
Critical Time ◽  
Comparative Genomic ◽  
Swim Bladder ◽  
Terrestrial Environment ◽  
Air Breathing ◽  
Pangasianodon Hypophthalmus ◽  
Tra Catfish

Tra catfish (Pangasianodon hypophthalmus), also known as striped catfish, is a facultative air-breather that uses its swim bladder as an air-breathing organ (ABO). A related species in the same order (Siluriformes), channel catfish (Ictalurus punctatus), does not possess an ABO and thus cannot breathe in the air. Tra and channel catfish serve as great comparative models for investigating possible genetic underpinnings of aquatic to land transitions, as well as for understanding genes that are crucial for the development of the swim bladder and the function of air-breathing in tra catfish. In this study, hypoxia challenge and microtomy experiments collectively revealed critical time points for the development of the air-breathing function and swim bladder in tra catfish. Seven developmental stages in tra catfish were selected for RNA-seq analysis based on their transition to a stage that could live at 0 ppm oxygen. More than 587 million sequencing clean reads were generated, and a total of 21,448 unique genes were detected. A comparative genomic analysis between channel catfish and tra catfish revealed 76 genes that were present in tra catfish, but absent from channel catfish. In order to further narrow down the list of these candidate genes, gene expression analysis was performed for these tra catfish-specific genes. Fourteen genes were inferred to be important for air-breathing. Of these, HRG, GRP, and CX3CL1 were identified to be the most likely genes related to air-breathing ability in tra catfish. This study provides a foundational data resource for functional genomic studies in air-breathing function in tra catfish and sheds light on the adaptation of aquatic organisms to the terrestrial environment.

scholarly journals CATALOGUE OF AQUATIC MITES FROM THE MINHO RIVER (NW IBERIAN PENINSULA)

2021 ◽  
pp. 44-47
Author(s):  
Harold Cantallo ◽  
Nuno Gomes ◽  
Carlos Antunes ◽  
Tiago Ribeiro ◽  
Maria Inês Gomes ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
New Records ◽  
Taxonomic Diversity ◽  
Extensive Literature ◽  
Global Biodiversity Information Facility ◽  
Terrestrial Environment ◽  
History Museum ◽  
Minho River ◽  
By Catch ◽  
Available Information

Acari are a subclass of chelicerate arthropods that includes mites and ticks. The present study focuses on the taxonomic diversity of aquatic mites in the Portuguese territory of the Minho Region. Our aim was to compile all available information and thus generate a list of species linking them to the site where they were recorded. Aquatic species were all those that live exclusively in the marine environment, deep sea, intertidal, freshwater, brackish water or in transitional environments with the terrestrial environment if their lifestyle is associated with the aquatic environment. Since the first records of Portuguese endemic mites by Lunblad in the 1950s several authors have contributed to accurately catalogue, record, and redescribe this vast group in Portugal and Minho consecutively. In our review in this work, we used the Global Biodiversity Information Facility (GBIF) to obtain previous occurrences supplemented by an extensive literature review and the book collection Süßwasserfauna von Mitteleuropa, among others. Additionally, we resorted to active sampling and by-catch sampling in the Portuguese section of the Rio Minho catchment area. The collected organisms represent 12 new records for the Minho River and among them 10 are new records for Portugal, which were deposited in the Natural History Museum of the Iberian Peninsula - NatMIP (“Museu de História Natural da Península Ibérica”), Vila Nova de Cerveira, Portugal.

scholarly journals Eight-year variations in atmospheric radiocesium in Fukushima City

2021 ◽  
Author(s):  
Akira Watanabe ◽  
Mizuo Kajino ◽  
Kazuhiko Ninomiya ◽  
Yoshitaka Nagahashi ◽  
Atsushi Shinohara
Keyword(s):  
Particle Size ◽  
Numerical Model ◽  
Causal Relationship ◽  
Seasonal Variations ◽  
Fluorescence Analysis ◽  
Terrestrial Ecosystems ◽  
Nuclear Accident ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
X Ray

Abstract. After the Fukushima nuclear accident, atmospheric 134Cs and 137Cs measurements were taken in Fukushima city for eight years, from March 2011 to March 2019. The surface air concentrations and deposition of radio-Cs were high in winter and low in summer; these trends are the opposite of those observed in a contaminated forest area. The half-lives of 137Cs in the concentrations and deposition before 2015 (275 d and 1.11 y) were significantly shorter than those after 2015 (756 d and 4.69 y). The dissolved fractions of precipitation were larger than the particulate fractions before 2015, but the particulate fractions were larger after 2016. The half-lives of 137Cs in the concentrations and deposition were shorter before 2015, probably because the dissolved radio-Cs was discharged from the local terrestrial ecosystems more rapidly than the particulate radio-Cs. X-ray fluorescence analysis suggested that biotite may have played a key role in the environmental behavior of particulate forms of radio-Cs after 2014. However, the causal relationship between the seasonal variations in particle size distributions and the possible sources of particles is not yet fully understood. The current study also proposes a method of evaluating the consistency of a numerical model for radio-Cs resuspension and suggests that improvements to the model are necessary.

scholarly journals Treatment of Unstable Injury of Pelvic Bones in Pregnant (Case Report)

2021 ◽  
pp. 80-83
Author(s):  
M.L. Holovakha ◽  
O.V. Bohdan ◽  
M.O. Kozhemiaka ◽  
V.I. Pertsov
Keyword(s):  
Surgical Intervention ◽  
Early Period ◽  
Pregnant Patient ◽  
Road Accident ◽  
X Ray ◽  
Pelvic Bones ◽  
Bilateral Fracture ◽  
Musculoskeletal Function ◽  
Additional Support ◽  
Boundary Fracture

Summary. There is no doubt in the relevance of the problem of treatment of patients with unstable fractures of pelvic bones, since these injuries involve a threat to the patient's life in the early period and often lead to disability in the future. This article presents a rare case of treatment of a patient with an unstable pelvis injury, while being 16 weeks pregnant. Patient A., born 1993, was admitted after a road accident injury. The examinations included: X-ray, CT, ultrasound, and gynecologist consultation. The patient was diagnosed with closed bilateral fracture of the pubic and ischial bones with displacement; rupture of the left sacroiliac joint with the boundary fracture of the sacrum (61-С1.3 by the Tile-AO-ASIF classification). The patient was 16 weeks pregnant. The surgery – open reduction and extramedullary metalosteosynthesis – was performed at the 9th day after the injury. The patient was discharged to outpatient treatment at the 12th day after the surgery. She started walking on crutches 3 weeks after the surgery; no additional support was needed since 1.5 months after the surgery. The patient gave birth at 39 weeks by surgical intervention (caesarean section). The baby's condition was assessed as 8 according to the Apgar scale. At the control examination 10 months after the surgery, musculoskeletal function of the patient was fully restored.

Sign in / Sign up

Export Citation Format

Share Document