ENVIRONMENTAL PERTURBATIONS CAUSED BY ASTEROID IMPACTS

AbstractLiving cells actively migrate in their environment to perform key biological functions—from unicellular organisms looking for food to single cells such as fibroblasts, leukocytes or cancer cells that can shape, patrol or invade tissues. Cell migration results from complex intracellular processes that enable cell self-propulsion, and has been shown to also integrate various chemical or physical extracellular signals. While it is established that cells can modify their environment by depositing biochemical signals or mechanically remodelling the extracellular matrix, the impact of such self-induced environmental perturbations on cell trajectories at various scales remains unexplored. Here, we show that cells can retrieve their path: by confining motile cells on 1D and 2D micropatterned surfaces, we demonstrate that they leave long-lived physicochemical footprints along their way, which determine their future path. On this basis, we argue that cell trajectories belong to the general class of self-interacting random walks, and show that self-interactions can rule large scale exploration by inducing long-lived ageing, subdiffusion and anomalous first-passage statistics. Altogether, our joint experimental and theoretical approach points to a generic coupling between motile cells and their environment, which endows cells with a spatial memory of their path and can dramatically change their space exploration.

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Long-term effects of abrupt environmental perturbations in model of group chase and escape with the presence of non-conservative processes

Physica A Statistical Mechanics and its Applications ◽

10.1016/j.physa.2021.126156 ◽

2021 ◽

pp. 126156

Author(s):

J.R. Šćepanović ◽

Z.M. Jakšić ◽

Lj. Budinski-Petković ◽

S.B. Vrhovac

Keyword(s):

Long Term Effects ◽

Environmental Perturbations

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Adaptation of turnip mosaic potyvirus to a specific niche reduces its genetic and environmental robustness

Virus Evolution ◽

10.1093/ve/veaa041 ◽

2020 ◽

Vol 6 (2) ◽

Author(s):

Anamarija Butković ◽

Rubén González ◽

Inés Cobo ◽

Santiago F Elena

Keyword(s):

Mutation Rates ◽

Permissive Temperature ◽

Fitness Component ◽

Temperature Conditions ◽

Environmental Perturbations ◽

Genetic Robustness ◽

Congruence Theory ◽

The Face ◽

Environmental Robustness ◽

Two Sides

Abstract Robustness is the preservation of the phenotype in the face of genetic and environmental perturbations. It has been argued that robustness must be an essential fitness component of RNA viruses owed to their small and compacted genomes, high mutation rates and living in ever-changing environmental conditions. Given that genetic robustness might hamper possible beneficial mutations, it has been suggested that genetic robustness can only evolve as a side-effect of the evolution of robustness mechanisms specific to cope with environmental perturbations, a theory known as plastogenetic congruence. However, empirical evidences from different viral systems are contradictory. To test how adaptation to a particular environment affects both environmental and genetic robustness, we have used two strains of turnip mosaic potyvirus (TuMV) that differ in their degree of adaptation to Arabidopsis thaliana at a permissive temperature. We show that the highly adapted strain is strongly sensitive to the effect of random mutations and to changes in temperature conditions. In contrast, the non-adapted strain shows more robustness against both the accumulation of random mutations and drastic changes in temperature conditions. Together, these results are consistent with the predictions of the plastogenetic congruence theory, suggesting that genetic and environmental robustnesses may be two sides of the same coin for TuMV.

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Dynamical Analysis of bantam-Regulated Drosophila Circadian Rhythm Model

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127414501612 ◽

2014 ◽

Vol 24 (12) ◽

pp. 1450161 ◽

Cited By ~ 1

Author(s):

Ying Li ◽

Zengrong Liu

Keyword(s):

Circadian Rhythm ◽

Crucial Role ◽

Target Genes ◽

Classical Model ◽

Dynamical Analysis ◽

Biological Processes ◽

Biological Mechanisms ◽

Environmental Perturbations ◽

Dynamical Behaviors ◽

Important Regulator

MicroRNAs (miRNAs) interact with 3′untranslated region (UTR) elements of target genes to regulate mRNA stability or translation, and play a crucial role in regulating many different biological processes. bantam, a conserved miRNA, is involved in several functions, such as regulating Drosophila growth and circadian rhythm. Recently, it has been discovered that bantam plays a crucial role in the core circadian pacemaker. In this paper, based on experimental observations, a detailed dynamical model of bantam-regulated circadian clock system is developed to show the post-transcriptional behaviors in the modulation of Drosophila circadian rhythm, in which the regulation of bantam is incorporated into a classical model. The dynamical behaviors of the model are consistent with the experimental observations, which shows that bantam is an important regulator of Drosophila circadian rhythm. The sensitivity analysis of parameters demonstrates that with the regulation of bantam the system is more sensitive to perturbations, indicating that bantam regulation makes it easier for the organism to modulate its period against the environmental perturbations. The effectiveness in rescuing locomotor activity rhythms of mutated flies shows that bantam is necessary for strong and sustained rhythms. In addition, the biological mechanisms of bantam regulation are analyzed, which may help us more clearly understand Drosophila circadian rhythm regulated by other miRNAs.

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The hypoxia that developed in a microtidal estuary following an extreme storm produced dramatic changes in the benthos

Marine and Freshwater Research ◽

10.1071/mf14216 ◽

2016 ◽

Vol 67 (3) ◽

pp. 327 ◽

Cited By ~ 37

Author(s):

James R. Tweedley ◽

Chris S. Hallett ◽

Richard M. Warwick ◽

K. Robert Clarke ◽

Ian C. Potter

Keyword(s):

Species Composition ◽

Environmental Stress ◽

Benthic Macroinvertebrates ◽

Total Density ◽

Taxonomic Distinctness ◽

Residence Times ◽

Number Of Species ◽

Environmental Perturbations ◽

Extreme Storm ◽

Evenness Index

Runoff from an extreme storm on 22 March 2010 led, during the next 3 months, to the formation of a pronounced halocline and underlying hypoxia in the upper reaches of the microtidal Swan–Canning Estuary. Benthic macroinvertebrates were sampled between January 2010 and October 2011 at five sites along 10km of this region. By mid-April, the number of species, total density, Simpson’s evenness index and taxonomic distinctness had declined markedly, crustaceans had disappeared and the densities of annelids and molluscs had declined slightly. These faunal attributes (except Simpson’s index) and species composition did not recover until after the end of the hypoxia. The survival of annelids and loss of crustaceans in this period reflects different sensitivities of these taxa to severe environmental stress. The results emphasise that microtidal estuaries with long residence times are highly vulnerable to the effects of environmental perturbations, particularly during warmer periods of the year.

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Trouble in Paradise? A comparison of 1953 and 2005 benthonic foraminiferal seafloor assemblages at the Ibis Field, offshore eastern Trinidad, West Indies

Journal of Micropalaeontology ◽

10.1144/jm.25.2.157 ◽

2006 ◽

Vol 25 (2) ◽

pp. 157-164 ◽

Cited By ~ 7

Author(s):

Brent Wilson

Keyword(s):

Relative Abundance ◽

Nutrient Enrichment ◽

Abundant Species ◽

Nutrient Supply ◽

South American ◽

Sufficient Time ◽

Phytoplankton Primary Production ◽

Environmental Perturbations ◽

Run Off ◽

Shrimp Farms

Abstract. Foraminiferal communities are not static, but change in response to environmental perturbations. Given sufficient time, the change will be recorded in the total (live+dead) seafloor assemblage, from which valuable information regarding environmental trends can be obtained by re-sampling assemblages at the decadal scale.The seafloor assemblage in the 5 km × 6 km Ibis Field, off southeast Trinidad, first surveyed in 1953, was re-examined in 2005. The fauna had changed markedly between the surveys. Overall increases in the proportional abundances of Uvigerina subperegrina, Ammonia pauciloculata/Rolhausenia rolhauseni and Pseudononion atlanticum indicate an increase in nutrient supply that apparently killed off Cibicidoides pseudoungerianus and Miliolinella subrotunda, and reduced the relative abundance of Hanzawaia concentrica, but did not affect the relative abundance of Cancris sagrai. As shown by similar 1953 and 2005 planktonic/benthonic foraminiferal ratios, the increased nutrient supply impacted on both surface and bottom waters.Of the six most abundant species in 2005, five showed the same general biogeographical distributions within the field in 1953 and 2005. However, whereas the proportional abundance of Uvigerina subperegrina in 1953 increased southwards, in 2005 it increased northwards.Trinidad cannot be the source for the nutrient enrichment: the island lies down-current from the Ibis Field. Sources must therefore be sought up-current and to the southeast, in the Amazon, Essequibo and Orinoco river basins, or along the South American shoreline. It is speculated that the nutrient enrichment may be a consequence of increased phytoplankton primary production associated with nitrogen-rich run-off from South American sugarcane plantations, or from flushing of organic carbon from poorly regulated sewage systems or shrimp farms in South America.

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