scholarly journals Departures from isotropy: the kinematics of a larval snail in response to food

2020 ◽  
pp. jeb.239178
Author(s):  
Michelle H. DiBenedetto ◽  
Kirstin S. Meyer-Kaiser ◽  
Brooke Torjman ◽  
Jeanette D. Wheeler ◽  
Lauren S. Mullineaux
Keyword(s):  
Environmental History ◽  
Environmental Cues ◽  
Foraging Success ◽  
Strong Anisotropy ◽  
Larval Behavior ◽  
Ocean Modelling ◽  
Crepidula Fornicata ◽  
Trade Offs ◽  
Invertebrate Larvae ◽  
Horizontal Layers

The swimming behavior of invertebrate larvae can affect their dispersal, survival, and settlement in the ocean. Modelling this behavior accurately poses unique challenges as behavior is controlled both by physiology and environmental cues. Some larvae use cilia to both swim and create feeding currents, resulting in potential trade-offs between the two functions. Food availability is naturally patchy and often occurs in shallow horizontal layers in the ocean. Also, larval swimming motions generally differ in the horizontal and vertical. In order to investigate behavioral response to food by ciliated larvae, we measure their behavioral anisotropy by quantifying deviations from a model based in isotropic diffusion. We hypothesize that larvae will increase horizontal swimming and decrease vertical swimming after encountering food which could lead to aggregation at food layers. We consider Crepidula fornicata larvae which are specifically of interest as they exhibit unsteady and variable swimming behaviors that are difficult to categorize. We tracked the larvae in still water with and without food, with a portion of the larvae starved beforehand. On average, larvae in the presence of food were observed higher in the water column, with higher swimming speeds and higher horizontal swimming velocities when compared to larvae without food. Starved larvae also exhibited higher vertical velocities in food, suggesting no aggregation behavior. While most treatments showed strong anisotropy in larval behavior, we found that starved larvae without food exhibited approximately isotropic kinematics, indicating that behavioral anisotropy can vary with environmental history and conditions to enhance foraging success or mitigate food-poor environments.

The induction of metamorphosis of marine invertebrate larvae: stimulus and response

1983 ◽  
Vol 61 (8) ◽  
pp. 1701-1719 ◽  
Author(s):  
Robert D. Burke
Keyword(s):  
Direct Evidence ◽  
Marine Invertebrate ◽  
Behavioral Model ◽  
Environmental Cues ◽  
Sensory Receptors ◽  
Response Model ◽  
Endocrine Control ◽  
Stimulus Response ◽  
Invertebrate Larvae ◽  
Induction Of Metamorphosis

The induction of metamorphosis by environmentally derived cues is reviewed in barnacles, molluscs, hydroids, echinoids, and ascidians in the context of the neurological and behavioral model of stimulus and response. The model proposes that cues associated with preferred juvenile or adult habitats are the stimuli. Stimuli are received by receptors that communicate with the effectors of metamorphosis, larval and adult tissues. The response is a combination of morphogenetic, histolytic, and histogenic processes. Receptors in all five taxa are assumed to be superficial sensory receptors, though there is no direct evidence for their involvement in the perception of cues. Although the induction of metamorphosis by environmental cues in all five taxa fits well within a stimulus–response model, there is currently only circumstantial evidence for neural or endocrine control of metamorphosis.

Carryover effects of brooding conditions on larvae in the slipper limpet Crepidula fornicata

2020 ◽  
Vol 643 ◽  
pp. 87-97
Author(s):  
K Meyer-Kaiser
Keyword(s):  
Life Histories ◽  
Marine Invertebrate ◽  
Common Garden ◽  
Carryover Effects ◽  
Larval Biology ◽  
Experimental Conditions ◽  
Larval Size ◽  
Crepidula Fornicata ◽  
Environmental Variations ◽  
Invertebrate Larvae

Larval dispersal is a critical step in the life-histories of sessile benthic invertebrates. There is a growing body of research showing plasticity in marine invertebrate larvae, but the causes and ranges of intraspecific variation in larvae are not completely understood. In this study, field-based collections of Crepidula fornicata larvae in 2017 motivated a laboratory experiment on carryover effects in 2019. Experimental conditions that approximated environmental conditions experienced by mothers in the field were used to test whether seasonal environmental variations during brooding could lead to differences in larval size and the time to develop to competency. Mothers were kept in 2 different temperature and feeding treatments during brooding, but larvae were cultured in a common garden. Larvae that were brooded at spring temperatures (~13°C) took longer to develop to competency in the common garden and grew larger before becoming competent than larvae brooded at warmer summer temperatures (~21°C). There was no effect of maternal feeding (fed or not fed) on time to develop to competency or larval size. Thus, C. fornicata larvae released earlier in the year are likely to spend longer periods in the water column. They may disperse farther and grow to larger size before settlement. C. fornicata is a model species for larval biology. The results of this study can be used to inform biophysical modelling efforts and refine predictions of connectivity or species range shifts in a changing climate.

scholarly journals Non-epigenetic mechanisms enable short memories of the environment for cell cycle commitment

2020 ◽  
Author(s):  
Yimiao Qu ◽  
Jun Jiang ◽  
Xiang Liu ◽  
Xiaojing Yang ◽  
Chao Tang
Keyword(s):  
Cell Cycle ◽  
Yeast Cell ◽  
Environmental History ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Environmental Cues ◽  
Time Duration ◽  
Cell Cycle Inhibitor ◽  
Cell Cycle Entry ◽  
Temporal Profiles

ABSTRACTCells continuously survey their environment in order to make fundamental decisions, including whether to divide, migrate, or differentiate. However, a fascinating phenomenon in biology is that cells often possess memory—they temporally integrate both past and present signals to make a reliable decision. Cellular memory manifests across different biological systems over different timescales, and a variety of underlying molecular mechanisms have been proposed. Here we investigate a non-epigenetic molecular mechanism underpinning how a single yeast cell can remember its recent environmental history to decide whether to enter the cell cycle. This “memories” is encoded by the phosphorylation level of the cell cycle inhibitor Whi5. G1 cyclin Cln3 senses environmental nutrient levels and promotes cell-cycle entry by phosphorylating and thus inactivating Whi5. We developed an optogenetic system whereby the nuclear localization of Cln3 can be rapidly and reversibly controlled by light. By monitoring cellular response to different temporal profiles of Cln3, we found that cell cycle entry requires the time duration of nuclear Cln3, supporting the model of “cellular memories”. Moreover, instead of the memory could last for the entire G1 phase as previously observed in glucose, we found Whi5 re-activates rapidly, with a similar half-time ∼ 12 min, in a variety of nutrient and stress conditions. Our results suggest yeast cell can shortly remember its recent environmental cues to decide whether to enter the cell cycle.

Phenotypic Plasticity of Feeding Structures in Marine Invertebrate Larvae

2018 ◽  
Keyword(s):  
Phenotypic Plasticity ◽  
Molecular Mechanisms ◽  
Sea Urchins ◽  
Marine Invertebrate ◽  
Future Research ◽  
Trade Offs ◽  
Feeding Structure ◽  
Research Findings ◽  
Planktotrophic Larvae ◽  
Invertebrate Larvae

Nearly three decades ago, biologists discovered that planktotrophic larvae of sea urchins can alter the size of their ciliated feeding structures in response to the concentration of food (i.e., unicellular algae). In the years since, this response has become one of the best-studied examples of phenotypic plasticity in marine organisms. Researchers have found that this form of plasticity occurs widely among different types of feeding larvae in several phyla, and involves energetic trade-offs with a suite of correlated life history characters. Furthermore, investigators have recently started to unravel the genetic and molecular mechanisms underlying this plasticity. We review the literature on feeding-structure plasticity in marine invertebrate larvae. We highlight the diversity of species and variety of experimental designs and statistical methodologies, summarize research findings to draw more general conclusions, and target promising directions for future research.

scholarly journals When to stay, when to go: trade-offs for southern African arid-zone birds in times of drought

2009 ◽  
Vol 105 (1/2) ◽  
Author(s):  
W.R.J. Dean ◽  
P. Barnard ◽  
M.D. Anderson
Keyword(s):  
Breeding Success ◽  
Arid Zone ◽  
Punctuated Equilibrium ◽  
Environmental Cues ◽  
Arid Environments ◽  
Aquatic Species ◽  
Punctuated Equilibrium Theory ◽  
Resident Species ◽  
Theory Of Evolution ◽  
Trade Offs

Arid environments remind one of the punctuated equilibrium theory of evolution: they experience long periods of stasis and low productivity, interrupted with episodic rainfall which spurs reproduction and movement. Birds, as highly dispersive organisms, are among the most dramatic indicators of these fluctuations. Here we review birds' two main strategies, residency and nomadism, and the trade-offs faced by individuals in uncertain times. In general, wet years stimulate higher densities of nests (i.e. smaller territories), larger clutch sizes, unseasonal breeding, and at some times of year, higher breeding success. Rainfall above a certain threshold triggers breeding in resident species and an influx of nomadic species which breed and then move on. The environmental cues which trigger nomadism are sometimes poorly understood, but include distant thunderstorms for aquatic species, and perhaps for insectivores. Environmental cues that draw nomadic granivores to areas that have had recent rain are not known.

scholarly journals A microbial perspective on the life-history evolution of marine invertebrate larvae: if, where, and when to feed

2017 ◽  
Author(s):  
Tyler J. Carrier ◽  
Jason Macrander ◽  
Adam M. Reitzel
Keyword(s):  
Life History ◽  
Marine Invertebrate ◽  
Life History Evolution ◽  
Trade Offs ◽  
Pelagic Environment ◽  
History Evolution ◽  
Planktotrophic Larvae ◽  
Invertebrate Larvae ◽  
Microbiome Data ◽  
Feeding Environments

AbstractThe feeding environment for planktotrophic larvae has a major impact on development and progression towards competency for metamorphosis. High phytoplankton environments that promote growth often have a greater microbial load and incidence of pathogenic microbes, while areas with lower food availability have a lower number of potential pathogens. Trade-offs between metabolic processes associated with growth and immune functionality have been described throughout the animal kingdom and may influence the life-history evolution of marine invertebrate planktotrophic larvae in these environments. Namely, to avoid potential incidences of microbial-mediated mortality and/or dysbiosis, larvae should regulate time spent between these two feeding environments. We describe here transcriptomic and microbiome data that supports this trade-off in larvae, where larvae in a well-fed environment upregulate genes associated with metabolism and may regularly enter a state of dysbiosis, resulting in mortality. To address the hypothesis that the environmental microbiota is a selective force on if, where, and when planktotrophic larvae should feed, we present a strategy for determining the specific interactions of larvae and microbes at a scale representative of their larger pelagic environment.

scholarly journals Vibroconvective Patterns in a Layer under Translational Vibrations of Circular Polarization

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 108
Author(s):  
Victor Kozlov ◽  
Kirill Rysin ◽  
Aleksei Vjatkin
Keyword(s):  
Heat Transfer ◽  
Rayleigh Number ◽  
Horizontal Plane ◽  
Velocity Fields ◽  
Strong Anisotropy ◽  
Vibrational Convection ◽  
Piv Method ◽  
Thermovibrational Convection ◽  
Convective Cells ◽  
Horizontal Layers

This article experimentally investigates thermal vibrational convection in horizontal layers, subject to circular translational oscillations in the horizontal plane. The definite direction of translational vibrations lacks investigation, and the case of a layer heated from above is considered. At large negative values of the gravitational Rayleigh number, the thermovibrational convection appears in a threshold manner with an increase in the vibration intensity. Our results show that in the case of strong gravitational stabilization, thermovibrational convection develops in the form of patterns with strong anisotropy of spatial periods in orthogonal directions. The vibroconvective patterns have the form of parallel rolls divided along their length into relatively short segments. The layer thickness determines the distance between the rolls, and the longitudinal wavelength, depends on the Rayleigh number. Convective cells are studied using the noninvasive thermohromic methodic. It is found that when using the tracers for flow visualization, the concentration and type of the visualizer particles have a serious impact on the shape of the observed vibroconvective structures. In particular, the presence of even a small number of tracers (used in the study of velocity fields by the PIV method) generates flows and intensifies the heat transfer below the threshold of thermovibrational convection excitation.

Novel players fine-tune plant trade-offs

2015 ◽  
Vol 58 ◽  
pp. 83-100 ◽  
Author(s):  
Selena Gimenez-Ibanez ◽  
Marta Boter ◽  
Roberto Solano
Keyword(s):  
Ubiquitin Ligase ◽  
Feedback Loop ◽  
Molecular Level ◽  
26S Proteasome ◽  
Signalling Molecules ◽  
Transcriptional Reprogramming ◽  
Trade Offs ◽  
Jaz Proteins ◽  
Regulatory Feedback Loop ◽  
Fine Tune

Jasmonates (JAs) are essential signalling molecules that co-ordinate the plant response to biotic and abiotic challenges, as well as co-ordinating several developmental processes. Huge progress has been made over the last decade in understanding the components and mechanisms that govern JA perception and signalling. The bioactive form of the hormone, (+)-7-iso-jasmonyl-l-isoleucine (JA-Ile), is perceived by the COI1–JAZ co-receptor complex. JASMONATE ZIM DOMAIN (JAZ) proteins also act as direct repressors of transcriptional activators such as MYC2. In the emerging picture of JA-Ile perception and signalling, COI1 operates as an E3 ubiquitin ligase that upon binding of JA-Ile targets JAZ repressors for degradation by the 26S proteasome, thereby derepressing transcription factors such as MYC2, which in turn activate JA-Ile-dependent transcriptional reprogramming. It is noteworthy that MYCs and different spliced variants of the JAZ proteins are involved in a negative regulatory feedback loop, which suggests a model that rapidly turns the transcriptional JA-Ile responses on and off and thereby avoids a detrimental overactivation of the pathway. This chapter highlights the most recent advances in our understanding of JA-Ile signalling, focusing on the latest repertoire of new targets of JAZ proteins to control different sets of JA-Ile-mediated responses, novel mechanisms of negative regulation of JA-Ile signalling, and hormonal cross-talk at the molecular level that ultimately determines plant adaptability and survival.

Sign in / Sign up

Export Citation Format

Share Document