scholarly journals Tardigrades exhibit robust inter-limb coordination across walking speeds

2021 ◽  
Author(s):  
Jasmine A Nirody ◽  
Lisset A. Duran ◽  
Deborah Johnston ◽  
Daniel J. Cohen
Keyword(s):  
Optimal Strategy ◽  
Environmental Changes ◽  
Small Animals ◽  
Locomotor Control ◽  
Limb Coordination ◽  
Fluctuating Environments ◽  
Leg Coordination ◽  
Key Features ◽  
Control Circuits ◽  
Walking Speeds

AbstractTardigrades must negotiate heterogeneous, fluctuating environments, and accordingly utilize locomotive strategies capable of dealing with variable terrain. We analyze the kinematics and inter-leg coordination of freely walking tardigrades (species: Hypsibius dujardini). We find that tardigrade walking replicates several key features of walking in insects despite disparities in size, skeleton, and habitat. To test the effect of environmental changes on tardigrade locomotor control circuits, we measure kinematics and inter-leg coordination during walking on two substrates of different stiffnesses. We find that the phase offset between contralateral leg pairs is flexible, while ipsilateral coordination is preserved across environmental conditions. This mirrors similar results in insects and crustaceans. We propose that these functional similarities in walking co-ordination between tardigrades and arthropods is either due to a generalized locomotor control circuit common to panarthropods, or to independent convergence onto an optimal strategy for robust multi-legged control in small animals with simple circuitry. Our results highlight the value of tardigrades as a comparative system towards understanding the mechanisms – neural and/or mechanical – underlying coordination in panarthropod locomotion.

scholarly journals Tardigrades exhibit robust interlimb coordination across walking speeds and terrains

2021 ◽  
Vol 118 (35) ◽  
pp. e2107289118
Author(s):  
Jasmine A. Nirody ◽  
Lisset A. Duran ◽  
Deborah Johnston ◽  
Daniel J. Cohen
Keyword(s):  
Environmental Conditions ◽  
Optimal Strategy ◽  
Environmental Changes ◽  
Control Circuit ◽  
Small Animals ◽  
Locomotor Control ◽  
Fluctuating Environments ◽  
Key Features ◽  
Control Circuits ◽  
Walking Speeds

Tardigrades must negotiate heterogeneous, fluctuating environments and accordingly utilize locomotive strategies capable of dealing with variable terrain. We analyze the kinematics and interleg coordination of freely walking tardigrades (species: Hypsibius exemplaris). We find that tardigrade walking replicates several key features of walking in insects despite disparities in size, skeleton, and habitat. To test the effect of environmental changes on tardigrade locomotor control circuits we measure kinematics and interleg coordination during walking on two substrates of different stiffnesses. We find that the phase offset between contralateral leg pairs is flexible, while ipsilateral coordination is preserved across environmental conditions. This mirrors similar results in insects and crustaceans. We propose that these functional similarities in walking coordination between tardigrades and arthropods is either due to a generalized locomotor control circuit common to panarthropods or to independent convergence onto an optimal strategy for robust multilegged control in small animals with simple circuitry. Our results highlight the value of tardigrades as a comparative system toward understanding the mechanisms—neural and/or mechanical—underlying coordination in panarthropod locomotion.

scholarly journals Antibiotics shift the temperature response curve of Escherichia coli growth

2020 ◽  
Author(s):  
Mauricio Cruz-Loya ◽  
Elif Tekin ◽  
Tina Manzhu Kang ◽  
Alejandra Rodriguez-Verdugo ◽  
Van M. Savage ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Throughput Screening ◽  
Environmental Changes ◽  
Temperature Response ◽  
Thermal Response ◽  
Ecological Systems ◽  
Environmental Stressors ◽  
Optimal Temperature ◽  
Key Features ◽  
Temperature Responses

AbstractTemperature variation—through time and across climatic gradients—affects individuals, populations, and communities. Yet how the thermal response of biological systems is altered by environmental stressors is poorly understood. Here we quantify two key features—optimal temperature and temperature breadth—to investigate how temperature responses vary in the presence of antibiotics. We use high-throughput screening to measure growth of Escherichia coli under single and pairwise combinations of 12 antibiotics across seven temperatures that range from 22°C to 46°C. We find that antibiotic stress often results in considerable changes in the optimal temperature for growth and a narrower temperature breadth. The direction of the optimal temperature shifts can be explained by the similarities between antibiotic-induced and temperature-induced damage to the physiology of the bacterium. We also find that the effects of pairs of stressors in the temperature response can often be explained by just one antibiotic out of the pair. Our study has implications for a general understanding of how ecological systems adapt and evolve to environmental changes.

scholarly journals Tegotae-Based Control Produces Adaptive Inter- and Intra-limb Coordination in Bipedal Walking

2021 ◽  
Vol 15 ◽  
Author(s):  
Dai Owaki ◽  
Shun-ya Horikiri ◽  
Jun Nishii ◽  
Akio Ishiguro
Keyword(s):  
Central Pattern Generator ◽  
Environmental Changes ◽  
Sensory Information ◽  
Motor Command ◽  
Pattern Generator ◽  
Bipedal Walking ◽  
Walking Robots ◽  
Two Dimensional ◽  
Limb Coordination ◽  
Systematic Methodology

Despite the appealing concept of central pattern generator (CPG)-based control for bipedal walking robots, there is currently no systematic methodology for designing a CPG-based controller. To remedy this oversight, we attempted to apply the Tegotae approach, a Japanese concept describing how well a perceived reaction, i.e., sensory information, matches an expectation, i.e., an intended motor command, in designing localised controllers in the CPG-based bipedal walking model. To this end, we developed a Tegotae function that quantifies the Tegotae concept. This function allowed incorporating decentralised controllers into the proposed bipedal walking model systematically. We designed a two-dimensional bipedal walking model using Tegotae functions and subsequently implemented it in simulations to validate the proposed design scheme. We found that our model can walk on both flat and uneven terrains and confirmed that the application of the Tegotae functions in all joint controllers results in excellent adaptability to environmental changes.

scholarly journals Adaptive diversification in the cellular circadian behavior of Arabidopsis leaf- and root-derived cells

2021 ◽  
Author(s):  
Shunji Nakamura ◽  
Tokitaka Oyama
Keyword(s):  
Environmental Changes ◽  
Cell Types ◽  
Cellular Level ◽  
Circadian System ◽  
Circadian Clocks ◽  
Intrinsic Properties ◽  
Adaptive Diversification ◽  
Local Environments ◽  
Fluctuating Environments ◽  
Circadian Behavior

The plant circadian system is based on self-sustained cellular oscillations and is utilized to adapt to daily and seasonal environmental changes. The cellular circadian clocks in the above- and belowground plant organs are subjected to diverse local environments. Individual cellular clocks are affected by other cells/tissues in plants, and the intrinsic properties of cellular clocks remain to be elucidated. In this study, we showed the circadian properties of leaf- and root-derived cells of a CCA1::LUC Arabidopsis transgenic plant and demonstrated that the cells in total isolation from other cells harbor a genuine circadian clock. Quantitative and statistical analyses for individual cellular bioluminescence rhythms revealed a difference in amplitude and precision of light/dark entrainment between the two cell-types, suggesting that leaf-derived cells have a clock with a stronger persistence against fluctuating environments. Circadian systems in the leaves and roots are diversified to adapt to their local environments at the cellular level.

scholarly journals Contributions of spatial and temporal control of step length symmetry in the transfer of locomotor adaptation from a motorized to a non-motorized split-belt treadmill

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
Daniel L. Gregory ◽  
Frank C. Sup ◽  
Julia T. Choi
Keyword(s):  
Step Length ◽  
Treadmill Walking ◽  
Speed Ratio ◽  
Foot Placement ◽  
After Effects ◽  
Locomotor Adaptation ◽  
Locomotor Control ◽  
Length Difference ◽  
Limb Coordination ◽  
Healthy Participants

Walking requires control of where and when to step for stable interlimb coordination. Motorized split-belt treadmills which constrain each leg to move at different speeds lead to adaptive changes to limb coordination that result in after-effects (e.g. gait asymmetry) on return to normal treadmill walking. These after-effects indicate an underlying neural adaptation. Here, we assessed the transfer of motorized split-belt treadmill adaptations with a custom non-motorized split-belt treadmill where each belt can be self-propelled at different speeds. Transfer was indicated by the presence of after-effects in step length, foot placement and step timing differences. Ten healthy participants adapted on a motorized split-belt treadmill (2 : 1 speed ratio) and were then assessed for after-effects during subsequent non-motorized treadmill and motorized tied-belt treadmill walking. We found that after-effects in step length difference during transfer to non-motorized split-belt walking were primarily associated with step time differences. Conversely, residual after-effects during motorized tied-belt walking following transfer were associated with foot placement differences. Our data demonstrate decoupling of adapted spatial and temporal locomotor control during transfer to a novel context, suggesting that foot placement and step timing control can be independently modulated during walking.

Modeling the transmission of Buruli ulcer in fluctuating environments

2017 ◽  
Vol 10 (05) ◽  
pp. 1750063 ◽  
Author(s):  
Belthasara Assan ◽  
Farai Nyabadza ◽  
Pietro Landi ◽  
Cang Hui
Keyword(s):  
Disease Transmission ◽  
Environmental Changes ◽  
Deterministic Model ◽  
Reproduction Number ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans ◽  
Fluctuating Environments ◽  
Number Formula ◽  
Control And Management ◽  
Transmission Pathways

The transmission dynamics of Buruli ulcer (BU) largely depends on environmental changes. In this paper a deterministic model for the transmission of BU in fluctuating environments is proposed. The model incorporates periodicity in the disease transmission pathways and the Mycobacterium ulcerans density that are thought to vary seasonally. Two reproduction numbers, the time-averaged reproduction number [Formula: see text] and the basic reproduction number [Formula: see text], are determined and compared. It is shown that the time-averaged reproduction underestimates the number of infections. Numerical simulations confirmed that if [Formula: see text] the infection is sustained seasonally. The model outcome suggests that environmental fluctuations should be taken into consideration in designing policies aimed at BU control and management.

scholarly journals On the importance of being stable ‒ evolutionarily frozen species can win in fluctuating environment

2017 ◽  
Author(s):  
Jaroslav Flegr ◽  
Petr Ponížil
Keyword(s):  
Interspecific Competition ◽  
Parameter Space ◽  
Environmental Changes ◽  
Rare Events ◽  
Stochastic Modelling ◽  
Broad Area ◽  
Transient Change ◽  
Asexual Species ◽  
Fluctuating Environments ◽  
Probability Of Extinction

AbstractThe ability of organisms to adaptively respond to environmental changes (evolvability) is usually considered to be an important advantage in interspecific competition. It has been suggested, however, that evolvability could be a double-edged sword that could present a serious handicap in fluctuating environments. The authors of this counterintuitive idea have published only verbal models to support their claims.Here we present the results of individual-based stochastic modelling of competition between two asexual species differing only by their evolvability. They show that, in changeable environments, less evolvable species could outperform their more evolvable competitors in a broad area of a parameter space, regardless of whether the conditions fluctuated periodically or aperiodically. Highly evolvable species prospered better nearly all the time; however, they sustained a higher probability of extinction during rare events of the rapid transient change of conditions.Our results offer an explanation of why sexually reproducing species, with their reduced capacity to respond adaptively to local or temporal environmental changes, prevail in most eukaryotic taxa in nearly all biotopes on the surface of Earth. These species may suffer several important disadvantages in direct competitive battles with asexual species; however, they might win in changeable environments in the more important sorting-according-to-stability war.

Linking transcription, RNA polymerase II elongation and alternative splicing

2020 ◽  
Vol 477 (16) ◽  
pp. 3091-3104 ◽  
Author(s):  
Luciana E. Giono ◽  
Alberto R. Kornblihtt
Keyword(s):  
Gene Expression ◽  
Alternative Splicing ◽  
Rna Polymerase Ii ◽  
Environmental Changes ◽  
Transcription Elongation ◽  
Single Gene ◽  
Regulation Of Gene Expression ◽  
Regulation Of Transcription ◽  
Stepping Stones ◽  
Eukaryotic Transcription

Gene expression is an intricately regulated process that is at the basis of cell differentiation, the maintenance of cell identity and the cellular responses to environmental changes. Alternative splicing, the process by which multiple functionally distinct transcripts are generated from a single gene, is one of the main mechanisms that contribute to expand the coding capacity of genomes and help explain the level of complexity achieved by higher organisms. Eukaryotic transcription is subject to multiple layers of regulation both intrinsic — such as promoter structure — and dynamic, allowing the cell to respond to internal and external signals. Similarly, alternative splicing choices are affected by all of these aspects, mainly through the regulation of transcription elongation, making it a regulatory knob on a par with the regulation of gene expression levels. This review aims to recapitulate some of the history and stepping-stones that led to the paradigms held today about transcription and splicing regulation, with major focus on transcription elongation and its effect on alternative splicing.

Seeking to uncover biology's chemical roots

2019 ◽  
Vol 3 (5) ◽  
pp. 435-443 ◽  
Author(s):  
Addy Pross
Keyword(s):  
Environmental Changes ◽  
Biological Systems ◽  
Significant Development ◽  
The Road ◽  
Physical Chemical ◽  
Systems Chemistry ◽  
Biological World ◽  
Inanimate Matter ◽  
The Origin Of Life ◽  
Opening Up

Despite the considerable advances in molecular biology over the past several decades, the nature of the physical–chemical process by which inanimate matter become transformed into simplest life remains elusive. In this review, we describe recent advances in a relatively new area of chemistry, systems chemistry, which attempts to uncover the physical–chemical principles underlying that remarkable transformation. A significant development has been the discovery that within the space of chemical potentiality there exists a largely unexplored kinetic domain which could be termed dynamic kinetic chemistry. Our analysis suggests that all biological systems and associated sub-systems belong to this distinct domain, thereby facilitating the placement of biological systems within a coherent physical/chemical framework. That discovery offers new insights into the origin of life process, as well as opening the door toward the preparation of active materials able to self-heal, adapt to environmental changes, even communicate, mimicking what transpires routinely in the biological world. The road to simplest proto-life appears to be opening up.

Variance of Subcultures: A Comparison of Walking Speeds in a Midwestern Rural Community

1999 ◽  
Author(s):  
Pamela R. Tenney ◽  
Michelle L. Spurlock ◽  
Susan J. Shapiro
Keyword(s):  
Rural Community ◽  
Walking Speeds
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