scholarly journals Danthonia Spicata (Poaceae) and Atkinsonella Hypoxylon (Balansiae): environmental dependence of a symbiosis

2001 ◽  
Vol 88 (5) ◽  
pp. 903-909 ◽  
Author(s):  
Melissa K. McCormick ◽  
Katherine L. Gross ◽  
Robin A. Smith
Keyword(s):  
Atkinsonella Hypoxylon ◽  
Environmental Dependence ◽  
Danthonia Spicata

PCR‐based detection of the epibiotic fungus Atkinsonella hypoxylon associated with its host grass Danthonia spicata

Crop Science ◽  
2020 ◽  
Vol 60 (3) ◽  
pp. 1660-1665
Author(s):  
Scott E. Warnke
Keyword(s):  
Atkinsonella Hypoxylon ◽  
Danthonia Spicata

Transmission of Atkinsonella hypoxylon (Clavicipitaceae) by cleistogamous seed of Danthonia spicata (Gramineae)

1984 ◽  
Vol 62 (12) ◽  
pp. 2893-2895 ◽  
Author(s):  
Keith Clay ◽  
J. P. Jones
Keyword(s):  
Chasmogamous Flowers ◽  
Atkinsonella Hypoxylon ◽  
Danthonia Spicata

Atkinsonella hypoxylon is a systemic parasite of the grasses Danthonia spicata, D. compressa, and Stipa leucotricha. The means by which this fungus and other Balansiae (Balansia, Balansiopsis, Epichloë, and Myriogenospora) are transmitted from one plant to another is poorly understood. Host grasses of A. hypoxylon normally produce spikelets of open, wind-pollinated chasmogamous flowers at the apex of the flowering culm and spikelets of self-pollinated cleistogamous flowers in the lower leaf sheaths of the same culm. Plants of D. spicata infected by A. hypoxylon regularly produce cleistogamous spikelets in the lowermost leaf sheaths, although chasmogamous spikelets are aborted by hypothallus development. Embryos of the seeds resulting from these flowers were surrounded by hyphae. The seeds were germinated and when the plants flowered, they produced deformed flowering culms and hypothalli, indicating that A. hypoxylon is transmitted from parent to offspring through cleistogamous seed.

scholarly journals Evolution: Environmental Dependence of the Mutational Process

2019 ◽  
Vol 29 (11) ◽  
pp. R415-R417
Author(s):  
Charles F. Baer
Keyword(s):  
Mutational Process ◽  
Environmental Dependence

scholarly journals First Light And Reionization Epoch Simulations (FLARES) – I. Environmental dependence of high-redshift galaxy evolution

2020 ◽  
Vol 500 (2) ◽  
pp. 2127-2145
Author(s):  
Christopher C Lovell ◽  
Aswin P Vijayan ◽  
Peter A Thomas ◽  
Stephen M Wilkins ◽  
David J Barnes ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Dynamic Range ◽  
High Redshift ◽  
Formation Rate ◽  
Mass Function ◽  
Distribution Functions ◽  
Large Area ◽  
Composite Distribution ◽  
Environmental Dependence

ABSTRACT We introduce the First Light And Reionisation Epoch Simulations (FLARES), a suite of zoom simulations using the EAGLE model. We resimulate a range of overdensities during the Epoch of Reionization (EoR) in order to build composite distribution functions, as well as explore the environmental dependence of galaxy formation and evolution during this critical period of galaxy assembly. The regions are selected from a large $(3.2 \, \mathrm{cGpc})^{3}$ parent volume, based on their overdensity within a sphere of radius 14 h−1 cMpc. We then resimulate with full hydrodynamics, and employ a novel weighting scheme that allows the construction of composite distribution functions that are representative of the full parent volume. This significantly extends the dynamic range compared to smaller volume periodic simulations. We present an analysis of the galaxy stellar mass function (GSMF), the star formation rate distribution function (SFRF), and the star-forming sequence (SFS) predicted by FLARES, and compare to a number of observational and model constraints. We also analyse the environmental dependence over an unprecedented range of overdensity. Both the GSMF and the SFRF exhibit a clear double-Schechter form, up to the highest redshifts (z = 10). We also find no environmental dependence of the SFS normalization. The increased dynamic range probed by FLARES will allow us to make predictions for a number of large area surveys that will probe the EoR in coming years, carried out on new observatories such as Roman and Euclid.

scholarly journals The weak imprint of environment on the stellar populations of galaxies

2020 ◽  
Vol 500 (4) ◽  
pp. 4469-4490 ◽  
Author(s):  
James Trussler ◽  
Roberto Maiolino ◽  
Claudia Maraston ◽  
Yingjie Peng ◽  
Daniel Thomas ◽  
...  
Keyword(s):  
Environmental Effects ◽  
Unique Feature ◽  
Stellar Populations ◽  
Stellar Mass ◽  
Sloan Digital Sky Survey ◽  
Star Forming ◽  
Sky Survey ◽  
Satellite Galaxies ◽  
Projected Distance ◽  
Environmental Dependence

ABSTRACT We investigate the environmental dependence of the stellar populations of galaxies in Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Echoing earlier works, we find that satellites are both more metal-rich (<0.1 dex) and older (<2 Gyr) than centrals of the same stellar mass. However, after separating star-forming, green valley, and passive galaxies, we find that the true environmental dependence of both stellar metallicity (<0.03 dex) and age (<0.5 Gyr) is in fact much weaker. We show that the strong environmental effects found when galaxies are not differentiated result from a combination of selection effects brought about by the environmental dependence of the quenched fraction of galaxies, and thus we strongly advocate for the separation of star-forming, green valley, and passive galaxies when the environmental dependence of galaxy properties are investigated. We also study further environmental trends separately for both central and satellite galaxies. We find that star-forming galaxies show no environmental effects, neither for centrals nor for satellites. In contrast, the stellar metallicities of passive and green valley satellites increase weakly (<0.05 and <0.08 dex, respectively) with increasing halo mass, increasing local overdensity and decreasing projected distance from their central; this effect is interpreted in terms of moderate environmental starvation (‘strangulation’) contributing to the quenching of satellite galaxies. Finally, we find a unique feature in the stellar mass–stellar metallicity relation for passive centrals, where galaxies in more massive haloes have larger stellar mass (∼0.1 dex) at constant stellar metallicity; this effect is interpreted in terms of dry merging of passive central galaxies and/or progenitor bias.

scholarly journals ENVIRONMENTAL DEPENDENCE OF ACTIVE GALACTIC NUCLEUS ACTIVITY. I. THE EFFECTS OF HOST GALAXY

2009 ◽  
Vol 699 (2) ◽  
pp. 1679-1689 ◽  
Author(s):  
Yun-Young Choi ◽  
Jong-Hak Woo ◽  
Changbom Park
Keyword(s):  
Active Galactic Nucleus ◽  
Host Galaxy ◽  
Environmental Dependence

Embracing variability: environmental dependence and plant community context in ecological restoration

2015 ◽  
Vol 24 (1) ◽  
pp. 119-127 ◽  
Author(s):  
Sara Jo M. Dickens ◽  
Seema Mangla ◽  
Kristine L. Preston ◽  
Katherine N. Suding
Keyword(s):  
Ecological Restoration ◽  
Plant Community ◽  
Community Context ◽  
Environmental Dependence

scholarly journals Environmental changes dictate selection and nonspecific epistasis in an empirical phenotype-environment-fitness landscape

2021 ◽  
Author(s):  
J.Z. Chen ◽  
D.M. Fowler ◽  
N. Tokuriki
Keyword(s):  
Selection Pressure ◽  
Evolutionary Dynamics ◽  
Environmental Changes ◽  
Fitness Landscape ◽  
Resistance Level ◽  
Phenotypic Changes ◽  
Environmental Selection ◽  
Selection Environment ◽  
Data Points ◽  
Environmental Dependence

SummaryThe fitness landscape, a function that maps genotypic and phenotypic changes to their effects on fitness, is an invaluable concept in evolutionary biochemistry. Though widely discussed, measurements of phenotype-fitness landscapes in proteins remain scarce. Here, we quantify all single mutational effects on fitness and phenotype (antibiotic resistance level) of VIM-2 β-lactamase (5600 variants) across a 64-fold range of ampicillin concentrations by deep mutational scanning. We then construct a phenotype-fitness landscape that takes variations in environmental selection pressure into account (a phenotype-environment-fitness landscape). We found that a simple, empirical landscape accurately models the ~39,000 mutational data points, which suggests the evolution of VIM-2 can be predicted based on the selection environment. Our landscape provides new quantitative knowledge on the evolution of the β-lactamases and proteins in general, particularly their evolutionary dynamics under sub-inhibitory antibiotic concentrations, as well as the mechanisms and environmental dependence of nonspecific epistasis.

scholarly journals An environmental dependence of the physical and structural properties in the Hydra cluster galaxies

2020 ◽  
Vol 500 (1) ◽  
pp. 1323-1339
Author(s):  
Ciria Lima-Dias ◽  
Antonela Monachesi ◽  
Sergio Torres-Flores ◽  
Arianna Cortesi ◽  
Daniel Hernández-Lang ◽  
...  
Keyword(s):  
Structural Properties ◽  
Clustering Algorithm ◽  
Spatial Clustering ◽  
Broad Band ◽  
Visible Region ◽  
Early Type ◽  
Cluster Galaxies ◽  
Using Data ◽  
Stellar Masses ◽  
Environmental Dependence

ABSTRACT The nearby Hydra cluster (∼50 Mpc) is an ideal laboratory to understand, in detail, the influence of the environment on the morphology and quenching of galaxies in dense environments. We study the Hydra cluster galaxies in the inner regions (1R200) of the cluster using data from the Southern Photometric Local Universe Survey, which uses 12 narrow and broad-band filters in the visible region of the spectrum. We analyse structural (Sérsic index, effective radius) and physical (colours, stellar masses, and star formation rates) properties. Based on this analysis, we find that ∼88 per cent of the Hydra cluster galaxies are quenched. Using the Dressler–Schectman test approach, we also find that the cluster shows possible substructures. Our analysis of the phase-space diagram together with density-based spatial clustering algorithm indicates that Hydra shows an additional substructure that appears to be in front of the cluster centre, which is still falling into it. Our results, thus, suggest that the Hydra cluster might not be relaxed. We analyse the median Sérsic index as a function of wavelength and find that for red [(u − r) ≥2.3] and early-type galaxies it displays a slight increase towards redder filters (13 and 18 per cent, for red and early type, respectively), whereas for blue + green [(u − r)<2.3] galaxies it remains constant. Late-type galaxies show a small decrease of the median Sérsic index towards redder filters. Also, the Sérsic index of galaxies, and thus their structural properties, do not significantly vary as a function of clustercentric distance and density within the cluster; and this is the case regardless of the filter.

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