scholarly journals Lanthanide-Dependent Methylotrophs of the Family Beijerinckiaceae: Physiological and Genomic Insights

2019 ◽  
Vol 86 (1) ◽  
Author(s):  
Carl-Eric Wegner ◽  
Linda Gorniak ◽  
Stefan Riedel ◽  
Martin Westermann ◽  
Kirsten Küsel
Keyword(s):  
Methanol Oxidation ◽  
Carbon Assimilation ◽  
Methylotrophic Bacteria ◽  
Alcohol Dehydrogenases ◽  
New Members ◽  
Physiological Diversity ◽  
Wide Range ◽  
Low Mass ◽  
Taxonomic Groups ◽  
Methylated Sulfur Compounds

ABSTRACT Methylotrophic bacteria use methanol and related C1 compounds as carbon and energy sources. Methanol dehydrogenases are essential for methanol oxidation, while lanthanides are important cofactors of many pyrroloquinoline quinone-dependent methanol dehydrogenases and related alcohol dehydrogenases. We describe here the physiological and genomic characterization of newly isolated Beijerinckiaceae bacteria that rely on lanthanides for methanol oxidation. A broad physiological diversity was indicated by the ability to metabolize a wide range of multicarbon substrates, including various sugars, and organic acids, as well as diverse C1 substrates such as methylated amines and methylated sulfur compounds. Methanol oxidation was possible only in the presence of low-mass lanthanides (La, Ce, and Nd) at submicromolar concentrations (>100 nM). In a comparison with other Beijerinckiaceae, genomic and transcriptomic analyses revealed the usage of a glutathione- and tetrahydrofolate-dependent pathway for formaldehyde oxidation and channeling methyl groups into the serine cycle for carbon assimilation. Besides a single xoxF gene, we identified two additional genes for lanthanide-dependent alcohol dehydrogenases, including one coding for an ExaF-type alcohol dehydrogenase, which was so far not known in Beijerinckiaceae. Homologs for most of the gene products of the recently postulated gene cluster linked to lanthanide utilization and transport could be detected, but for now it remains unanswered how lanthanides are sensed and taken up by our strains. Studying physiological responses to lanthanides under nonmethylotrophic conditions in these isolates as well as other organisms is necessary to gain a more complete understanding of lanthanide-dependent metabolism as a whole. IMPORTANCE We supplemented knowledge of the broad metabolic diversity of the Beijerinckiaceae by characterizing new members of this family that rely on lanthanides for methanol oxidation and that possess additional lanthanide-dependent enzymes. Considering that lanthanides are critical resources for many modern applications and that recovering them is expensive and puts a heavy burden on the environment, lanthanide-dependent metabolism in microorganisms is an exploding field of research. Further research into how isolated Beijerinckiaceae and other microbes utilize lanthanides is needed to increase our understanding of lanthanide-dependent metabolism. The diversity and widespread occurrence of lanthanide-dependent enzymes make it likely that lanthanide utilization varies in different taxonomic groups and is dependent on the habitat of the microbes.

scholarly journals Multi-stable composite twisting structure for morphing applications

2012 ◽  
Vol 468 (2141) ◽  
pp. 1230-1251 ◽  
Author(s):  
X. Lachenal ◽  
P. M. Weaver ◽  
S. Daynes
Keyword(s):  
Analytical Model ◽  
Material Properties ◽  
Degrees Of Freedom ◽  
Design Parameters ◽  
Engineering Structures ◽  
The Past ◽  
Wide Range ◽  
Morphing Structure ◽  
Low Mass ◽  
Unstable States

Conventional shape-changing engineering structures use discrete parts articulated around a number of linkages. Each part carries the loads, and the articulations provide the degrees of freedom of the system, leading to heavy and complex mechanisms. Consequently, there has been increased interest in morphing structures over the past decade owing to their potential to combine the conflicting requirements of strength, flexibility and low mass. This article presents a novel type of morphing structure capable of large deformations, simply consisting of two pre-stressed flanges joined to introduce two stable configurations. The bistability is analysed through a simple analytical model, predicting the positions of the stable and unstable states for different design parameters and material properties. Good correlation is found between experimental results, finite-element modelling and predictions from the analytical model for one particular example. A wide range of design parameters and material properties is also analytically investigated, yielding a remarkable structure with zero stiffness along the twisting axis.

Molecular detection and isolation from Antarctica of methylotrophic bacteria able to grow with methylated sulfur compounds

2005 ◽  
Vol 28 (6) ◽  
pp. 541-554 ◽  
Author(s):  
S. Azra Moosvi ◽  
Ian R. McDonald ◽  
David A. Pearce ◽  
Donovan P. Kelly ◽  
Ann P. Wood
Keyword(s):  
Molecular Detection ◽  
Sulfur Compounds ◽  
Methylotrophic Bacteria ◽  
Methylated Sulfur Compounds

Revision of Pycnandra subgenus Achradotypus (Sapotaceae), with five new species from New Caledonia

2010 ◽  
Vol 23 (3) ◽  
pp. 185 ◽  
Author(s):  
Ulf Swenson ◽  
Jérôme Munzinger
Keyword(s):  
New Caledonia ◽  
Iucn Red List ◽  
Red List ◽  
Corolla Lobe ◽  
Vegetation Types ◽  
New Members ◽  
Infrageneric Classification ◽  
Humid Forest ◽  
Leaf Venation ◽  
Wide Range

Pycnandra is a genus of Sapotaceae (Chrysophylloideae), restricted to New Caledonia, and includes ~60 species. The genus is a member of the monophyletic Niemeyera complex of Australia and New Caledonia and it is characterised by the lack of staminodes and a fruit containing a single seed, plano-convex cotyledons and absence of endosperm. In New Caledonia, several segregate genera have been recognised, but weak cladistic support for these groups and homoplasious morphology renders a narrow generic concept untenable. Instead, a broad generic circumscription of Pycnandra with an infrageneric classification recognising the subgenera Achradotypus, Leptostylis, Pycnandra, Sebertia and Trouettia results in a stable nomenclature. Here we revise Pycnandra subg. Achradotypus that includes 14 species, of which five (P. belepensis, P. blaffartii, P. bracteolata, P. glabella, and P. ouaiemensis) are described as new. Members of subg. Achradotypus are distinguished from other subgenera on the basis of a character combination of two stamens opposite each corolla lobe (except P. litseiflora), glabrous leaves (except P. belepensis and P. decandra), a distinctive reticulate tertiary leaf venation (except P. comptonii), and sepal-like bracts that often are borne along the pedicel. All species are restricted to Grande Terre except for P. decandra, whose distribution also extends to nearby Art Island (Belep Islands), and P. belepensis, which is endemic to that same island. The members grow in a wide range of vegetation types from dry maquis to humid forest, from sea level to the highest mountain massif, and on ultramafic soils to schist and greywacke (not limestone). Because of past and present threats such as mining, logging and fire, preliminary IUCN Red List assessments are provided for all species. Five taxa (P. chartacea, P. decandra subsp. decandra, P. glabella, P. litseiflora, and P. neocaledonica) are proposed the IUCN status Endangered, and P. belepensis and P. ouaiemensis are proposed to be Critically Endangered. We suggest that some locations where these species occur should be given protection in the form of nature reserves.

scholarly journals Resurrecting low-mass axion dark matter via a dynamical QCD scale

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Lucien Heurtier ◽  
Fei Huang ◽  
Tim M.P. Tait
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Temperature Dependent ◽  
Axion Field ◽  
Wide Range ◽  
The Standard Model ◽  
Low Mass ◽  
Higher Temperature ◽  
Relic Abundance ◽  
Dependent Mass

Abstract In the framework where the strong coupling is dynamical, the QCD sector may confine at a much higher temperature than it would in the Standard Model, and the temperature-dependent mass of the QCD axion evolves in a non-trivial way. We find that, depending on the evolution of ΛQCD, the axion field may undergo multiple distinct phases of damping and oscillation leading generically to a suppression of its relic abundance. Such a suppression could therefore open up a wide range of parameter space, resurrecting in particular axion dark-matter models with a large Peccei-Quinn scale fa ≫ 1012 GeV, i.e., with a lighter mass than the standard QCD axion.

The Dose Determines the Stimulation (and Poison): Development of A Chemical Hormesis Database

1997 ◽  
Vol 16 (6) ◽  
pp. 545-559 ◽  
Author(s):  
Edward J. Calabrese ◽  
Linda A. Baldwin
Keyword(s):  
A Priori ◽  
Dose Range ◽  
Evaluation Criteria ◽  
Metabolic Effects ◽  
Growth Responses ◽  
Wide Range ◽  
Order Of Magnitude ◽  
Real Phenomenon ◽  
Effect Level ◽  
Taxonomic Groups

A comprehensive effort was undertaken to identify articles demonstrating chemical hormesis. Nearly 4000 potentially relevant articles were retrieved from preliminary computer searches utilizing various keyword descriptors and extensive cross-referencing. A priori evaluation criteria were established including study design features (e.g., number of doses, dose range), statistical analysis, and reproducibility of results. Evidence of chemical hormesis was judged to have occurred in approximately 350 of the 4000 studies evaluated. Chemical hormesis was observed in a wide range of taxonomic groups and involved agents representing highly diverse chemical classes, many of potential environmental relevance. Numerous biologic endpoints were assessed, with growth responses the most prevalent, followed by metabolic effects, longevity, reproductive responses, and survival. Hormetic responses were generally observed to be of limited magnitude with the average low-dose maximum stimulation approximately 50% greater than controls. The hormetic dose-response range was generally limited to about one order of magnitude with the upper end of the hormetic curve approaching the estimated no-observed-effect level (NOEL) for the particular endpoint. Based on the evaluation criteria, high to moderate evidence of hormesis was observed in studies comprised of ≥ doses with <3 doses in the hormetic zone. The present analysis suggests that chem ical hormesis is a reproducible and generalizable biologic phenomenon. Over the last decade advances have been made providing mechanistic insight helpful in explaining the phenomenon of chemical hormesis in multiple biologic systems with various endpoints. The reason for the uncertainty surrounding the existence of hormesis as a “real phenomenon” is believed to be the result of its relatively infrequent observation in the literature due to experimental design considerations, especially with respect to the number of doses, range of doses, and endpoint selection.

scholarly journals Swift/XRT, Chandra, and XMM–Newton observations of IGR J17091–3624 as it returns into quiescence

2020 ◽  
Vol 497 (1) ◽  
pp. 1115-1126
Author(s):  
M Pereyra ◽  
D Altamirano ◽  
J M C Court ◽  
N Degenaar ◽  
R Wijnands ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Time Scales ◽  
Strong Evidence ◽  
Spectral Properties ◽  
X Ray ◽  
Term Evolution ◽  
Wide Range ◽  
Low Mass

ABSTRACT IGR J17091–3624 is a low-mass X-ray binary (LMXB), which received wide attention from the community thanks to its similarities with the bright black hole system GRS 1915+105. Both systems exhibit a wide range of highly structured X-ray variability during outburst, with time-scales from few seconds to tens of minutes, which make them unique in the study of mass accretion in LMXBs. In this work, we present a general overview into the long-term evolution of IGR J17091–3624, using Swift/XRT observations from the onset of the 2011–2013 outburst in 2011 February till the end of the last bright outburst in 2016 November. We found four re-flares during the decay of the 2011 outburst, but no similar re-flares appear to be present in the latter one. We studied, in detail, the period with the lowest flux observed in the last 10 yr, just at the tail end of the 2011–2013 outburst, using Chandra and XMM-Newton observations. We observed changes in flux as high as a factor of 10 during this period of relative quiescence, without strong evidence of softening in the spectra. This result suggests that the source has not been observed at its true quiescence so far. By comparing the spectral properties at low luminosities of IGR J17091–3624 and those observed for a well-studied population of LMXBs, we concluded that IGR J17091–3624 is most likely to host a black hole as a compact companion rather than a neutron star.

scholarly journals Evolution of the Earth’s atmosphere during Late Veneer accretion

2020 ◽  
Vol 499 (4) ◽  
pp. 5334-5362
Author(s):  
Catriona A Sinclair ◽  
Mark C Wyatt ◽  
Alessandro Morbidelli ◽  
David Nesvorný
Keyword(s):  
Terrestrial Planet ◽  
Hydrodynamic Simulations ◽  
Substantial Growth ◽  
Early Atmosphere ◽  
The Earth ◽  
Wide Range ◽  
History Of ◽  
Current Mass ◽  
Low Mass ◽  
Late Veneer

ABSTRACT Recent advances in our understanding of the dynamical history of the Solar system have altered the inferred bombardment history of the Earth during accretion of the Late Veneer, after the Moon-forming impact. We investigate how the bombardment by planetesimals left-over from the terrestrial planet region after terrestrial planet formation, as well as asteroids and comets, affects the evolution of Earth’s early atmosphere. We develop a new statistical code of stochastic bombardment for atmosphere evolution, combining prescriptions for atmosphere loss and volatile delivery derived from hydrodynamic simulations and theory with results from dynamical modelling of realistic populations of impactors. We find that for an initially Earth-like atmosphere, impacts cause moderate atmospheric erosion with stochastic delivery of large asteroids, giving substantial growth (× 10) in a few ${{\ \rm per\ cent}}$ of cases. The exact change in atmosphere mass is inherently stochastic and dependent on the dynamics of the left-over planetesimals. We also consider the dependence on unknowns including the impactor volatile content, finding that the atmosphere is typically completely stripped by especially dry left-over planetesimals ($\lt 0.02 ~ {{\ \rm per\ cent}}$ volatiles). Remarkably, for a wide range of initial atmosphere masses and compositions, the atmosphere converges towards similar final masses and compositions, i.e. initially low-mass atmospheres grow, whereas massive atmospheres deplete. While the final properties are sensitive to the assumed impactor properties, the resulting atmosphere mass is close to that of current Earth. The exception to this is that a large initial atmosphere cannot be eroded to the current mass unless the atmosphere was initially primordial in composition.

scholarly journals Binding of cardiotonic steroids to Na+,K+-ATPase in the E2P state

2020 ◽  
Vol 118 (1) ◽  
pp. e2020438118
Author(s):  
Ryuta Kanai ◽  
Flemming Cornelius ◽  
Haruo Ogawa ◽  
Kanna Motoyama ◽  
Bente Vilsen ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Conformational Changes ◽  
Ground State ◽  
Sodium Pump ◽  
Structural Features ◽  
Animal Cells ◽  
Inhibitory Potency ◽  
New Members ◽  
Wide Range

The sodium pump (Na+, K+-ATPase, NKA) is vital for animal cells, as it actively maintains Na+ and K+ electrochemical gradients across the cell membrane. It is a target of cardiotonic steroids (CTSs) such as ouabain and digoxin. As CTSs are almost unique strong inhibitors specific to NKA, a wide range of derivatives has been developed for potential therapeutic use. Several crystal structures have been published for NKA-CTS complexes, but they fail to explain the largely different inhibitory properties of the various CTSs. For instance, although CTSs are thought to inhibit ATPase activity by binding to NKA in the E2P state, we do not know if large conformational changes accompany binding, as no crystal structure is available for the E2P state free of CTS. Here, we describe crystal structures of the BeF3− complex of NKA representing the E2P ground state and then eight crystal structures of seven CTSs, including rostafuroxin and istaroxime, two new members under clinical trials, in complex with NKA in the E2P state. The conformations of NKA are virtually identical in all complexes with and without CTSs, showing that CTSs bind to a preformed cavity in NKA. By comparing the inhibitory potency of the CTSs measured under four different conditions, we elucidate how different structural features of the CTSs result in different inhibitory properties. The crystal structures also explain K+-antagonism and suggest a route to isoform specific CTSs.

scholarly journals Allelopathic activity of the picocyanobacterium Synechococcus sp. on unicellular eukaryote planktonic microalgae

2018 ◽  
Vol 69 (9) ◽  
pp. 1472 ◽  
Author(s):  
Sylwia Śliwińska-Wilczewska ◽  
Aldo Barreiro Felpeto ◽  
Jakub Maculewicz ◽  
Amanda Sobczyk ◽  
Vitor Vasconcelos ◽  
...  
Keyword(s):  
Photosynthetic Rate ◽  
Unicellular Eukaryote ◽  
Allelopathic Effect ◽  
Prymnesium Parvum ◽  
Porphyridium Purpureum ◽  
Allelopathic Activity ◽  
Wide Range ◽  
Synechococcus Sp ◽  
Taxonomic Groups ◽  
Allelopathic Compounds

The production and release of allelopathic compounds is an important adaptation by which some species of cyanobacteria can achieve a competitive advantage over other primary producers. In the present study we tested the allelopathic activity of the picocyanobacterium Synechococcus sp. against the following coexisting unicellular eukaryote microalgae: Porphyridium purpureum, Stichococcus bacillaris, Prymnesium parvum and Nitzschia dissipata. With these species, we covered a wide range of taxonomic groups. We demonstrated that both the addition of Synechococcus sp. cell-free filtrate and coculture inhibited the growth, chlorophyll content and photosynthetic rate of P. purpureum and S. bacillaris. Conversely, P. parvum, a well-known mixotroph, was positively affected by both Synechococcus sp. treatments. In contrast, N. dissipata was not affected by either the picocyanobacterial filtrate or coculture. These results suggest that the negative allelopathic effect is related to a reduction in the photosynthetic rate, and that Synechococcus sp. allelopathy should be taken into account in the interactions between picocyanobacteria and eukaryote competitors coexisting in a planktonic system.

scholarly journals Radio and X-ray monitoring of the accreting millisecond X-ray pulsar IGR J17591−2342 in outburst

2019 ◽  
Vol 492 (1) ◽  
pp. 1091-1101 ◽  
Author(s):  
N V Gusinskaia ◽  
T D Russell ◽  
J W T Hessels ◽  
S Bogdanov ◽  
N Degenaar ◽  
...  
Keyword(s):  
Large Scatter ◽  
Millisecond Pulsar ◽  
Radio Luminosity ◽  
Correlation Index ◽  
X Ray ◽  
Wide Range ◽  
Low Mass ◽  
Green Bank Telescope ◽  
Spectral State ◽  
Rule Out

ABSTRACT IGR J17591−2342 is a new accreting millisecond X-ray pulsar that was recently discovered in outburst in 2018. Early observations revealed that the source’s radio emission is brighter than that of any other known neutron star low-mass X-ray binary (NS–LMXB) at comparable X-ray luminosity, and assuming its likely ≳6 kpc distance. It is comparably radio bright to black hole LMXBs at similar X-ray luminosities. In this work, we present the results of our extensive radio and X-ray monitoring campaign of the 2018 outburst of IGR J17591−2342. In total, we collected 10 quasi-simultaneous radio (VLA, ATCA) and X-ray (Swift–XRT) observations, which make IGR J17591−2342 one of the best-sampled NS–LMXBs. We use these to fit a power-law correlation index $\beta = 0.37^{+0.42}_{-0.40}$ between observed radio and X-ray luminosities (LR ∝ LXβ). However, our monitoring revealed a large scatter in IGR J17591−2342’s radio luminosity (at a similar X-ray luminosity, LX ∼1036 erg s−1, and spectral state), with LR ∼ 4 × 1029 erg s−1 during the first three reported observations, and up to a factor of 4 lower LR during later radio observations. None the less, the average radio luminosity of IGR J17591−2342 is still one of the highest among NS–LMXBs, and we discuss possible reasons for the wide range of radio luminosities observed in such systems during outburst. We found no evidence for radio pulsations from IGR J17591−2342 in our Green Bank Telescope observations performed shortly after the source returned to quiescence. None the less, we cannot rule out that IGR J17591−2342 becomes a radio millisecond pulsar during quiescence.

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