scholarly journals Kinematics Governing Mechanotransduction in the Sensory Hair of the Venus flytrap

2020 ◽  
Vol 22 (1) ◽  
pp. 280
Author(s):  
Eashan Saikia ◽  
Nino F. Läubli ◽  
Jan T. Burri ◽  
Markus Rüggeberg ◽  
Christian M. Schlepütz ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Shape ◽  
Electrical Response ◽  
Mechanical Stimulus ◽  
Sensory Cells ◽  
Multi Scale ◽  
Venus Flytrap ◽  
Dionaea Muscipula ◽  
Hair Model ◽  
Touch Stimulus

Insects fall prey to the Venus flytrap (Dionaea muscipula) when they touch the sensory hairs located on the flytrap lobes, causing sudden trap closure. The mechanical stimulus imparted by the touch produces an electrical response in the sensory cells of the trigger hair. These cells are found in a constriction near the hair base, where a notch appears around the hair’s periphery. There are mechanosensitive ion channels (MSCs) in the sensory cells that open due to a change in membrane tension; however, the kinematics behind this process is unclear. In this study, we investigate how the stimulus acts on the sensory cells by building a multi-scale hair model, using morphometric data obtained from μ-CT scans. We simulated a single-touch stimulus and evaluated the resulting cell wall stretch. Interestingly, the model showed that high stretch values are diverted away from the notch periphery and, instead, localized in the interior regions of the cell wall. We repeated our simulations for different cell shape variants to elucidate how the morphology influences the location of these high-stretch regions. Our results suggest that there is likely a higher mechanotransduction activity in these ’hotspots’, which may provide new insights into the arrangement and functioning of MSCs in the flytrap.

scholarly journals Mechanical factors contributing to the Venus flytrap’s rate-dependent response to stimuli

2021 ◽  
Author(s):  
Eashan Saikia ◽  
Nino F. Läubli ◽  
Hannes Vogler ◽  
Markus Rüggeberg ◽  
Hans J. Herrmann ◽  
...  
Keyword(s):  
Fluid Transport ◽  
Angular Displacement ◽  
Mechanical Stimulus ◽  
Cellular Level ◽  
Sensory Cells ◽  
Mechanical Stimuli ◽  
Multi Scale ◽  
Rate Dependent ◽  
Dionaea Muscipula ◽  
Mechanical Factors

AbstractThe sensory hairs of the Venus flytrap (Dionaea muscipula Ellis) detect mechanical stimuli imparted by their prey and fire bursts of electrical signals called action potentials (APs). APs are elicited when the hairs are sufficiently stimulated and two consecutive APs can trigger closure of the trap. Earlier experiments have identified thresholds for the relevant stimulus parameters, namely the angular displacement $$\theta $$ θ and angular velocity $$\omega $$ ω . However, these experiments could not trace the deformation of the trigger hair’s sensory cells, which are known to transduce the mechanical stimulus. To understand the kinematics at the cellular level, we investigate the role of two relevant mechanical phenomena: viscoelasticity and intercellular fluid transport using a multi-scale numerical model of the sensory hair. We hypothesize that the combined influence of these two phenomena and $$\omega $$ ω contribute to the flytrap’s rate-dependent response to stimuli. In this study, we firstly perform sustained deflection tests on the hair to estimate the viscoelastic material properties of the tissue. Thereafter, through simulations of hair deflection tests at different loading rates, we were able to establish a multi-scale kinematic link between $$\omega $$ ω and the cell wall stretch $$\delta $$ δ . Furthermore, we find that the rate at which $$\delta $$ δ evolves during a stimulus is also proportional to $$\omega $$ ω . This suggests that mechanosensitive ion channels, expected to be stretch-activated and localized in the plasma membrane of the sensory cells, could be additionally sensitive to the rate at which stretch is applied.

scholarly journals Probing bacterial cell wall growth by tracing wall-anchored protein complexes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yi-Jen Sun ◽  
Fan Bai ◽  
An-Chi Luo ◽  
Xiang-Yu Zhuang ◽  
Tsai-Shun Lin ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Shape ◽  
Bernoulli Shift ◽  
Protein Complexes ◽  
Axial Direction ◽  
Cell Wall Growth ◽  
Flagellar Motors ◽  
Shift Map ◽  
Dynamic Assembly ◽  
Wall Growth

AbstractThe dynamic assembly of the cell wall is key to the maintenance of cell shape during bacterial growth. Here, we present a method for the analysis of Escherichia coli cell wall growth at high spatial and temporal resolution, which is achieved by tracing the movement of fluorescently labeled cell wall-anchored flagellar motors. Using this method, we clearly identify the active and inert zones of cell wall growth during bacterial elongation. Within the active zone, the insertion of newly synthesized peptidoglycan occurs homogeneously in the axial direction without twisting of the cell body. Based on the measured parameters, we formulate a Bernoulli shift map model to predict the partitioning of cell wall-anchored proteins following cell division.

scholarly journals Action potentials induce biomagnetic fields in carnivorous Venus flytrap plants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anne Fabricant ◽  
Geoffrey Z. Iwata ◽  
Sönke Scherzer ◽  
Lykourgos Bougas ◽  
Katharina Rolfs ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Action Potentials ◽  
Plant Stress ◽  
Optically Pumped ◽  
Long Distance ◽  
Noninvasive Diagnostics ◽  
Venus Flytrap ◽  
Dionaea Muscipula ◽  
Cell Arrays ◽  
Electrical Signaling

AbstractUpon stimulation, plants elicit electrical signals that can travel within a cellular network analogous to the animal nervous system. It is well-known that in the human brain, voltage changes in certain regions result from concerted electrical activity which, in the form of action potentials (APs), travels within nerve-cell arrays. Electro- and magnetophysiological techniques like electroencephalography, magnetoencephalography, and magnetic resonance imaging are used to record this activity and to diagnose disorders. Here we demonstrate that APs in a multicellular plant system produce measurable magnetic fields. Using atomic optically pumped magnetometers, biomagnetism associated with electrical activity in the carnivorous Venus flytrap, Dionaea muscipula, was recorded. Action potentials were induced by heat stimulation and detected both electrically and magnetically. Furthermore, the thermal properties of ion channels underlying the AP were studied. Beyond proof of principle, our findings pave the way to understanding the molecular basis of biomagnetism in living plants. In the future, magnetometry may be used to study long-distance electrical signaling in a variety of plant species, and to develop noninvasive diagnostics of plant stress and disease.

Action Potential and Contraction of Dionaea muscipula (Venus Flytrap)

Science ◽  
1961 ◽  
Vol 133 (3456) ◽  
pp. 878-879 ◽  
Author(s):  
J. R. Di Palma ◽  
R. Mohl ◽  
W. Best
Keyword(s):  
Action Potential ◽  
Venus Flytrap ◽  
Dionaea Muscipula

Dynamics of amino acid redistribution in the carnivorous Venus flytrap (Dionaea muscipula ) after digestion of 13 C/15 N-labelled prey

Plant Biology ◽  
2017 ◽  
Vol 19 (6) ◽  
pp. 886-895 ◽  
Author(s):  
J. Kruse ◽  
P. Gao ◽  
M. Eibelmeier ◽  
S. Alfarraj ◽  
H. Rennenberg
Keyword(s):  
Amino Acid ◽  
Venus Flytrap ◽  
Dionaea Muscipula

scholarly journals Bacterial Cell Wall Quality Control during Environmental Stress

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Elizabeth A. Mueller ◽  
Petra Anne Levin
Keyword(s):  
Quality Control ◽  
Cell Wall ◽  
Cell Surface ◽  
Environmental Stress ◽  
Environmental Conditions ◽  
Bacterial Cell ◽  
Cell Shape ◽  
Bacterial Cell Wall ◽  
Peptidoglycan Synthesis ◽  
Peptidoglycan Cell Wall

ABSTRACT Single-celled organisms must adapt their physiology to persist and propagate across a wide range of environmental conditions. The growth and division of bacterial cells depend on continuous synthesis of an essential extracellular barrier: the peptidoglycan cell wall, a polysaccharide matrix that counteracts turgor pressure and confers cell shape. Unlike many other essential processes and structures within the bacterial cell, the peptidoglycan cell wall and its synthesis machinery reside at the cell surface and are thus uniquely vulnerable to the physicochemical environment and exogenous threats. In addition to the diversity of stressors endangering cell wall integrity, defects in peptidoglycan metabolism require rapid repair in order to prevent osmotic lysis, which can occur within minutes. Here, we review recent work that illuminates mechanisms that ensure robust peptidoglycan metabolism in response to persistent and acute environmental stress. Advances in our understanding of bacterial cell wall quality control promise to inform the development and use of antimicrobial agents that target the synthesis and remodeling of this essential macromolecule. IMPORTANCE Nearly all bacteria are encased in a peptidoglycan cell wall, an essential polysaccharide structure that protects the cell from osmotic rupture and reinforces cell shape. The integrity of this protective barrier must be maintained across the diversity of environmental conditions wherein bacteria replicate. However, at the cell surface, the cell wall and its synthesis machinery face unique challenges that threaten their integrity. Directly exposed to the extracellular environment, the peptidoglycan synthesis machinery encounters dynamic and extreme physicochemical conditions, which may impair enzymatic activity and critical protein-protein interactions. Biotic and abiotic stressors—including host defenses, cell wall active antibiotics, and predatory bacteria and phage—also jeopardize peptidoglycan integrity by introducing lesions, which must be rapidly repaired to prevent cell lysis. Here, we review recently discovered mechanisms that promote robust peptidoglycan synthesis during environmental and acute stress and highlight the opportunities and challenges for the development of cell wall active therapeutics.

scholarly journals Cardiolipin Alters Rhodobacter sphaeroides Cell Shape by Affecting Peptidoglycan Precursor Biosynthesis

mBio ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ti-Yu Lin ◽  
William S. Gross ◽  
George K. Auer ◽  
Douglas B. Weibel
Keyword(s):  
Cell Wall ◽  
Rhodobacter Sphaeroides ◽  
Cell Morphology ◽  
Cell Shape ◽  
Molecular Mechanisms ◽  
Wild Type ◽  
Anionic Phospholipid ◽  
Content Type ◽  
Lipid Ii ◽  
Topological Features

ABSTRACT Cardiolipin (CL) is an anionic phospholipid that plays an important role in regulating protein biochemistry in bacteria and mitochondria. Deleting the CL synthase gene (Δcls) in Rhodobacter sphaeroides depletes CL and decreases cell length by 20%. Using a chemical biology approach, we found that a CL deficiency does not impair the function of the cell wall elongasome in R. sphaeroides; instead, biosynthesis of the peptidoglycan (PG) precursor lipid II is decreased. Treating R. sphaeroides cells with fosfomycin and d-cycloserine inhibits lipid II biosynthesis and creates phenotypes in cell shape, PG composition, and spatial PG assembly that are strikingly similar to those seen with R. sphaeroides Δcls cells, suggesting that CL deficiency alters the elongation of R. sphaeroides cells by reducing lipid II biosynthesis. We found that MurG—a glycosyltransferase that performs the last step of lipid II biosynthesis—interacts with anionic phospholipids in native (i.e., R. sphaeroides) and artificial membranes. Lipid II production decreases 25% in R. sphaeroides Δcls cells compared to wild-type cells, and overexpression of MurG in R. sphaeroides Δcls cells restores their rod shape, indicating that CL deficiency decreases MurG activity and alters cell shape. The R. sphaeroides Δcls mutant is more sensitive than the wild-type strain to antibiotics targeting PG synthesis, including fosfomycin, d-cycloserine, S-(3,4-dichlorobenzyl)isothiourea (A22), mecillinam, and ampicillin, suggesting that CL biosynthesis may be a potential target for combination chemotherapies that block the bacterial cell wall. IMPORTANCE The phospholipid composition of the cell membrane influences the spatial and temporal biochemistry of cells. We studied molecular mechanisms connecting membrane composition to cell morphology in the model bacterium Rhodobacter sphaeroides. The peptidoglycan (PG) layer of the cell wall is a dominant component of cell mechanical properties; consequently, it has been an important antibiotic target. We found that the anionic phospholipid cardiolipin (CL) plays a role in determination of the shape of R. sphaeroides cells by affecting PG precursor biosynthesis. Removing CL in R. sphaeroides alters cell morphology and increases its sensitivity to antibiotics targeting proteins synthesizing PG. These studies provide a connection to spatial biochemical control in mitochondria, which contain an inner membrane with topological features in common with R. sphaeroides.

scholarly journals Vibrio choleraeadapts to sessile and motile lifestyles by cyclic di-GMP regulation of cell shape

2020 ◽  
Vol 117 (46) ◽  
pp. 29046-29054 ◽  
Author(s):  
Nicolas L. Fernandez ◽  
Brian Y. Hsueh ◽  
Nguyen T. Q. Nhu ◽  
Joshua L. Franklin ◽  
Yann S. Dufour ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Shape ◽  
Guanosine Monophosphate ◽  
Human Pathogen ◽  
Flagellar Motility ◽  
Wild Type ◽  
Gene Encoding ◽  
Regulatory Pathways ◽  
Matrix Components ◽  
Curved Rod

The cell morphology of rod-shaped bacteria is determined by the rigid net of peptidoglycan forming the cell wall. Alterations to the rod shape, such as the curved rod, occur through manipulating the process of cell wall synthesis. The human pathogenVibrio choleraetypically exists as a curved rod, but straight rods have been observed under certain conditions. While this appears to be a regulated process, the regulatory pathways controlling cell shape transitions inV. choleraeand the benefits of switching between rod and curved shape have not been determined. We demonstrate that cell shape inV. choleraeis regulated by the bacterial second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) by posttranscriptionally repressing expression ofcrvA, a gene encoding an intermediate filament-like protein necessary for curvature formation inV. cholerae.This regulation is mediated by the transcriptional cascade that also induces production of biofilm matrix components, indicating that cell shape is coregulated withV. cholerae’s induction of sessility. During microcolony formation, wild-typeV. choleraecells tended to exist as straight rods, while genetically engineering cells to maintain high curvature reduced microcolony formation and biofilm density. Conversely, straightV. choleraemutants have reduced swimming speed when using flagellar motility in liquid. Our results demonstrate regulation of cell shape in bacteria is a mechanism to increase fitness in planktonic and biofilm lifestyles.

Local differentiation of cell wall matrix polysaccharides in sinuous pavement cells: its possible involvement in the flexibility of cell shape

Plant Biology ◽  
2018 ◽  
Vol 20 (2) ◽  
pp. 223-237 ◽  
Author(s):  
P. Sotiriou ◽  
E. Giannoutsou ◽  
E. Panteris ◽  
B. Galatis ◽  
P. Apostolakos
Keyword(s):  
Cell Wall ◽  
Cell Shape ◽  
Pavement Cells ◽  
Local Differentiation ◽  
Cell Wall Matrix

scholarly journals How the carnivorous waterwheel plant ( Aldrovanda vesiculosa ) snaps

2018 ◽  
Vol 285 (1878) ◽  
pp. 20180012 ◽  
Author(s):  
Anna S. Westermeier ◽  
Renate Sachse ◽  
Simon Poppinga ◽  
Philipp Vögele ◽  
Lubomir Adamec ◽  
...  
Keyword(s):  
Computer Simulations ◽  
Compliant Mechanisms ◽  
Venus Flytrap ◽  
Dionaea Muscipula ◽  
Mechanical Modelling ◽  
Biomimetic Approach ◽  
Fast Motion

The fast motion of the snap-traps of the terrestrial Venus flytrap ( Dionaea muscipula ) have been intensively studied, in contrast to the tenfold faster underwater snap-traps of its phylogenetic sister, the waterwheel plant ( Aldrovanda vesiculosa ). Based on biomechanical and functional–morphological analyses and on a reverse biomimetic approach via mechanical modelling and computer simulations, we identify a combination of hydraulic turgor change and the release of prestress stored in the trap as essential for actuation. Our study is the first to identify and analyse in detail the motion principle of Aldrovanda , which not only leads to a deepened understanding of fast plant movements in general, but also contributes to the question of how snap-traps may have evolved and also allows for the development of novel biomimetic compliant mechanisms.

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