Adaptability in Swimming Pattern: How Do Swimmers Modify Propulsive Action as a Function of Speed?

The effects of the male antifertility agent ornidazole on glycolysis as a prerequisite for fertilization were investigated in rats. Antifertility doses of ornidazole inhibited glycolysis within mature spermatozoa as determined from the lack of glucose utilization, reduced acidosis under anaerobic conditions and reduced glycolytic enzyme activity. As a consequence, cauda epididymidal spermatozoa from ornidazole-fed rats were unable to fertilize rat oocytes in vitro, with or without cumulus cells, which was not due to transfer of an inhibitor in epididymal fluid with the spermatozoa. Under IVF conditions, binding to the zona pellucida was reduced in spermatozoa from ornidazole-fed males and the spermatozoa did not undergo a change in swimming pattern, which was observed in controls. The block to fertilization could be explained by the disruption of glycolysis-dependent events, since reduced binding to the zona pellucida and a lack of kinematic changes were demonstrated by control spermatozoa in glucose-free media in the presence of respiratory substrates. The importance of glycolysis for binding to, and penetration of, the zona pellucida, and hyperactivation in rats is discussed in relation to the glycolytic production of ATP in the principal piece in which local deprivation of energy may explain the reduced force of spermatozoa from ornidazole-fed males.

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Elevated carbon dioxide alters the plasma composition and behaviour of a shark

Biology Letters ◽

10.1098/rsbl.2014.0538 ◽

2014 ◽

Vol 10 (9) ◽

pp. 20140538 ◽

Cited By ~ 59

Author(s):

Leon Green ◽

Fredrik Jutfelt

Keyword(s):

Ocean Acidification ◽

Fossil Fuels ◽

Resting Metabolic Rate ◽

Blood Chemistry ◽

Teleost Fishes ◽

Behavioural Effects ◽

Swimming Pattern ◽

Acclimation Period ◽

Elevated Water ◽

Elasmobranch Fishes

Increased carbon emissions from fossil fuels are increasing the p CO 2 of the ocean surface waters in a process called ocean acidification. Elevated water p CO 2 can induce physiological and behavioural effects in teleost fishes, although there appear to be large differences in sensitivity between species. There is currently no information available on the possible responses to future ocean acidification in elasmobranch fishes. We exposed small-spotted catsharks ( Scyliorhinus canicula ) to either control conditions or a year 2100 scenario of 990 μatm p CO 2 for four weeks. We did not detect treatment effects on growth, resting metabolic rate, aerobic scope, skin denticle ultrastructure or skin denticle morphology. However, we found that the elevated p CO 2 group buffered internal acidosis via accumulation with an associated increase in Na + , indicating that the blood chemistry remained altered despite the long acclimation period. The elevated p CO 2 group also exhibited a shift in their nocturnal swimming pattern from a pattern of many starts and stops to more continuous swimming. Although CO 2 -exposed teleost fishes can display reduced behavioural asymmetry (lateralization), the CO 2 -exposed sharks showed increased lateralization. These behavioural effects may suggest that elasmobranch neurophysiology is affected by CO 2 , as in some teleosts, or that the sharks detect CO 2 as a constant stressor, which leads to altered behaviour. The potential direct effects of ocean acidification should henceforth be considered when assessing future anthropogenic effects on sharks.

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Swimming of the Trophont Zooid of Vorticella Convallaria

10.1115/fedsm2021-63265 ◽

2021 ◽

Author(s):

Dilziba Kizghin ◽

Sangjin Ryu ◽

Younggil Park ◽

Sunghwan Jung

Keyword(s):

Mean Square Displacement ◽

Swimming Velocity ◽

Mean Square ◽

Ciliated Protozoan ◽

Swimming Motility ◽

Swimming Motion ◽

Swimming Pattern ◽

Freshwater Habitats ◽

Gap Height ◽

Swimming Trajectories

Abstract Vorticella convallaria is a ciliated protozoan found in freshwater habitats. In the sessile or stalked trophont form, V. convallaria is shaped somewhat like a balloon as it has a body or zooid (the head of the balloon) that is about 40 μm large with cilia around its oral part, and a stalk (the string of a balloon) anchoring the zooid to a solid surface. When a trophont zooid of V. convallaria detached from the stalk, the zooid swims around in water by creating water flow using its oral cilia. In contrast to the stalk contraction of V. convallaria that has been well studied, the swimming motility of V. convallaria is little known. In this study, we measured the swimming trajectories of the stalkless trophont zooid of V. convallaria using video microscopy and Hele-Shaw cells with a gap height of 25 μm, traced the swimming zooid using image processing, and analyzed the swimming motion in terms of swimming velocity and mean square displacement. The stalkless trophont zooid of V . convallaria was found to swim in circular patterns with intermittent ballistic motions in the confinement, and the average swimming speed ranged from 20 μm/s to 110 μm/s. Since the swimming pattern of V. convallaria appeared to be affected by the level of confinement, we will continue characterizing the ciliate’s swimming in the Hele-Shaw cell with different gap heights. Our study is expected to reveal the swimming motility of V. convallaria and to advance general understanding of swimming of microorganisms.

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Upstream rheotaxis of catalytic Janus spheres

10.26434/chemrxiv-2021-9s6wz ◽

2021 ◽

Author(s):

Priyanka Sharan ◽

Zuyao Xiao ◽

Viviana Mancuso ◽

William E. Uspal ◽

Juliane Simmchen

Keyword(s):

Fluid Flow ◽

Type System ◽

Shear Plane ◽

High Flow ◽

Physical Factors ◽

Theoretical Studies ◽

Directional Response ◽

Swimming Pattern ◽

Flow Speeds ◽

Stream Migration

Fluid flow is ubiquitous in many environments that form habitats for microorganisms. The tendency of organisms to navigate towards or away from flow is termed rheotaxis. Therefore, it is not surprising that both biological and artificial microswimmers show responses to flows that are determined by the interplay of chemical and physical factors. In particular, to deepen understanding of how different systems respond to flows, it is crucial to comprehend the influence played by swimming pattern. In recent studies, pusher-type Janus particles exhibited cross-stream migration in externally applied flows. Earlier, theoretical studies predicted a positive rheotactic response for puller-type spherical Janus micromotors. To compare to a different swimmer, we introduce Cu@SiO2 micromotors that swim towards their catalytic cap. Based on experimental observations, and supported by flow field calculations using a model for self-electrophoresis, we hypothesize that they behave effectively as a puller-type system. We investigate the effect of externally imposed flow on these spherically symmetrical Cu@SiO2 active Janus colloids, and we indeedobserve a steady upstream directional response. Through a simple squirmer model for a puller, we recover the major experimental observations. Additionally, the model predicts a unique “jumping” behaviour for puller-type micro- motors at high flow speeds. Performing additional experiments at high flow speeds, we capture this phenomenon, in which the particles “roll” with their swimming axes aligned to the shear plane, in addition to being dragged down- stream by the fluid flow.

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Influence of Chemotaxis and Swimming Patterns on the Virulence of the Coral PathogenVibrio coralliilyticus

Journal of Bacteriology ◽

10.1128/jb.00791-17 ◽

2018 ◽

Vol 200 (15) ◽

Cited By ~ 6

Author(s):

Blake Ushijima ◽

Claudia C. Häse

Keyword(s):

Type Strain ◽

Wild Type Strain ◽

Bacterial Colonization ◽

Valuable Insight ◽

Wild Type ◽

Coral Mucus ◽

Content Type ◽

Swimming Pattern ◽

Vibrio Coralliilyticus ◽

Insight Into

ABSTRACTChemotaxis, the directed movement toward or away from a chemical signal, can be essential to bacterial pathogens for locating hosts or avoiding hostile environments. The coral pathogenVibrio coralliilyticuschemotaxes toward coral mucus; however, chemotaxis has not been experimentally demonstrated to be important for virulence. To further examine this, in-frame mutations were constructed in genes predicted to be important forV. coralliilyticuschemotaxis. MostVibriogenomes contain multiple homologs of various chemotaxis-related genes, and two paralogs of each forcheB,cheR, andcheAwere identified. Based on single mutant analyses, the paralogscheB2,cheR2, andcheA1were essential for chemotaxis in laboratory assays. As predicted, the ΔcheA1and ΔcheR2strains had a smooth-swimming pattern, while the ΔcheB2strain displayed a zigzag pattern when observed under light microscopy. However, these mutants, unlike the parent strain, were unable to chemotax toward the known attractants coral mucus, dimethylsulfoniopropionate, andN-acetyl-d-glucosamine. The ΔcheB2strain and an aflagellate ΔfliG1strain were avirulent to coral, while the ΔcheA1and ΔcheR2strains were hypervirulent (90 to 100% infection within 14 h on average) compared to the wild-type strain (66% infection within 36 h on average). Additionally, the ΔcheA1and ΔcheR2strains appeared to better colonize coral fragments than the wild-type strain. These results suggest that although chemotaxis may be involved with infection (the ΔcheB2strain was avirulent), a smooth-swimming phenotype is important for bacterial colonization and infection. This study provides valuable insight into understandingV. coralliilyticuspathogenesis and how this pathogen may be transmitted between hosts.IMPORTANCECorals are responsible for creating the immense structures that are essential to reef ecosystems; unfortunately, pathogens like the bacteriumVibrio coralliilyticuscan cause fatal infections of reef-building coral species. However, compared to related human pathogens, the mechanisms by whichV. coralliilyticusinitiates infections and locates new coral hosts are poorly understood. This study investigated the effects of chemotaxis, the directional swimming in response to chemical signals, and bacterial swimming patterns on infection of the coralMontipora capitata. Infection experiments with different mutant strains suggested that a smooth-swimming pattern resulted in hypervirulence. These results demonstrate that the role of chemotaxis in coral infection may not be as straightforward as previously hypothesized and provide valuable insight intoV. coralliilyticuspathogenesis.

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Flow Field Inside and Around a Square Fish Cage Considering Fish School Swimming Pattern

10.1115/omae2021-63047 ◽

2021 ◽

Author(s):

Shuchuang Dong ◽

Sang-gyu Park ◽

Jinxin Zhou ◽

Qiao Li ◽

Takero Yoshida ◽

...

Keyword(s):

Flow Field ◽

Drag Force ◽

Current Speed ◽

Swimming Behavior ◽

School Structure ◽

Fish Swimming ◽

Farmed Fish ◽

Fish Schools ◽

Fish School ◽

Swimming Pattern

Abstract The interaction between fluid and fish cage with stocked fish is extremely complex, including fluid and structure, as well as fluid and fish swimming behavior. The on-current swimming pattern of fish schools was found toward the incoming flow in the previous laboratory studies, which is different from the circular swimming pattern commonly observed in the farming site. In this study, a pseudo fish school structure model (PFS) was proposed to reproduce the five circular swimming patterns of farmed yellowtail, and to investigate the influence of fish school behaviors on the flow field inside and around a model square fish cage in laboratory experiments. The results showed that the drag force acting on the square fish cage increased with the increase of the current speed for all fish school swimming patterns, but no clear difference was observed between the fish school swimming behavior patterns. Overall, the drag force of the square fish cage considering the farmed fish behavior decreased by 11.8%, compared to the drag force of the fish cage without PFS. The current speeds inside and downstream of the fish cage increased almost linearly with increasing current velocities. Compared with the case of the fish cage without PFS, the current speed inside the cage under motionless closely PFS (C0), revolving closely PFS (CR), motionless loosely PFS (L0) and revolving loosely PFS (LR) conditions changed by 10.8%, 9.4%, 65.8% and 39.7%, respectively. In addition, compared to the case of the fish cage without PFS, the current speeds under C0, CR, L0 and LR conditions decreased by 89.8%, 16.3%, 58.2%, and 31.9%, respectively, at 16.0cm downstream from the fish cage, and decreased by 69.2%, 19.4%, 62.7% and 26.3%, respectively, at 63.6cm downstream from the fish cage. Furthermore, the current speed distribution and relative horizontal turbulence intensity distribution inside and around the fish cage under different fish school swimming pattern was discussed. In the future, we will use live fish to conduct experiments to evaluate fish school models.

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Numerical Simulation on the Effects of Fish’s Body Thickness and Swimming Pattern on its Swimming Performance

The Proceedings of the Fluids engineering conference ◽

10.1299/jsmefed.2020.os10-05 ◽

2020 ◽

Vol 2020 (0) ◽

pp. OS10-05

Author(s):

Shuhei YOSHIDA ◽

Tomohiro FUKUI ◽

Koji MORINISHI

Keyword(s):

Numerical Simulation ◽

Swimming Performance ◽

Swimming Pattern

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The central nervous origin of the swimming motor pattern in embryos of Xenopus laevis

Journal of Experimental Biology ◽

10.1242/jeb.99.1.185 ◽

1982 ◽

Vol 99 (1) ◽

pp. 185-196 ◽

Cited By ~ 3

Author(s):

J. A. Kahn ◽

A. Roberts

Keyword(s):

Motor Activity ◽

Similar Pattern ◽

Sensory Feedback ◽

Motor Nerve ◽

Motor Pattern ◽

Cycle Period ◽

Phase Lag ◽

Nerve Activity ◽

Rhythmic Motor ◽

Swimming Pattern

Rhythmic motor nerve activity was recorded in stage 37/38 Xenopus embryos paralysed with curare. The activity was similar to the swimming motor pattern in the following ways: cycle period (40–125 ms), alternation of activity on either side of a segment, rostro-caudal phase lag. Episodes of rhythmic motor activity could be evoked by stimuli that evoke swimming and inhibited by stimuli that normally inhibit swimming. On this basis we conclude that the swimming motor pattern is generated by a central nervous mechanism and is not dependent on sensory feedback. In addition to the swimming pattern, another pattern of motor activity (‘synchrony’) was sometimes recorded in curarized embryos. In this, the rhythmic bursts on either side of a segment occurred in synchrony, and the rhythm period (20–50 ms) was half that in swimming. This was probably not an artifact of curarization as there were indications of a similar pattern in uncurarized embryos. Its function remains unclear.

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Effects of Gonadotropin-Releasing Hormone (GnRH) and Its Analogues on the Physiological Behaviors and Hormone Content of Tetrahymena pyriformis

International Journal of Molecular Sciences ◽

10.3390/ijms20225711 ◽

2019 ◽

Vol 20 (22) ◽

pp. 5711

Author(s):

Eszter Lajkó ◽

Éva Pállinger ◽

Zsombor Kovács ◽

Ildikó Szabó ◽

László Kőhidai

Keyword(s):

Hormone Receptors ◽

Tetrahymena Pyriformis ◽

Gonadotropin Releasing Hormone ◽

Dependent Manner ◽

Releasing Hormone ◽

Hormone Content ◽

Endogenous Histamine ◽

Swimming Pattern ◽

Recognition Ability ◽

Cell Counter

The unicellular Tetrahymena distinguishes structure-related vertebrate hormones by its chemosensory reactions. In the present work, the selectivity of hormone receptors was evaluated by analyzing the effects of various gonadotropin-releasing hormone (GnRH) analogs (GnRH-I, GnRH-III) as well as truncated (Ac-SHDWKPG-NH2) and dimer derivatives ([GnRH-III(C)]2 and [GnRH-III(CGFLG)]2) of GnRH-III on (i) locomotory behaviors, (ii) cell proliferation, and (iii) intracellular hormone contents of Tetrahymena pyriformis. The migration, intracellular hormone content, and proliferation of Tetrahymena were investigated by microscope-assisted tracking analysis, flow cytometry, and a CASY TT cell counter, respectively. Depending on the length of linker sequence between the two GnRH-III monomers, the GnRH-III dimers had the opposite effect on Tetrahymena migration. [GnRH-III(CGFLG)]2 dimer had a slow, serpentine-like movement, while [GnRH-III(C)]2 dimer had a rather linear swimming pattern. All GnRH-III derivatives significantly induced cell growth after 6 h incubation. Endogenous histamine content was uniformly enhanced by Ac-SHDWKPG-NH2 and GnRH-III dimers, while some differences between the hormonal activities of GnRHs were manifested in their effects on intracellular levels of serotonin and endorphin. The GnRH peptides could directly affect Tetrahymena migration and proliferation in a structure-dependent manner, and they could indirectly regulate these reactions by paracrine/autocrine mechanisms. Present results support the theory that recognition ability and selectivity of mammalian hormone receptors can be deduced from a phylogenetically ancient level like the unicellular Tetrahymena.

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Experiments on the central pattern generator for swimming in amphibian embryos

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1982.0004 ◽

1982 ◽

Vol 296 (1081) ◽

pp. 229-243 ◽

Cited By ~ 84

Keyword(s):

Spinal Cord ◽

Central Nervous System ◽

Nervous System ◽

Pattern Generator ◽

Pattern Generation ◽

Motor Output ◽

Cycle Period ◽

Sensory Stimuli ◽

Swimming Pattern ◽

Left And Right

The central nervous system of paralysed Xenopus laevis embryos can generate a motor output pattern suitable for swimming locomotion. By recording motor root activity in paralysed embryos with transected nervous systems we have shown that: (a) the spinal cord is capable of swimming pattern generation; (b) swimming pattern generator capability in the hindbrain and spinal cord is distributed; (c) caudal hindbrain is necessary for sustained swimming output after discrete stimulation. By recording similarly from embryos whose central nervous system was divided longitudinally into left and right sides, we have shown that: (a) each side can generate rhythmic motor output with cycle periods like those in swimming; (b) during this activity cycle period increases within an episode, and there is the usual rostrocaudal delay found in swimming; (c) this activity is influenced by sensory stimuli in the same way as swimming activity; ( d) normal phase coupling of the left and right sides can be established by the ventral commissure in the spinal cord. We conclude that interactions between the antagonistic (left and right) motor systems are not necessary for swimming rhythm generation and present a model for swimming pattern generation where autonomous rhythm generators on each side of the nervous system drive the motoneurons. Alternation is achieved by reciprocal inhibition, and activity is initiated and maintained by tonic excitation from the hindbrain.

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