Journal articles: 'Motility behaviour'

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Achikanu, Cosmas, Joao Correia, Héctor A. Guidobaldi, Laura C. Giojalas, Christopher L. R. Barratt, Sarah Martins Da Silva, and Stephen Publicover. "Continuous behavioural ‘switching’ in human spermatozoa and its regulation by Ca2+-mobilising stimuli." Molecular Human Reproduction 25, no. 8 (June 13, 2019): 423–32. http://dx.doi.org/10.1093/molehr/gaz034.

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Abstract Human sperm show a variety of different behaviours (types of motility) that have different functional roles. Previous reports suggest that sperm may reversibly switch between these behaviours. We have recorded and analysed the behaviour of individual human sperm (180 cells in total), each cell monitored continuously for 3–3.5 min either under control conditions or in the presence of Ca2+-mobilising stimuli. Switching between different behaviours was assessed visually (1 s bins using four behaviour categories), and was verified by fractal dimension analysis of sperm head tracks. In the absence of stimuli, ~90% of cells showed at least one behavioural transition (mean rate under control conditions = 6.4 ± 0.8 transitions.min−1). Type 1 behaviour (progressive, activated-like motility) was most common, but the majority of cells (>70%) displayed at least three behaviour types. Treatment of sperm with Ca2+-mobilising agonists had negligible effects on the rate of switching but increased the time spent in type 2 and type 3 (hyperactivation-like) behaviours (P < 2*10−8; chi-square). Treatment with 4-aminopyridine under alkaline conditions (pHo = 8.5), a highly-potent Ca2+-mobilising stimulus, was the most effective in increasing the proportion of type 3 behaviour, biasing switching away from type 1 (P < 0.005) and dramatically extending the duration of type 3 events (P < 10−16). Other stimuli, including 300 nM progesterone and 1% human follicular fluid, had qualitatively similar effects but were less potent. We conclude that human sperm observed in vitro constitutively display a range of behaviours and regulation of motility by [Ca2+]i, at the level of the single cell, is achieved not by causing cells to adopt a ‘new’ behaviour but by changing the relative contributions of those behaviours.

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Grebecki, A. "Cell Behaviour: Control and Mechanisms of Motility." Cell Biology International 24, no. 2 (February 2000): 125. http://dx.doi.org/10.1006/cbir.1999.0470.

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Lai, Sandra, Julien Tremblay, and Eric Déziel. "Swarming motility: a multicellular behaviour conferring antimicrobial resistance." Environmental Microbiology 11, no. 1 (January 2009): 126–36. http://dx.doi.org/10.1111/j.1462-2920.2008.01747.x.

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Torrezan-Nitao, Elis, Héctor Guidobaldi, Laura Giojalas, Christopher Barratt, and Stephen Publicover. "Behavioural switching during oscillations of intracellular Ca2+ concentration in free-swimming human sperm." Reproduction and Fertility 2, no. 1 (March 9, 2021): L5—L7. http://dx.doi.org/10.1530/raf-21-0001.

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Lay summary A human sperm must swim to the egg to fertilise it. To do this the sperm uses different types of swimming (behaviours) as they are needed. When we watch sperm swimming we see that they regularly change behaviour, sometimes repeatedly switching between two different types. Calcium ions inside cells are crucial in controlling many cell functions and in sperm they play a key role in regulating their behaviour. Here we have measured the concentration of calcium ions inside swimming human sperm. We found that in 12/35 (34%) of the cells we assessed, the concentration of calcium changed repeatedly, averaging more than one cycle of rise and fall per minute. These changes in the concentration of calcium ions occurred as the sperm switched swimming stroke, suggesting that oscillation of calcium concentration is involved in controlling the switching of sperm behaviour. Impaired sperm motility is an important cause of subfertility in men. Understanding how sperm behaviour is controlled will allow the development of treatments that can rescue the fertility of sperm with impaired motility.

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Muleev, Egor Yu. "“Travel behaviour”, “Motility”, “Mobility”: revisited the conceptualization of terms." Sociological Journal 21, no. 3 (2015): 8–28. http://dx.doi.org/10.19181/socjour.2015.21.3.2375.

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Browning, Alexander P., Wang Jin, Michael J. Plank, and Matthew J. Simpson. "Identifying density-dependent interactions in collective cell behaviour." Journal of The Royal Society Interface 17, no. 165 (April 2020): 20200143. http://dx.doi.org/10.1098/rsif.2020.0143.

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Scratch assays are routinely used to study collective cell behaviour in vitro . Typical experimental protocols do not vary the initial density of cells, and typical mathematical modelling approaches describe cell motility and proliferation based on assumptions of linear diffusion and logistic growth. Jin et al. (Jin et al . 2016 J. Theor. Biol. 390 , 136–145 ( doi:10.1016/j.jtbi.2015.10.040 )) find that the behaviour of cells in scratch assays is density-dependent, and show that standard modelling approaches cannot simultaneously describe data initiated across a range of initial densities. To address this limitation, we calibrate an individual-based model to scratch assay data across a large range of initial densities. Our model allows proliferation, motility, and a direction bias to depend on interactions between neighbouring cells. By considering a hierarchy of models where we systematically and sequentially remove interactions, we perform model selection analysis to identify the minimum interactions required for the model to simultaneously describe data across all initial densities. The calibrated model is able to match the experimental data across all densities using a single parameter distribution, and captures details about the spatial structure of cells. Our results provide strong evidence to suggest that motility is density-dependent in these experiments. On the other hand, we do not see the effect of crowding on proliferation in these experiments. These results are significant as they are precisely the opposite of the assumptions in standard continuum models, such as the Fisher–Kolmogorov equation and its generalizations.

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Illien, Pierre, Ramin Golestanian, and Ayusman Sen. "‘Fuelled’ motion: phoretic motility and collective behaviour of active colloids." Chemical Society Reviews 46, no. 18 (2017): 5508–18. http://dx.doi.org/10.1039/c7cs00087a.

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Xue, Niannan, Cristina Bertulli, Amine Sadok, and Yan Yan Shery Huang. "Dynamics of filopodium-like protrusion and endothelial cellular motility on one-dimensional extracellular matrix fibrils." Interface Focus 4, no. 2 (April 6, 2014): 20130060. http://dx.doi.org/10.1098/rsfs.2013.0060.

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Endothelial filopodia play key roles in guiding the tubular sprouting during angiogenesis. However, their dynamic morphological characteristics, with the associated implications in cell motility, have been subjected to limited investigations. In this work, the interaction between endothelial cells and extracellular matrix fibrils was recapitulated in vitro , where a specific focus was paid to derive the key morphological parameters to define the dynamics of filopodium-like protrusion during cell motility. Based on one-dimensional gelatin fibrils patterned by near-field electrospinning (NFES), we study the response of endothelial cells (EA.hy926) under normal culture or ROCK inhibition. It is shown that the behaviour of temporal protrusion length versus cell motility can be divided into distinct modes. Persistent migration was found to be one of the modes which permitted cell displacement for over 300 µm at a speed of approximately 1 µm min −1 . ROCK inhibition resulted in abnormally long protrusions and diminished the persistent migration, but dramatically increased the speeds of protrusion extension and retraction. Finally, we also report the breakage of protrusion during cell motility, and examine its phenotypic behaviours.

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van Steijn, Leonie, Inge M. N. Wortel, Clément Sire, Loïc Dupré, Guy Theraulaz, and Roeland M. H. Merks. "Computational modelling of cell motility modes emerging from cell-matrix adhesion dynamics." PLOS Computational Biology 18, no. 2 (February 14, 2022): e1009156. http://dx.doi.org/10.1371/journal.pcbi.1009156.

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Lymphocytes have been described to perform different motility patterns such as Brownian random walks, persistent random walks, and Lévy walks. Depending on the conditions, such as confinement or the distribution of target cells, either Brownian or Lévy walks lead to more efficient interaction with the targets. The diversity of these motility patterns may be explained by an adaptive response to the surrounding extracellular matrix (ECM). Indeed, depending on the ECM composition, lymphocytes either display a floating motility without attaching to the ECM, or sliding and stepping motility with respectively continuous or discontinuous attachment to the ECM, or pivoting behaviour with sustained attachment to the ECM. Moreover, on the long term, lymphocytes either perform a persistent random walk or a Brownian-like movement depending on the ECM composition. How the ECM affects cell motility is still incompletely understood. Here, we integrate essential mechanistic details of the lymphocyte-matrix adhesions and lymphocyte intrinsic cytoskeletal induced cell propulsion into a Cellular Potts model (CPM). We show that the combination of de novo cell-matrix adhesion formation, adhesion growth and shrinkage, adhesion rupture, and feedback of adhesions onto cell propulsion recapitulates multiple lymphocyte behaviours, for different lymphocyte subsets and various substrates. With an increasing attachment area and increased adhesion strength, the cells’ speed and persistence decreases. Additionally, the model predicts random walks with short-term persistent but long-term subdiffusive properties resulting in a pivoting type of motility. For small adhesion areas, the spatial distribution of adhesions emerges as a key factor influencing cell motility. Small adhesions at the front allow for more persistent motility than larger clusters at the back, despite a similar total adhesion area. In conclusion, we present an integrated framework to simulate the effects of ECM proteins on cell-matrix adhesion dynamics. The model reveals a sufficient set of principles explaining the plasticity of lymphocyte motility.

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Fenchel, T. "Motility and chemosensory behaviour of the sulphur bacterium Thiovulum majus." Microbiology 140, no. 11 (November 1, 1994): 3109–16. http://dx.doi.org/10.1099/13500872-140-11-3109.

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Walter, Stefanie, and Klaus Kuschinsky. "Conditioning of nicotine effects on motility and behaviour in rats." Naunyn-Schmiedeberg's Archives of Pharmacology 339-339, no. 1-2 (2004): 208–13. http://dx.doi.org/10.1007/bf00165145.

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Prag, Søren, Eugene A. Lepekhin, Kateryna Kolkova, Rasmus Hartmann-Petersen, Anna Kawa, Peter S. Walmod, Vadym Belman, et al. "NCAM regulates cell motility." Journal of Cell Science 115, no. 2 (January 15, 2002): 283–92. http://dx.doi.org/10.1242/jcs.115.2.283.

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Cell migration is required during development of the nervous system. The regulatory mechanisms for this process, however, are poorly elucidated. We show here that expression of or exposure to the neural cell adhesion molecule (NCAM) strongly affected the motile behaviour of glioma cells independently of homophilic NCAM interactions. Expression of the transmembrane 140 kDa isoform of NCAM (NCAM-140) caused a significant reduction in cellular motility, probably through interference with factors regulating cellular attachment, as NCAM-140-expressing cells exhibited a decreased attachment to a fibronectin substratum compared with NCAM-negative cells. Ectopic expression of the cytoplasmic part of NCAM-140 also inhibited cell motility, presumably via the non-receptor tyrosine kinase p59fyn with which NCAM-140 interacts. Furthermore, we showed that the extracellular part of NCAM acted as a paracrine inhibitor of NCAM-negative cell locomotion through a heterophilic interaction with a cell-surface receptor. As we showed that the two N-terminal immunoglobulin modules of NCAM, which are known to bind to heparin, were responsible for this inhibition, we presume that this receptor is a heparan sulfate proteoglycan. A model for the inhibitory effect of NCAM is proposed, which involves competition between NCAM and extracellular components for the binding to membrane-associated heparan sulfate proteoglycan.

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Sági, László, Rony Swennen, Dirk De Waele, Willy Peumans, Els Van Damme, Annemie Elsen, and Nathalie Wuyts. "Effect of plant lectins on the host-finding behaviour of Radopholus similis." Nematology 5, no. 2 (2003): 205–12. http://dx.doi.org/10.1163/156854103767139699.

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AbstractThe motility and the chemotactic response towards plant roots of Radopholus similis, after treatment with novel types of lectins, were examined in vitro by analysing movement tracks on agar plates. Six plant lectins belonging to five different lectin families and a banana thaumatin-like protein (BanTLP) were included in the experiment. A 1% concentration of Phaseolus vulgaris agglutinin (PHA) had an adverse effect on the motility of R. similis females: 63% showed no or very little movement on agar plates compared to an average of 33% for other lectins and 3% for the control treatment. A 0.05% concentration of PHA still reduced the motility of R. similis females by 75%. Concanavalin A and wheat germ agglutinin did not alter the chemotactic response towards plant roots, despite binding of both lectins to R. similis. In contrast, Galanthus nivalis agglutinin (GNA) reduced orientated movement of R. similis towards plant roots. Subsequently, secretions of R. similis were stained with Coomassie Brilliant Blue R. Nematodes treated with GNA produced secretions less abundantly compared to the control treatment and BanTLP. The other lectins in the experiment had variable effects on secretion.

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Murray, Thomas S., Michel Ledizet, and Barbara I. Kazmierczak. "Swarming motility, secretion of type 3 effectors and biofilm formation phenotypes exhibited within a large cohort of Pseudomonas aeruginosa clinical isolates." Journal of Medical Microbiology 59, no. 5 (May 1, 2010): 511–20. http://dx.doi.org/10.1099/jmm.0.017715-0.

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Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen capable of acutely infecting or persistently colonizing susceptible hosts. P. aeruginosa colonizes surfaces in vitro by either biofilm formation or swarming motility. The choice of behaviour is influenced by the physical properties of the surface and specific nutrient availability, and subject to regulatory networks that also govern type 2 and type 3 protein secretion. Biofilm formation by clinical isolates has been well-studied. However, the swarming behaviour of human isolates has not been extensively analysed. We collected isolates from 237 hospitalized patients without cystic fibrosis and analysed motility and secretion phenotypes of each isolate. We found biofilm formation and swarming to be negatively associated, while swarming was positively associated with the secretion of both proteases and type 3 exoenzymes. Most isolates were capable of type 3 secretion and biofilm formation, even though these traits are considered to favour distinct modes of pathogenesis. Our data demonstrate that while clinical isolates display diverse motility, biofilm and secretion phenotypes, many of the predicted relationships between swarming motility and other phenotypes observed in laboratory strains also hold true for bacteria isolated from human patients.

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Ďuračka, Michal. "The in vitro effect of kanamycin on the behaviour of bovine spermatozoa." Archives of Ecotoxicology 1, no. 4 (December 20, 2019): 36–40. http://dx.doi.org/10.36547/ae.2019.1.4.36-40.

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The use of antibiotics is a common part of animal biotechnologies. Especially, the use of antibiotics in semen extenders is necessary. However, the effect of antibiotics on the spermatozoa structure and function is still not completely examined. Therefore, the aim of our study was to investigate the effect of kanamycin on bovine spermatozoa at concentrations of 80 and 160 µg/mL during the 24 h in vitro cultivation. Semen samples were collected from clinically healthy Holstein-Friesian bulls. At times of 0, 2 and 24 h the motility assessment, mitochondrial activity, acrosomal and membrane integrity evaluation were performed. The sperm motility was measured using the Computer-assisted sperm analysis (CASA). Mitochondrial activity was evaluated through the Mitochondrial Toxicity Test (MTT). The acrosomal status was determined using the fast green/rose bengal staining on slides. Similarly, the membrane integrity was analysed using the eosin-nigrosin staining. Our results revealed the dose- and time-dependent effect of kanamycin under the in vitro conditions. In conclusion, the selected concentrations of kanamycin may have adverse effects on the motility, mitochondrial activity, acrosomal and membrane integrity during semen processing. Considering the relatively low concentrations used, we do not recommend to use kanamycin as a supplement in bovine semen extenders.

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Lowenthal, Andrew C., Christopher Simon, Amber S. Fair, Khalid Mehmood, Karianne Terry, Stephanie Anastasia, and Karen M. Ottemann. "A fixed-time diffusion analysis method determines that the three cheV genes of Helicobacter pylori differentially affect motility." Microbiology 155, no. 4 (April 1, 2009): 1181–91. http://dx.doi.org/10.1099/mic.0.021857-0.

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Helicobacter pylori is a chemotactic bacterium that has three CheV proteins in its predicted chemotaxis signal transduction system. CheV proteins contain both CheW- and response-regulator-like domains. To determine the function of these proteins, we developed a fixed-time diffusion method that would quantify bacterial direction change without needing to define particular behaviours, to deal with the many behaviours that swimming H. pylori exhibit. We then analysed mutants that had each cheV gene deleted individually and found that the behaviour of each mutant differed substantially from wild-type and the other mutants. cheV1 and cheV2 mutants displayed smooth swimming behaviour, consistent with decreased cellular CheY-P, similar to a cheW mutant. In contrast, the cheV3 mutation had the opposite effect and the mutant cells appeared to change direction frequently. Additional analysis showed that the cheV mutants displayed aberrant behaviour as compared to the wild-type in the soft-agar chemotaxis assay. The soft-agar assay phenotype was less extreme compared to that seen in the fixed-time diffusion model, suggesting that the cheV mutants are able to partially compensate for their defects under some conditions. Each cheV mutant furthermore had defects in mouse colonization that ranged from severe to modest, consistent with a role in chemotaxis. These studies thus show that the H. pylori CheV proteins each differently affect swimming behaviour.

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Navarro, Ricard Matas, and Suzanne M. Fielding. "Clustering and phase behaviour of attractive active particles with hydrodynamics." Soft Matter 11, no. 38 (2015): 7525–46. http://dx.doi.org/10.1039/c5sm01061f.

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The level of activity relative to the strength of attraction plays the role of an effective non-equilibrium temperature, counterpart to the thermodynamic temperature in the passive system. Even in the presence of an attractive potential, hydrodynamic interactions strongly suppress motility induced phase separation.

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Zaidi, Mone. "Modularity of osteoclast behaviour and “mode-specific” inhibition of osteoclast function." Bioscience Reports 10, no. 6 (December 1, 1990): 547–56. http://dx.doi.org/10.1007/bf01116615.

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This study is part of an attempt to understand the role of specific cellular activities in the bone resorptive process. Experiments were performed whereby known pharmacological agents were used to inhibit individual modes of osteoclastic activity, such as motility and secretion. The effects of such treatments on bone resorption were assessed by quantitative scanning electron microscopy. The compounds included colchicine, which was used to inhibit osteoclast motility; molybdate ions which were used to selectively inhibit the catalytic activity of secreted acid phosphatase, and omeprazole which was employed to inhibit the secretion of hydrogen ions. All compounds inhibited osteoclastic bone resorption, but singularly affected defined modes of activity. These findings suggest that each mode of osteoclastic activity is essential for the bone resorptive process, and that “mode-specific” inhibition may provide a means whereby excessive activity of the osteoclast can be regulated in disease.

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Juliano, Joseph, Orlando Gil, Andrea Hawkins-Daarud, Sonal Noticewala, Russell C. Rockne, Jill Gallaher, Susan Christine Massey, et al. "Comparative dynamics of microglial and glioma cell motility at the infiltrative margin of brain tumours." Journal of The Royal Society Interface 15, no. 139 (February 2018): 20170582. http://dx.doi.org/10.1098/rsif.2017.0582.

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Microglia are a major cellular component of gliomas, and abundant in the centre of the tumour and at the infiltrative margins. While glioma is a notoriously infiltrative disease, the dynamics of microglia and glioma migratory patterns have not been well characterized. To investigate the migratory behaviour of microglia and glioma cells at the infiltrative edge, we performed two-colour time-lapse fluorescence microscopy of brain slices generated from a platelet-derived growth factor-B (PDGFB)-driven rat model of glioma, in which glioma cells and microglia were each labelled with one of two different fluorescent markers. We used mathematical techniques to analyse glioma cells and microglia motility with both single cell tracking and particle image velocimetry (PIV). Our results show microglia motility is strongly correlated with the presence of glioma, while the correlation of the speeds of glioma cells and microglia was variable and weak. Additionally, we showed that microglia and glioma cells exhibit different types of diffusive migratory behaviour. Microglia movement fit a simple random walk, while glioma cell movement fits a super diffusion pattern. These results show that glioma cells stimulate microglia motility at the infiltrative margins, creating a correlation between the spatial distribution of glioma cells and the pattern of microglia motility.

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Tremblay, Julien, Anne-Pascale Richardson, François Lépine, and Eric Déziel. "Self-produced extracellular stimuli modulate the Pseudomonas aeruginosa swarming motility behaviour." Environmental Microbiology 9, no. 10 (October 2007): 2622–30. http://dx.doi.org/10.1111/j.1462-2920.2007.01396.x.

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Abaurrea Velasco, Clara, Sepehr Dehghani Ghahnaviyeh, Hossein Nejat Pishkenari, Thorsten Auth, and Gerhard Gompper. "Complex self-propelled rings: a minimal model for cell motility." Soft Matter 13, no. 35 (2017): 5865–76. http://dx.doi.org/10.1039/c7sm00439g.

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Particles with internal degrees of collective self-propulsion – modelled as an ensemble of self-propelled rods – show complex motility behaviour, such as random walks, persistent motion, circling, and run-and-circle motion.

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Hanczyc, Martin M. "Metabolism and motility in prebiotic structures." Philosophical Transactions of the Royal Society B: Biological Sciences 366, no. 1580 (October 27, 2011): 2885–93. http://dx.doi.org/10.1098/rstb.2011.0141.

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Easily accessible, primitive chemical structures produced by self-assembly of hydrophobic substances into oil droplets may result in self-moving agents able to sense their environment and move to avoid equilibrium. These structures would constitute very primitive examples of life on the Earth, even more primitive than simple bilayer vesicle structures. A few examples of simple chemical systems are presented that self-organize to produce oil droplets capable of movement, environment remodelling and primitive chemotaxis. These chemical agents are powered by an internal chemical reaction based on the hydrolysis of an oleic anhydride precursor or on the hydrolysis of hydrogen cyanide (HCN) polymer, a plausible prebiotic chemistry. Results are presented on both the behaviour of such droplets and the surface-active properties of HCN polymer products. Such motile agents would be capable of finding resources while escaping equilibrium and sustaining themselves through an internal metabolism, thus providing a working chemical model for a possible origin of life.

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Wuyts, Nathalie, Rony Swennen, and Dirk De Waele. "Effects of plant phenylpropanoid pathway products and selected terpenoids and alkaloids on the behaviour of the plant-parasitic nematodes Radopholus similis, Pratylenchus penetrans and Meloidogyne incognita." Nematology 8, no. 1 (2006): 89–101. http://dx.doi.org/10.1163/156854106776179953.

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AbstractPlants produce a wide range of biologically active chemicals which have been extensively explored for nematode-antagonistic properties. Although phenylpropanoids are part of the chemical defence system of plants against pests and diseases, including parasitic nematodes, no comprehensive study exists which relates (levels of) phenylpropanoid compounds in roots to actual effects on nematode behaviour. Therefore, a broad spectrum evaluation was made of the effects of phenylpropanoids (simple phenolics and flavonoids) and selected monoterpenoids and alkaloids on the behaviour of the migratory endoparasites Radopholus similis and Pratylenchus penetrans and the sedentary endoparasite Meloidogyne incognita. In vitro bioassays assessed effects on chemotaxis, motility, viability and hatch. Compared with the other two nematode species, P. penetrans was remarkably insensitive to the test compounds. Only phloretin was (limited) hatch inhibitive. This property was shared by other chalcone-related compounds for R. similis. Repellents and motility inhibitors for R. similis and M. incognita were found among the simple phenolic compounds. Flavonols stood out as repellent compounds for both these nematode species, while they were, in their degraded form, also motility inhibitors for M. incognita. Dopamine was an attractant for R. similis, while ferulic acid was strongly motility inhibitive and toxic (LC50 of 120 μg ml−1) for this nematode species. Salicylic acid was a strong attractant for M. incognita. The compound was also nematicidal (LC50 of 46 μg ml−1) and an irreversible inhibitor of hatch.

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Brown, A. F., and G. A. Dunn. "Microinterferometry of the movement of dry matter in fibroblasts." Journal of Cell Science 92, no. 3 (March 1, 1989): 379–89. http://dx.doi.org/10.1242/jcs.92.3.379.

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We describe the use of interferometric microscopy coupled with a novel application of Senarmont compensation for detecting and quantifying the distribution of dry matter in cultured cells. In conjunction with video techniques and digital image processing, a two-dimensional, calibrated map of the dry mass distribution in an isolated cell can be obtained and digitally recorded. We have called the technique Digitally Recorded Interferometric Microscopy with Analyser Shift (DRIMAS). The method greatly facilitates the automatic recognition of cells by computer. Recorded time-lapse sequences can be used to establish a database of the growth and motility of specific cells in given experimental conditions. Databases of this type can be analysed to reveal the patterns of growth and locomotory behaviour of individual cells. We describe a systematic method of obtaining parameters of cell size, shape, spreading, intracellular motility and translocation. Auto-correlations and cross-correlations between these parameters can be detected and quantified using time series analysis, revealing potential cause/effect relationships in the mechanisms of growth and motility. Besides characterizing the overall pattern of cell behaviour, these data can also yield information about the instantaneous pattern of intracellular motility. We describe the use of finite element analysis to reveal the dynamics of the intracellular transport of dry matter. This yields the pattern of the minimum flow of dry matter required to account for the changes in its distribution. Most of this flux is not associated with the movement of visible structures and possibly represents the transport of dissociated components of the cytoskeleton. In chick heart fibroblasts, surprisingly high velocities of nearly 2.0 microns s-1 were detected during the period of increased motility following tail detachment. The total kinetic energy associated with the dry mass flux is a single parameter, which characterizes the instantaneous motility of the cell. We found that the kinetic energy of intracellular motility can be several hundred times greater than the kinetic energy of translocation. Kinetic energy may prove to be a very informative single measure of intracellular motility for assessing the effects of malignant transformation, genetic manipulations, and other experimental treatments on the locomotory machinery of the cell.

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Bennett, Rachel R., Calvin K. Lee, Jaime De Anda, Kenneth H. Nealson, Fitnat H. Yildiz, George A. O'Toole, Gerard C. L. Wong, and Ramin Golestanian. "Species-dependent hydrodynamics of flagellum-tethered bacteria in early biofilm development." Journal of The Royal Society Interface 13, no. 115 (February 2016): 20150966. http://dx.doi.org/10.1098/rsif.2015.0966.

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Monotrichous bacteria on surfaces exhibit complex spinning movements. Such spinning motility is often a part of the surface detachment launch sequence of these cells. To understand the impact of spinning motility on bacterial surface interactions, we develop a hydrodynamic model of a surface-bound bacterium, which reproduces behaviours that we observe in Pseudomonas aeruginosa , Shewanella oneidensis and Vibrio cholerae , and provides a detailed dictionary for connecting observed spinning behaviour to bacteria–surface interactions. Our findings indicate that the fraction of the flagellar filament adhered to the surface, the rotation torque of this appendage, the flexibility of the flagellar hook and the shape of the bacterial cell dictate the likelihood that a microbe will detach and the optimum orientation that it should have during detachment. These findings are important for understanding species-specific reversible attachment, the key transition event between the planktonic and biofilm lifestyle for motile, rod-shaped organisms.

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Mills, Kimberley, and Kate Mortimer. "Observations on the tubicolous annelidMagelona alleni(Magelonidae), with discussions on the relationship between morphology and behaviour of European magelonids." Journal of the Marine Biological Association of the United Kingdom 99, no. 4 (October 8, 2018): 715–27. http://dx.doi.org/10.1017/s0025315418000784.

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AbstractFeeding, defecation, palp behaviour and motility of the tubicolous annelid,Magelona alleniwere observed in a laboratory environment. Both surface deposit, and to a lesser extent, suspension feeding were exhibited, with the ingestion of sand grains, and of smaller amounts of foraminiferans and administered commercially available suspension. Predominantly sand could be seen moving through the gut, resulting in conspicuous defecation, not previously observed in other magelonid species. During this ‘sand expulsion’ behaviour, individuals turned around in a network of branched burrows. The posterior was extended from the burrow and substantial amounts of sand were expelled in a string-like formation, involving mucus. The posterior morphology ofM. allenidiffers greatly compared with other European magelonid species, in possessing a large terminal anus, likely related to its diet. In contrast to what has been recorded for other magelonids,M. alleniappears predominately non-selective. The current paper adds credence to the idea that multiple feeding modes exist within the family. Tube-lined burrows were observed to be primarily permanent, and motility of the species reduced in comparison to other magelonids. The differences noted betweenM. alleniand other species is most likely linked to its tubicolous lifestyle. The effect of environmental parameters on observed behaviours is discussed.

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Leigh, T. J., H. A. Bird, I. Hindmarch, and V. Wright. "Measurement of nocturnal body motility: behaviour of osteoarthritic patients and healthy controls." Rheumatology International 8, no. 2 (April 1988): 67–70. http://dx.doi.org/10.1007/bf00271837.

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Nolan, Laura M., Laura C. McCaughey, Jessica Merjane, Lynne Turnbull, and Cynthia B. Whitchurch. "ChpC controls twitching motility-mediated expansion of Pseudomonas aeruginosa biofilms in response to serum albumin, mucin and oligopeptides." Microbiology 166, no. 7 (July 1, 2020): 669–78. http://dx.doi.org/10.1099/mic.0.000911.

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Twitching motility-mediated biofilm expansion occurs via coordinated, multi-cellular collective behaviour to allow bacteria to actively expand across surfaces. Type-IV pili (T4P) are cell-associated virulence factors which mediate twitching motility via rounds of extension, surface attachment and retraction. The Chp chemosensory system is thought to respond to environmental signals to regulate the biogenesis, assembly and twitching motility function of T4P. In other well characterised chemosensory systems, methyl-accepting chemotaxis proteins (MCPs) feed environmental signals through a CheW adapter protein to the histidine kinase CheA to modulate motility. The Pseudomonas aeruginosa Chp system has an MCP PilJ and two CheW adapter proteins, PilI and ChpC, that likely interact with the histidine kinase ChpA to feed environmental signals into the system. In the current study we show that ChpC is involved in the response to host-derived signals serum albumin, mucin and oligopeptides. We demonstrate that these signals stimulate an increase in twitching motility, as well as in levels of 3′−5′-cyclic adenosine monophosphate (cAMP) and surface-assembled T4P. Interestingly, our data shows that changes in cAMP and surface piliation levels are independent of ChpC but that the twitching motility response to these environmental signals requires ChpC. Furthermore, we show that protease activity is required for the twitching motility response of P. aeruginosa to environmental signals. Based upon our data we propose a model whereby ChpC feeds these environmental signals into the Chp system, potentially via PilJ or another MCP, to control twitching motility. PilJ and PilI then modulate T4P surface levels to allow the cell to continue to undergo twitching motility. Our study is the first to link environmental signals to the Chp chemosensory system and refines our understanding of how this system controls twitching motility-mediated biofilm expansion in P. aeruginosa .

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van der Horst, Gerhard, Monique Bennett, and John D. D. Bishop. "CASA in invertebrates." Reproduction, Fertility and Development 30, no. 6 (2018): 907. http://dx.doi.org/10.1071/rd17470.

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Sperm movement has been described in several phyla of invertebrates. Yet, sperm motility has only been quantified using computer-aided sperm analysis (CASA-Mot) in externally fertilising species (broadcast spawners) of two phyla, molluscs and echinoderms. In the present study we quantified in detail the nature of the sperm tracks, percentage motility groupings and detailed kinematics of rapid-, medium- and slow-swimming spermatozoa in the oyster Crassostrea gigas and four species never previously studied by CASA-Mot, namely the molluscs Choromytilus meridionalis, Donax serra and Haliotis midae and the echinoderm Parechinus angulosus. A feature common to all these species are the helical tracks, the diameter of which seems to be species specific. Using CASA-Mot, the behaviour of spermatozoa was also studied over time and in the presence of egg water and Ca2+ modulators such as caffeine and procaine hydrochloride. For the first time, we show that hyperactivation can be induced in all species in the presence of egg water (sea water that was mixed with mature eggs and then centrifuged) and/or caffeine, and these hyperactivated sperm tracks were characterised using CASA-Mot. We relate the different patterns of sperm motility and behaviour to reproductive strategies such as broadcast spawning and spermcasting, and briefly review studies using CASA-Mot on other invertebrates.

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Marchal, M., R. Briandet, S. Koechler, B. Kammerer, and P. N. Bertin. "Effect of arsenite on swimming motility delays surface colonization in Herminiimonas arsenicoxydans." Microbiology 156, no. 8 (August 1, 2010): 2336–42. http://dx.doi.org/10.1099/mic.0.039313-0.

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Herminiimonas arsenicoxydans is a Gram-negative bacterium able to detoxify arsenic-contaminated environments by oxidizing arsenite [As(III)] to arsenate [As(V)] and by scavenging arsenic ions in an extracellular matrix. Its motility and colonization behaviour have been previously suggested to be influenced by arsenite. Using time-course confocal laser scanning microscopy, we investigated its biofilm development in the absence and presence of arsenite. Arsenite was shown to delay biofilm initiation in the wild-type strain; this was partly explained by its toxicity, which caused an increased growth lag time. However, this delayed adhesion step in the presence of arsenite was not observed in either a swimming motility defective fliL mutant or an arsenite oxidase defective aoxB mutant; both strains displayed the wild-type surface properties and growth capacities. We propose that during the biofilm formation process arsenite acts on swimming motility as a result of the arsenite oxidase activity, preventing the switch between planktonic and sessile lifestyles. Our study therefore highlights the existence, under arsenite exposure, of a competition between swimming motility, resulting from arsenite oxidation, and biofilm initiation.

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Reyes, Alvin T., Dave Ambita, Jamie Louise Batalon, Berna Lou Aba, Angelbert Cortes, Cherray Gabrielle Macabecha, and Andrew Montecillo. "Motility and chemotaxis of Escherichia coli in medium with attractant and repellent." Journal of Drug Delivery and Therapeutics 9, no. 5 (September 15, 2019): 15–18. http://dx.doi.org/10.22270/jddt.v9i5.3532.

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This study was conducted in order to satisfy the following objectives: (1) To compare the migration bands of Escherichia coli, Bacillus megaterium and Staphylococcus aureus in Sugar, Indole and Motility (SIM) medium + chemotaxis medium (CM), SIM + attractant (glucose), SIM + repellent (alcohol) and SIM only; (2) To observe and compare the swimming behaviour of E. coli under the microscope in the presence of attractant and repellent; and (3) To compare chemotaxis of E. coli in the presence of attractant and repellent by capillary assay. Motility bands were observed in tubes with SIM + CM, SIM + attractant, SIM + repellent and SIM only that were inoculated with E. coli and B. megaterium. However, the motility band in SIM + repellent travelled less far as compared to SIM + CM and SIM + attractant. No motility bands were observed in tubes inoculated with S. aureus. Highest number of colonies (CFU/mL) were observed in capillary tubes dipped in attractant (3.7 x 108), followed by CM (5.2 x 107) and least in repellent (7.6 x 106). Analysis of data showed that log CFU/mL in capillary tubes dipped in attractant (8.55±0.14) was significantly higher as compared to capillary tubes dipped in CM (7.64±0.29) and repellent (6.87±0.14). Keywords: Escherichia coli, motility, chemotaxis, attractant, repellent

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Netto, I., V. Bostan, L. McCarthy, A. Laursen, K. Gilbride, M. Mehrvar, and R. Pushchak. "Automated image analysis of Euglena gracilis Klebs (Euglenophyta) for measuring sublethal effects of three model contaminants." Water Science and Technology 66, no. 8 (October 1, 2012): 1708–15. http://dx.doi.org/10.2166/wst.2012.387.

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The short-term impacts of atrazine (herbicide), tributyltin (organometal) and copper on the behaviour of Euglena gracilis Klebs (Euglenophyta) were assessed. First, the ECOTOX automated image analysis system was used, which measured swimming velocity, cell shape, percentage of cells swimming upwards, and randomness of swimming. Next, visual observation by microscopy was used to measure percentage of cell motility and cell shape. Behavioural changes can be used as an indicator of stress in less than 24 h, potentially making them suitable for inclusion in early-warning systems for water quality. Findings indicate that E. gracilis is a very sensitive organism to copper, showing inhibition of motility with visual observation at 0.8 μmol/L within 1 h. The image analysis system was in general less sensitive than visual observation for detecting behavioural changes after incubation in copper. In contrast, after exposure to organic contaminants atrazine and tributyltin, the ECOTOX system detected small changes in the number of cells swimming upwards (antigravitactic behaviour) at higher concentrations.

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Sveinsdóttir, Hildur Sóley, Amanda Decker, Christian Christensen, Pablo Botella Lucena, Haraldur Þorsteinsson, Elena Richert, Valerie Helene Maier, Robert Cornell, and Karl Ægir Karlsson. "Motility phenotype in a zebrafish vmat2 mutant." PLOS ONE 17, no. 1 (January 5, 2022): e0259753. http://dx.doi.org/10.1371/journal.pone.0259753.

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In the present study, we characterize a novel zebrafish mutant of solute carrier 18A2 (slc18a2), also known as vesicular monoamine transporter 2 (vmat2), that exhibits a behavioural phenotype partially consistent with human Parkinson´s disease. At six days-post-fertilization, behaviour was analysed and demonstrated that vmat2 homozygous mutant larvae, relative to wild types, show changes in motility in a photomotor assay, altered sleep parameters, and reduced dopamine cell number. Following an abrupt lights-off stimulus mutant larvae initiate larger movements but subsequently inhibit them to a lesser extent in comparison to wild-type larvae. Conversely, during a lights-on period, the mutant larvae are hypomotile. Thigmotaxis, a preference to avoid the centre of a behavioural arena, was increased in homozygotes over heterozygotes and wild types, as was daytime sleep ratio. Furthermore, incubating mutant larvae in pramipexole or L-Dopa partially rescued the motor phenotypes, as did injecting glial cell-derived neurotrophic factor (GDNF) into their brains. This novel vmat2 model represents a tool for high throughput pharmaceutical screens for novel therapeutics, in particular those that increase monoamine transport, and for studies of the function of monoamine transporters.

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Strandkvist, Charlotte, Jeppe Juul, Buzz Baum, Alexandre J. Kabla, and Tom Duke. "A kinetic mechanism for cell sorting based on local variations in cell motility." Interface Focus 4, no. 6 (December 6, 2014): 20140013. http://dx.doi.org/10.1098/rsfs.2014.0013.

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Our current understanding of cell sorting relies on physical difference, either in the interfacial properties or motile force, between cell types. But is such asymmetry a prerequisite for cell sorting? We test this using a minimal model in which the two cell populations are identical with respect to their physical properties and differences in motility arise solely from how cells interact with their surroundings. The model resembles the Schelling model used in social sciences to study segregation phenomena at the scale of societies. Our results demonstrate that segregation can emerge solely from cell motility being a dynamic property that changes in response to the local environment of the cell, but that additional mechanisms are necessary to reproduce the envelopment behaviour observed in vitro . The time course of segregation follows a power law, in agreement with the scaling reported from experiment and in other models of motility-driven segregation.

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Ďuračka, Michal, Marek Halenár, and Eva Tvrdá. "IN VITRO EFECTS OF SELECTED BIOLOGICALLY ACTIVE COMPOUNDS ON RABBIT SPERMATOZOA MOTILITY BEHAVIOUR." Journal of Microbiology, Biotechnology and Food Sciences 6, no. 6 (June 1, 2017): 1290–94. http://dx.doi.org/10.15414/jmbfs.2017.6.6.1290-1294.

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Picchi, S. C., M. A. Takita, H. D. Coletta-Filho, M. A. Machado, and A. A. de Souza. "N-acetylcysteine interferes with the biofilm formation, motility and epiphytic behaviour ofXanthomonas citrisubsp.citri." Plant Pathology 65, no. 4 (August 7, 2015): 561–69. http://dx.doi.org/10.1111/ppa.12430.

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37

Shapiro, Bennett M., and Robert M. Tombes. "A biochemical pathway for a cellular behaviour: pHi, phosphorylcreatine shuttles, and sperm motility." BioEssays 3, no. 3 (September 1985): 100–103. http://dx.doi.org/10.1002/bies.950030303.

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Fenchel, Tom, and Roland Thar. "âCandidatus Ovobacter propellensâ: a large conspicuous prokaryote with an unusual motility behaviour." FEMS Microbiology Ecology 48, no. 2 (May 2004): 231–38. http://dx.doi.org/10.1016/j.femsec.2004.01.013.

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39

Morin, Charles D., and Eric Déziel. "Use of Alternative Gelling Agents Reveals the Role of Rhamnolipids in Pseudomonas aeruginosa Surface Motility." Biomolecules 11, no. 10 (October 6, 2021): 1468. http://dx.doi.org/10.3390/biom11101468.

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Pseudomonas aeruginosa is a motile bacterium able to exhibit a social surface behaviour known as swarming motility. Swarming requires the polar flagellum of P. aeruginosa as well as the secretion of wetting agents to ease the spread across the surface. However, our knowledge on swarming is limited to observed phenotypes on agar-solidified media. To study the surface behaviour and the impact of wetting agents of P. aeruginosa on other surfaces, we assessed surface motility capabilities of the prototypical strain PA14 on semi-solid media solidified with alternative gelling agents, gellan gum and carrageenan. We found that, on these alternative surfaces, the characteristic dendritic spreading pattern of P. aeruginosa is drastically altered. One striking feature is the loss of dependence on rhamnolipids to spread effectively on plates solidified with these alternative gelling agents. Indeed, a rhlA-null mutant unable to produce its wetting agents still spreads effectively, albeit in a circular shape on both the gellan gum- and carrageenan-based media. Our data indicate that rhamnolipids do not have such a crucial role in achieving surface colonization of non-agar plates, suggesting a strong dependence on the physical properties of the tested surface. The use of alternative gelling agent provides new means to reveal unknown features of bacterial surface behaviour.

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Zhang, Guanming, Romain Mueller, Amin Doostmohammadi, and Julia M. Yeomans. "Active inter-cellular forces in collective cell motility." Journal of The Royal Society Interface 17, no. 169 (August 2020): 20200312. http://dx.doi.org/10.1098/rsif.2020.0312.

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The collective behaviour of confluent cell sheets is strongly influenced both by polar forces, arising through cytoskeletal propulsion, and by active inter-cellular forces, which are mediated by interactions across cell-cell junctions. We use a phase-field model to explore the interplay between these two contributions and compare the dynamics of a cell sheet when the polarity of the cells aligns to (i) their main axis of elongation, (ii) their velocity and (iii) when the polarity direction executes a persistent random walk. In all three cases, we observe a sharp transition from a jammed state (where cell rearrangements are strongly suppressed) to a liquid state (where the cells can move freely relative to each other) when either the polar or the inter-cellular forces are increased. In addition, for case (ii) only, we observe an additional dynamical state, flocking (solid or liquid), where the majority of the cells move in the same direction. The flocking state is seen for strong polar forces, but is destroyed as the strength of the inter-cellular activity is increased.

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Andries, L., C. Vanroelen, J. Van Hoof, and L. Vakaet. "Inhibition of cell spreading on the band of extracellular fibres in early chick and quail embryos." Journal of Cell Science 74, no. 1 (March 1, 1985): 37–50. http://dx.doi.org/10.1242/jcs.74.1.37.

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The ventral surface of the upper layer shows a band of extracellular fibrils around the anterior and lateral border of the area pellucida during gastrulation of the chick embryo. Using scanning electron microscopy, we found that this disposition is correlated with the motility of the middle-layer cells of gastrulating chick and quail embryos. Outside the fibrous band, single middle-layer cells and a sheet of mesoblast cells were spread out and possessed lamellae. Single cells on the fibrous band did not form lamellae. The same cell behaviour was obtained with the explants of deep layer on the fibrous band. The fibrous band is assumed to operate as a barrier that inhibits cell motility during gastrulation.

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Maya-Hoyos, Milena, John Leguizamón, Leonardo Mariño-Ramírez, and Carlos Y. Soto. "Sliding Motility, Biofilm Formation, and Glycopeptidolipid Production inMycobacterium colombienseStrains." BioMed Research International 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/419549.

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Mycobacterium colombienseis a novel member of theMycobacterium aviumcomplex, which produces respiratory and disseminated infections in immunosuppressed patients. Currently, the morphological and genetic bases underlying the phenotypic features ofM. colombiensestrains remain unknown. In the present study, we demonstrated thatM. colombiensestrains displaying smooth morphology show increased biofilm formation on hydrophobic surfaces and sliding on motility plates. Thin-layer chromatography experiments showed thatM. colombiensestrains displaying smooth colonies produce large amounts of glycolipids with a chromatographic behaviour similar to that of the glycopeptidolipids (GPLs) ofM. avium. Conversely, we observed a natural rough variant ofM. colombiense(57B strain) lacking pigmentation and exhibiting impaired sliding, biofilm formation, and GPL production. Bioinformatics analyses revealed a gene cluster that is likely involved in GPL biosynthesis inM. colombienseCECT 3035. RT-qPCR experiments showed that motile culture conditions activate the transcription of genes possibly involved in key enzymatic activities of GPL biosynthesis.

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43

Miclea, Vasile, Ilona Gyorgy, Ileana Miclea, Marius Zahan, Alexandru Nagy, and Aurel Potra. "Ejaculate quality is influenced by boar behaviour at the time of collection." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Animal Science and Biotechnologies 73, no. 2 (November 28, 2016): 240. http://dx.doi.org/10.15835/buasvmcn-asb:12208.

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Ejaculates were collected from the same boars twice a week, in spring during two years. Most animals had very good sexual reflexes and were scored as 5. They gave ejaculates which had good volume, concentration and motility and could be processed into the largest number of insemination doses. This had an obvious positive economic effect. Age influenced ejaculate quality in young boars, with the exception of a few animals in which sexual reflexes were diminished. Nevertheless, ejaculates had the necessary characteristics and could be processed.

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44

Turley, E. A., P. Bowman, and M. A. Kytryk. "Effects of hyaluronate and hyaluronate binding proteins on cell motile and contact behaviour." Journal of Cell Science 78, no. 1 (October 1, 1985): 133–45. http://dx.doi.org/10.1242/jcs.78.1.133.

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The effects of hyaluronate on the morphology, motile and social behaviour of embryonic chick heart fibroblasts were examined in the presence or absence of hyaluronate binding proteins (HABP). HABP were inserted onto fibroblasts after treating cells with 0.2 M-urea. Such treatment increased the binding of [125I]HABP to cell monolayers: at saturation, binding was increased threefold compared to untreated monolayers. Generally, the distribution of added HABP was similar to that of endogenous HABP as detected by immunochemistry. [3H]hyaluronate bound to HABP-treated monolayers in amounts that were proportional to the amount of HABP added. HABP alone reduced cell motility, decreased cell underlapping (measured as a nuclear overlap ratio) and promoted cell spreading. Hyaluronate added by itself had no significant effect on cell behaviour. However, in the presence of HABP, hyaluronate increased cell motility, reduced cell spreading, promoted the appearance of surface blebbing and ruffles, and significantly increased the nuclear overlap ratio. These biological effects were proportional to the amounts of hyaluronate and HABP that bound to heart fibroblasts. Fibronectin, bovine serum albumin or sulphated glycosaminoglycans added together with HABP did not mimic the effects of hyaluronate and had little effect additional to HABP alone. The role of HABP as a putative cell binding molecule for hyaluronate and the relationship of hyaluronate to cell social and motile behaviour are discussed in the light of these findings.

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Prasad, Abhinav, Anna Huefner, Sumeet Mahajan, and Ashwin A. Seshia. "Investigating biomechanical noise in neuroblastoma cells using the quartz crystal microbalance." Journal of The Royal Society Interface 12, no. 106 (May 2015): 20141389. http://dx.doi.org/10.1098/rsif.2014.1389.

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Quantifying cellular behaviour by motility and morphology changes is increasingly important in formulating an understanding of fundamental physiological phenomena and cellular mechanisms of disease. However, cells are complex biological units, which often respond to external environmental factors by manifesting subtle responses that may be difficult to interpret using conventional biophysical measurements. This paper describes the adaptation of the quartz crystal microbalance (QCM) to monitor neuroblastoma cells undergoing environmental stress wherein the frequency stability of the device can be correlated to changes in cellular state. By employing time domain analysis of the resulting frequency fluctuations, it is possible to study the variations in cellular motility and distinguish between different cell states induced by applied external heat stress. The changes in the frequency fluctuation data are correlated to phenotypical physical response recorded using optical microscopy under identical conditions of environmental stress. This technique, by probing the associated biomechanical noise, paves the way for its use in monitoring cell activity, and intrinsic motility and morphology changes, as well as the modulation resulting from the action of drugs, toxins and environmental stress.

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VERMEIRE, J. J., J. E. HUMPHRIES, and T. P. YOSHINO. "Signal transduction in larval trematodes: putative systems associated with regulating larval motility and behaviour." Parasitology 131, S1 (March 29, 2006): S57. http://dx.doi.org/10.1017/s0031182005008358.

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Baker, Richard M., Megan E. Brasch, M. Lisa Manning, and James H. Henderson. "Automated, contour-based tracking and analysis of cell behaviour over long time scales in environments of varying complexity and cell density." Journal of The Royal Society Interface 11, no. 97 (August 6, 2014): 20140386. http://dx.doi.org/10.1098/rsif.2014.0386.

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Understanding single and collective cell motility in model environments is foundational to many current research efforts in biology and bioengineering. To elucidate subtle differences in cell behaviour despite cell-to-cell variability, we introduce an algorithm for tracking large numbers of cells for long time periods and present a set of physics-based metrics that quantify differences in cell trajectories. Our algorithm, termed automated contour-based tracking for in vitro environments (ACT IV E), was designed for adherent cell populations subject to nuclear staining or transfection. ACT IV E is distinct from existing tracking software because it accommodates both variability in image intensity and multi-cell interactions, such as divisions and occlusions. When applied to low-contrast images from live-cell experiments, ACT IV E reduced error in analysing cell occlusion events by as much as 43% compared with a benchmark-tracking program while simultaneously tracking cell divisions and resulting daughter–daughter cell relationships. The large dataset generated by ACT IV E allowed us to develop metrics that capture subtle differences between cell trajectories on different substrates. We present cell motility data for thousands of cells studied at varying densities on shape-memory-polymer-based nanotopographies and identify several quantitative differences, including an unanticipated difference between two ‘control’ substrates. We expect that ACT IV E will be immediately useful to researchers who require accurate, long-time-scale motility data for many cells.

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Lokesh, G., Geetha N. Murthy, Veeranna Gowda, Alok Sahay, and Gargi Gargi. "Conservation of wild silkworm genetic resources through cryopreservation: Standardization of sperm processing." Journal of Applied and Natural Science 10, no. 2 (June 1, 2018): 544–47. http://dx.doi.org/10.31018/jans.v10i2.1733.

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Conservation of the invaluable sericigenous genetic resources is of prime importance with respect to their utilization and improvement for wider exploitation. Conservation of wild silkworms and its applicability in hybridization have limitations due to incompatibility, less amenability, change of behaviour under ex situ conditions, non-synchronization of moth eclosion and difficulties in mating between variables. In view of this, the newer technologies such as cryopreservation and artificial insemination are offering better strategies for preservation of biologically active samples like semen at sub-zero temperature (-196º C) conditions for longer duration. In this context, under standardization of sperms preservation from wild silkworms, two methods of semen collection were scrutinized for obtaining active and viable sperm for cryopreservation and further artificial insemination. Semen collection from the seminal vesicle of freshly emerged male moth and the other from the bursa copulatrix (BC) and spermatheca of the female moth after mating. The sperms in the semen collected from seminal vesicle are in the form of bundles known as eupyrene sperm bundles and apyrene sperms. The morphology and behaviour of these sperm bundles were recorded through microscopic examination. To study the density and motility behaviour of the sperms, sperm bundles were treated with proteolytic enzyme (~2-3µg/ml) to digest the membrane and release the sperms. The density and motility behaviour of sperms in the semen recovered from the BC and spermatheca of female moth after mating were higher compared to those released after digestion of sperm bundles from seminal vesicle of the male moth.

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Vázquez, Diego E., and Walter M. Farina. "Locomotion and searching behaviour in the honey bee larva depend on nursing interaction." Apidologie 52, no. 6 (December 2021): 1368–86. http://dx.doi.org/10.1007/s13592-021-00907-0.

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AbstractAlthough honey bee brood does not need to seek shelter or food and restricts its movements to small wax cells, larvae have some degree of motility. Previously, other studies described how honey bee larvae showed analogous behaviours to the wandering period in holometabolous insects. The current research aimed to measure locomotion of the honey bee brood at different conditions of food supply and larval stadia. Besides, we developed an actometry assay to describe the larval behaviour under laboratory conditions. Our results suggested that the satiety and developmental program of larvae modulated their locomotion. Before they pupated, larval speed increased sharply and then it dropped until quiescence. However, starvation also induced an increase in angular velocity of brood. Starved larvae were between three and five times faster than the satiated ones. Moreover, fifth instars left their wax cells after 2 h of starvation without nurse bees. In the actometry assay, larvae showed behaviours of dispersion and changes in their kinematic parameters after detecting a tactile stimulus like the edge of arenas.

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McKinney, R. A. "Physiological roles of spine motility: development, plasticity and disorders." Biochemical Society Transactions 33, no. 6 (October 26, 2005): 1299–302. http://dx.doi.org/10.1042/bst0331299.

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The vast majority of excitatory connections in the hippocampus are made on dendritic spines. Both dendritic spines and molecules within the membrane are able to move, but the physiological role of these movements is unclear. In the developing brain, spines show highly dynamic behaviour thought to facilitate new synaptic connections. Dynamic movements also occur in adults but the role of this movement is unclear. We have studied the effects of the most important excitatory neurotransmitter, glutamat, and found receptor activation to enhance movement of molecules within the spine membrane. This action of glutamate may be important in regulating the trafficking of neurotransmitter receptors that mediate change in synaptic function. In addition, we have studied the dynamic interactions between pre- and postsynaptic structures labelled with FM 4-64 and a membrane-targeted GFP (green fluorescent protein), respectively, in hippocampal slice cultures under conditions of increased activity, such as epilepsy. Our findings suggest a novel form of activity-dependent synaptic plasticity where spontaneous glutamate release is sufficient to trigger changes in the hippocampal microcircuitry by attracting neighbouring spines responsive to an enhanced level of extracellular glutamate.

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Journal articles on the topic 'Motility behaviour'

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