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Computers in Biology and Medicine Sep 2021As a typical multicellular model organism, the zebrafish has been increasingly used in biological research. Despite the efforts to develop automated zebrafish larva...
As a typical multicellular model organism, the zebrafish has been increasingly used in biological research. Despite the efforts to develop automated zebrafish larva imaging systems, existing ones are still defective in terms of reliability and automation. This paper presents an improved zebrafish larva high-throughput imaging system, which makes improvements to the existing designs in the following aspects. Firstly, a single larva extraction strategy is developed to make larva loading more reliable. The aggregated larvae are identified, classified by their numbers and patterns, and separated by the aspiration pipette or water stream. Secondly, the dynamic model of larva motion in the capillary is established and an adaptive robust controller is designed for decelerating the fast-moving larva to ensure the survival rate. Thirdly, rotating the larva to the desired orientation is automated by developing an algorithm to estimate the larva's initial rotation angle. For validating the improved larva imaging system, a real-time heart rate monitoring experiment is conducted as an application example. Experimental results demonstrate that the goals of the improvements have been achieved. With these improvements, the improved zebrafish larva imaging system remarkably reduces human intervention and increases the efficiency and success/survival rates of larva imaging.
Topics: Algorithms; Animals; Automation; Humans; Larva; Reproducibility of Results; Zebrafish
PubMed: 34352455
DOI: 10.1016/j.compbiomed.2021.104702 -
The International Journal of... 2014Nemerteans, a phylum of marine lophotrochozoan worms, have a biphasic life history with benthic adults and planktonic larvae. Nemertean larval development is... (Review)
Review
Nemerteans, a phylum of marine lophotrochozoan worms, have a biphasic life history with benthic adults and planktonic larvae. Nemertean larval development is traditionally categorized into direct and indirect. Indirect development via a long-lived planktotrophic pilidium larva is thought to have evolved in one clade of nemerteans, the Pilidiophora, from an ancestor with a uniformly ciliated planuliform larva. Planuliform larvae in a member of a basal nemertean group, the Palaeonemertea, have been previously shown to possess a vestigial prototroch, homologous to the primary larval ciliated band in the trochophores of other spiralian phyla, such as annelids and mollusks. We review literature on nemertean larval development, and include our own unpublished observations. We highlight recent discoveries of numerous pilidiophoran species with lecithotrophic larvae. Some of these larvae superficially resemble uniformly ciliated planuliform larvae of other nemerteans. Others possess one or two transverse ciliary bands, which superficially resemble the prototroch and telotroch of some spiralian trochophores. We also summarize accumulating evidence for planktotrophic feeding by larvae of the order Hoplonemertea, which until now were considered to be lecithotrophic. We suggest that 1) non-feeding pilidiophoran larval forms are derived from a feeding pilidium; 2) such forms have likely evolved many times independently within the Pilidiophora; 3) any resemblance of such larvae to the trochophores of other spiralians is a result of convergence and that 4) the possibility of planktotrophy in hoplonemertean larvae may influence estimates of pelagic larval duration, dispersal, and population connectivity in this group.
Topics: Animals; Biological Evolution; Eating; Invertebrates; Larva
PubMed: 25690972
DOI: 10.1387/ijdb.140090sm -
Zootaxa May 2023The mature larva of the Larainae riffle beetle genus Hypsilara Maier & Spangler, 2011 is described here for the first time, based on larvae of Hypsilara autanai...
The mature larva of the Larainae riffle beetle genus Hypsilara Maier & Spangler, 2011 is described here for the first time, based on larvae of Hypsilara autanai Laššová, Čiampor Jr, Čiamporová-Zaťovičová, 2014. The larvae were collected with adults in the stream near the tepui Cerro Autana and Cerro Cuao (southwestern Venezuela) and associated together using DNA barcoding. Larvae of Hypsilara strongly resemble those of Phanoceroides, here we present important morphological diagnostic characters. This description complements the descriptions of the Larainae larvae in the Neotropics, as the larva of Hypsilara was the last one of the group missing so far.
Topics: Animals; Coleoptera; Larva
PubMed: 37518454
DOI: 10.11646/zootaxa.5296.1.8 -
Scientific Reports Feb 2023Individuals of many animal populations exhibit idiosyncratic behaviors. One measure of idiosyncratic behavior is a behavior syndrome, defined as the stability of one or...
Individuals of many animal populations exhibit idiosyncratic behaviors. One measure of idiosyncratic behavior is a behavior syndrome, defined as the stability of one or more behavior traits in an individual across different situations. While behavior syndromes have been described in various animal systems, their properties and the circuit mechanisms that generate them are poorly understood. We thus have an incomplete understanding of how circuit properties influence animal behavior. Here, we characterize olfactory behavior syndromes in the Drosophila larva. We show that larvae exhibit idiosyncrasies in their olfactory behavior over short time scales. They are influenced by the larva's satiety state and odor environment. Additionally, we identified a group of antennal lobe local neurons that influence the larva's idiosyncratic behavior. These findings reveal previously unsuspected influences on idiosyncratic behavior. They further affirm the idea that idiosyncrasies are not simply statistical phenomena but manifestations of neural mechanisms. In light of these findings, we discuss more broadly the importance of idiosyncrasies to animal survival and how they might be studied.
Topics: Animals; Drosophila; Larva; Neurons; Odorants; Behavior, Animal; Syndrome; Drosophila melanogaster; Olfactory Pathways; Drosophila Proteins; Olfactory Receptor Neurons
PubMed: 36765192
DOI: 10.1038/s41598-023-29523-x -
Frontiers in Neural Circuits 2021In the presence of moving visual stimuli, the majority of animals follow the Fourier motion energy (luminance), independently of other stimulus features (edges,...
In the presence of moving visual stimuli, the majority of animals follow the Fourier motion energy (luminance), independently of other stimulus features (edges, contrast, etc.). While the behavioral response to Fourier motion has been studied in the past, how Fourier motion is represented and processed by sensory brain areas remains elusive. Here, we investigated how visual moving stimuli with or without the first Fourier component (square-wave signal or missing fundamental signal) are represented in the main visual regions of the zebrafish brain. First, we monitored the larva's optokinetic response (OKR) induced by square-wave and missing fundamental signals. Then, we used two-photon microscopy and GCaMP6f zebrafish larvae to monitor neuronal circuit dynamics in the optic tectum and the pretectum. We observed that both the optic tectum and the pretectum circuits responded to the square-wave gratings. However, only the pretectum responded specifically to the direction of the missing-fundamental signal. In addition, a group of neurons in the pretectum responded to the direction of the behavioral output (OKR), independently of the type of stimulus presented. Our results suggest that the optic tectum responds to the different features of the stimulus (e.g., contrast, spatial frequency, direction, etc.), but does not respond to the direction of motion if the motion information is not coherent (e.g., the luminance and the edges and contrast in the missing-fundamental signal). On the other hand, the pretectum mainly responds to the motion of the stimulus based on the Fourier energy.
Topics: Animals; Larva; Motion Perception; Neurons; Photic Stimulation; Pretectal Region; Superior Colliculi; Zebrafish
PubMed: 35069128
DOI: 10.3389/fncir.2021.814128 -
Anais Da Academia Brasileira de Ciencias 2019The beautifully colored damselflies included in Neoneura Selys are divided in 28 species known from North, Central and South America. Larval stage is little known, only...
The beautifully colored damselflies included in Neoneura Selys are divided in 28 species known from North, Central and South America. Larval stage is little known, only seven species were described at this stage. We describe and illustrate the final instar larva of Neoneura confundens for the first time. Adults associated to this larva correspond to the blue form of the species and are also discussed and illustrated. The larva of N. confundens is similar to other Neoneura larvae, showing 1 premental seta and a well-marked nodus in caudal lamellae, but it can be differentiated by having fringed posterior margin in all tibiae and in middle and hind tarsi, among other characters. A key to known larvae of Neoneura and new records extending the species range in the southern cone are provided.
Topics: Animals; Body Size; Female; Larva; Male; Odonata; South America; Tibia
PubMed: 31664309
DOI: 10.1590/0001-3765201920190302 -
The Journal of Experimental Biology Jan 2018Most larvae of bony fish are able to swim almost immediately after hatching. Their locomotory system supports several vital functions: fish larvae make fast manoeuvres... (Review)
Review
Most larvae of bony fish are able to swim almost immediately after hatching. Their locomotory system supports several vital functions: fish larvae make fast manoeuvres to escape from predators, aim accurately during suction feeding and may migrate towards suitable future habitats. Owing to their small size and low swimming speed, larval fish operate in the intermediate hydrodynamic regime, which connects the viscous and inertial flow regimes. They experience relatively strong viscous effects at low swimming speeds, and relatively strong inertial effects at their highest speeds. As the larvae grow and increase swimming speed, a shift occurs towards the inertial flow regime. To compensate for size-related limitations on swimming speed, fish larvae exploit high tail beat frequencies at their highest speeds, made possible by their low body inertia and fast neuromuscular system. The shifts in flow regime and body inertia lead to changing functional demands on the locomotory system during larval growth. To reach the reproductive adult stage, the developing larvae need to adjust to and perform the functions necessary for survival. Just after hatching, many fish larvae rely on yolk and need to develop their feeding systems before the yolk is exhausted. Furthermore, the larvae need to develop and continuously adjust their sensory, neural and muscular systems to catch prey and avoid predation. This Review discusses the hydrodynamics of swimming in the intermediate flow regime, the changing functional demands on the locomotory system of the growing and developing larval fish, and the solutions that have evolved to accommodate these demands.
Topics: Animals; Biomechanical Phenomena; Fishes; Larva; Swimming
PubMed: 29326114
DOI: 10.1242/jeb.149583 -
Scientific Reports Mar 2021The larvacean Oikopleura dioica is a planktonic chordate and an emerging model organism with a short life cycle of 5 days that belongs toTunicata (Urochordata), the...
The larvacean Oikopleura dioica is a planktonic chordate and an emerging model organism with a short life cycle of 5 days that belongs toTunicata (Urochordata), the sister clade of vertebrates. It is characterized by the rapid development of a tadpole-shaped body. Organ formation in the trunk proceeds within 7 h after the hatching of the tailbud larvae at 3 h after fertilization (hpf) and is completed at 10 hpf, giving rise to fully functional juveniles as miniature adult form. Serial block face scanning electron microscopy was used to acquire ~ 2000 serial transverse section images of a 3 hpf larva and a 10 hpf juvenile to characterize the structures and cellular composition of the trunk and organs using 3D images and movies. Germ cells were found to fuse and establish a central syncytial cell in the gonad as early as 10 hpf. Larval development gave rise to functional organs after several rounds of cell division through trunk morphogenesis. The feature would make O. dioica ideal for analyzing cellular behaviors during morphogenetic processes using live imaging. The detailed descriptions of the larvae and juveniles provided in this study can be utilized as the start and end points of organ morphogenesis in this rapidly developing organism.
Topics: Animals; Imaging, Three-Dimensional; Larva; Urochordata
PubMed: 33649401
DOI: 10.1038/s41598-021-83706-y -
Methods in Molecular Biology (Clifton,... 2019Zebrafish (Danio rerio) larvae are a uniquely powerful model system which investigate the effects of toxicant exposure on liver development and function. Manufacturing...
Zebrafish (Danio rerio) larvae are a uniquely powerful model system which investigate the effects of toxicant exposure on liver development and function. Manufacturing processes and development of new synthetic compounds increased rapidly since the middle of the twentieth century, resulting in widespread exposure to environmental toxicants. This is compounded by the shift in the global burden of disease from infectious agents to chronic disease, particularly in industrialized nations, which increases the need to investigate the long-term and transgenerational effects of environmental exposures on human health. Zebrafish provide an excellent model to investigate the mechanisms of action of environmental pollutants given their large-scale embryo production and rapid development, which allow for short-term assessment of toxicity in a whole animal system. Here we describe methods for the use of zebrafish to study hepatotoxicity and liver disease induced by chemical toxicants. Many of the genetic, molecular, and cellular processes are conserved between zebrafish and mammals, enabling translation to human populations and diseases.
Topics: Animals; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Environmental Exposure; Gene Expression Profiling; Gene Expression Regulation, Developmental; Larva; Sequence Analysis, RNA; Zebrafish
PubMed: 31069672
DOI: 10.1007/978-1-4939-9182-2_9 -
Integrative and Comparative Biology Nov 2017We review the visual systems of crustacean larvae, concentrating on the compound eyes of decapod and stomatopod larvae as well as the functional and behavioral aspects... (Review)
Review
We review the visual systems of crustacean larvae, concentrating on the compound eyes of decapod and stomatopod larvae as well as the functional and behavioral aspects of their vision. Larval compound eyes of these macrurans are all built on fundamentally the same optical plan, the transparent apposition eye, which is eminently suitable for modification into the abundantly diverse optical systems of the adults. Many of these eyes contain a layer of reflective structures overlying the retina that produces a counterilluminating eyeshine, so they are unique in being camouflaged both by their transparency and by their reflection of light spectrally similar to background light to conceal the opaque retina. Besides the pair of compound eyes, at least some crustacean larvae have a non-imaging photoreceptor system based on a naupliar eye and possibly other frontal eyes. Larval compound-eye photoreceptors send axons to a large and well-developed optic lobe consisting of a series of neuropils that are similar to those of adult crustaceans and insects, implying sophisticated analysis of visual stimuli. The visual system fosters a number of advanced and flexible behaviors that permit crustacean larvae to survive extended periods in the plankton and allows them to reach acceptable adult habitats, within which to metamorphose.
Topics: Animals; Crustacea; Decapoda; Larva; Vision, Ocular; Visual Perception; Zooplankton
PubMed: 29155966
DOI: 10.1093/icb/icx007