Larval Movement Research Articles

Fetal Exposure to the Synthetic‐Progesterone Levonorgestrel (LNG) targets the brain resulting in hyperactive behavior using the Zebrafish (Danio rerio) as a model

Anxiety‐related disorders are a rising health concern in adolescent and young adults. Evidence suggests that disrupting normal neuronal development (neurogenesis) in the fetal brain could play a role in the manifestation of mental health disorders later in life. Growing literature suggests a role in hormone receptor (HR)‐regulated brain development, particularly in the hypothalamus, the neuroendocrine section of the brain and part of the limbic center. Yet, this link has not been thoroughly investigated. Levonorgestrel (LNG), a synthetic steroid used in contraceptive pills in adults, may also pose a threat to the developing brain by targeting HRs. Furthermore, this endocrine disrupting chemical (EDC) has been found at physiologically relevant levels in potable water sources worldwide providing an alternative route of exposure for unknowing individuals. Therefore, we investigated the effects embryonic exposure to LNG had on neurogenesis and hyperactivity using the zebrafish (Danio rerio) as neurobiological model. First, computational modeling using Quantitative structure‐activity relationships (QSAR), determined the predicted bioavailability, physiological half‐life and overall potential efficacy of LNG as a neuroendocrine disruptor. Next, Zebrafish were bred and fertilized embryos were collected and individually placed in 96‐well plates. Embryos were exposed to LNG levels (at doses ranging from 5–1000ng/L) or a vehicle control starting at 3 hours post fertilization (hpf) to 5 days pf (dpf), the time encompassing neurogenesis. There were no observable differences in fertilization ratios, hatching or morphology between LNG treated groups and vehicle controls. On 5 dpf, all treated and controls were assayed for changes in locomotor activity (i.e. hyperactivity busts). Larval movement were analyzed using computational locomotor activity software. Interestingly, the 5ng dose of LNG significantly (p<0.05) increased hyperactive behavior compared to vehicle controls. HR expression and neuronal marker α‐HuC were used to document neurogenesis. Our data suggests that the observed LNG‐induced hyperactivity represents anxiety‐like behavior as a manifestation of aberrant neurogenesis. This is the first study to show that exposure to low environmentally relevant levels of LNG causes hyperactivity and thus, potentially alters HR regulated neuronal development increasing the risk of other mental issues later in life.Support or Funding InformationThis project was supported in part by UTRGV College of Science (COS) Research Enhancement Seed Grants Program to RKD, the UTRGV Presidential Graduate Research Fellowship to AF and GH, the UTRGV COS Dean's Fellowship to EZ, and the UTRGV Engaged Scholars Award to BHS.

LarvaSPA, A Method for Mounting Drosophila Larva for Long-Term Time-Lapse Imaging.

Live imaging is a valuable approach for investigating cell biology questions. The Drosophila larva is particularly suited for in vivo live imaging because the larval body wall and most internal organs are transparent. However, continuous live imaging of intact Drosophila larvae for longer than 30 min has been challenging because it is difficult to noninvasively immobilizeimmobilizing larvae for a long time. Here we present a larval mounting method called LarvaSPA that allows for continuous imaging of live Drosophila larvae with high temporal and spatial resolution for longer than 10 hours. This method involves partially attaching larvae to the coverslip using a UV-reactive glue and additionally restraining larval movement using a polydimethylsiloxane (PDMS) block. This method is compatible with larvae at developmental stages from second instar to wandering third instar. We demonstrate applications of this method in studying dynamic processes of Drosophila somatosensory neurons, including dendrite growth and injury-induced dendrite degeneration. This method can also be applied to study many other cellular processes that happen near the larval body wall.

Movement behaviour of two social urticating caterpillars in opposite hemispheres

BackgroundInvestigating movement ecology of organisms has economic, societal, and conservation benefits. Larval movement of insects for example, plays many significant ecological roles, and with the expansion of the human population and development, encounters and conflicts with insects have increased. Urticating caterpillars are a health concern to people and animals, especially when they disperse in a gregarious and synchronised manner in areas frequented by humans. Ochrogaster lunifer and Thaumetopoea pityocampa from the southern and northern hemispheres respectively, are two geographically-isolated species of moth with similar gregarious urticating caterpillars that can outbreak causing defoliation and medical issues.MethodsEach year from March to May, O. lunifer and T. pityocampa caterpillars leave their nesting sites and form head-to-tail processions on the ground in search of pupation sites. This pre-pupation procession behaviour and its associated risk of human contact with O. lunifer and T. pityocampa caterpillars were studied and compared in Australia and Italy, respectively. The distance, duration, orientation and response to visible light of the pre-pupation processions were studied in both species to determine general patterns.ResultsIn the morning, O. lunifer and T. pityocampa processions travelled on average 40 and 16 m per day from the nest in 153 and 223 min respectively, in search for potential pupation sites. Ochrogaster lunifer pre-pupation processions travelled generally to the north or south when leaving the nest, as was their final orientation to the bivouac/pupation site. Whereas T. pityocampa processions had no preference in orientation. Ochrogaster lunifer and T. pityocampa pre-pupation processions travelled towards the darker and the lighter areas of the environment, respectively. During our observations, 27% of O. lunifer and 44% of T. pityocampa processions had contact with humans driving, cycling or walking.ConclusionsThe amount of human contact is surprising and alarming, because of the serious health implications they cause to humans and animals. The processionary dispersal on the ground risks further spread of urticating hairs that can be easily detached, and particular during inadvertent contact. Our limited sample size of T. pityocampa processions may benefit from more observations to make conclusive remarks on their pre-pupation behaviour. Understanding the movement behaviour of O. lunifer and T. pityocampa pre-pupation processions around populated areas is crucial for predicting exposure risk and application of management strategies.

Impedance Measures and a Mounting Technique for Drosophila: Larval Movements, Heart Rate, Imaging, and Electrophysiology.

Monitoring movements of larval Drosophila with electrical detection allows one to record the behaviors without the use of lights and cameras. This is a suitable technique when studying the use of light-sensitive proteins in optogenetic studies. Electrical measures are feasible to use in determining when a larva starts to move or continues to move after a light induced activation of channelrhodopsin. We have developed a technique using an electrical measure of the media as an index of larval movement. As a proof of concept, recordings with an infrared camera of the larval movement were simultaneous made with electrical measures. The two techniques parallel each other in their ability to index larval movements. Bright light-emitting diode (LED) lights used in optogenetic experiments tend to saturate the detectors of the camera unless filters are used and different filters maybe necessary depending on the LED spectrum and sensitivity of the camera. Impedance measures are independent of the type of LED or brightness. We also assessed the use of a non-solvent based glue (3M Vetbond) to hold larvae in place while measuring synaptic function of neuromuscular junctions, cardiac function and influence of modulators, or activation of light-sensitive channels.

Adjuvant-free immunization with infective filarial larvae as lymphatic homing antigen carriers

Controlled infection with intestinal nematodes has therapeutic potential for preventing the symptoms of allergic and autoimmune diseases. Here, we engineered larvae of the filarial nematode Litomosoides sigmodontis as a vaccine strategy to induce adaptive immunity against a foreign, crosslinked protein, chicken egg ovalbumin (OVA), in the absence of an external adjuvant. The acylation of filarial proteins with fluorescent probes or biotin was not immediately detrimental to larval movement and survival, which died 3 to 5 days later. At least some of the labeled and skin-inoculated filariae migrated through lymphatic vessels to draining lymph nodes. The immunization potential of OVA-biotin-filariae was compared to that of an OVA-bound nanoparticulate carrier co-delivered with a CpG adjuvant in a typical vaccination scheme. Production of IFNγ and TNFα by restimulated CD4+ cells but not CD8+ confirmed the specific ability of filariae to stimulate CD4+ T cells. This alternative method of immunization exploits the intrinsic adjuvancy of the attenuated nematode carrier and has the potential to shift the vaccination immune response towards cellular immunity.

Toxicity comparison of nano-sized and micron-sized microplastics to Goldfish Carassius auratus Larvae

Plastic pollution is one of the most serious environmental issues worldwide. The negative influence of plastics on aquatic organisms has increasingly concerned, especially the influence of microplastic (MPs). In the present study, the toxicology of nano-sized MPs (nMPs) and micron-sized MPs (mMPs) were comparatively studied. Goldfish larvae were exposed to 10, 100 and 1000 μg/L nMPs and mMPs for 1, 3 and 7 days. The enrichment of MPs, body length, heart rate, motor ability, microscopic and ultrastructure of intestine, liver, gill and muscle tissue, as well as the oxidative stress were analyzed. Results showed that both 70 nm and 50 μm MPs were accumulated in the digestive tract of larvae. MPs at high concentrations could induce oxidative stress, destroy intestine, liver and gill tissues, increase heart rate, and inhibit growth and swimming speed of the larvae. The most important finding was that nMPs could enter into the muscle tissue through the epidermis of the larvae. It could cause damage to muscle tissue, destroy nerve fibers, inhibit acetylcholinase (AchE) activity, and show great adverse effects on larval movement than mMPs. In conclusion, both nMPs and mMPs at higher concentrations can cause damage to fish larvae and nMPs are potentially more hazardous.

Estimates of common milkweed (Asclepias syriaca) utilization by monarch larvae (Danaus plexippus) and the significance of larval movement

The population of monarch butterflies east of the Rocky Mountains has noticeably declined over the past two decades. The decline is due, in part, to loss of breeding and forage habitat in the Southern and Midwestern USA. To support a resilient overwintering population of six hectares of occupied forest canopy, approximately 1.6–1.8 billion additional ramets of milkweed are needed in the summer breeding range. Milkweed establishment that facilitates natural behavior of monarchs is necessary for effective conservation restoration. This study explored the effect of milkweed ramet density on larval search behavior, milkweed utilization, and survival without predation, parasitism, or competition. Under our experimental greenhouse conditions, monarch larvae abandoned their natal ramet, and subsequent ramets, prior to the pre-pupal wandering stage and before all available leaf biomass on a ramet was consumed. This is consistent with previous field observations. Larvae consumed biomass from three or four milkweed ramets that totaled the approximate biomass of single 10–35 cm ramet. Movement behavior suggests that isolated ramets may not support development through pupation, even though an isolated ramet could provide enough biomass. Our results suggest milkweed patches containing at least two to four ramets of closely-spaced common milkweed would provide sufficient biomass for development and increase the likelihood that larvae moving in random directions would encounter non-natal ramets to support development. Larval movement behavior and biomass requirements are critical aspects of monarch larval biology that should be considered in habitat restoration and maintenance plans, monitoring survey designs and protocols, and population modeling.

Ethovision detection of larval movements of Spodoptera litura (Fabricius) populations from different regions of Punjab

Ethovision detection of larval movements of <i>Spodoptera litura</i> (Fabricius) populations from different regions of Punjab

DMSO effects larval zebrafish (Danio rerio) behavior, with additive and interaction effects when combined with positive controls

Embryonic and larval zebrafish (Danio rerio) behavior is commonly used to identify neurotoxic compounds. Here, we investigated whether sub-lethal exposures to the common solvents dimethyl sulfoxide (DMSO, 0.01–1%) and methanol (MeOH, 0.01–1%), or the anti-fungal agent methylene blue (MB, 0.0001–0.0005%), can influence larval behavior in a simple light/dark paradigm conducted in 96-well plates. In addition, we tested whether the media volume within the behavioral arena or the zebrafish strain, AB wild type, AB Tübingen (AB/TU), or Tüpfel long-fin (TL), could also influence larval behavior. Following the single exposures, we co-exposed larvae to DMSO and either MB or two other compounds with known behavioral effects in larval zebrafish, flutamide and perfluorooctanesulfonic acid (PFOS). We found ≥0.55% DMSO and 0.0005% MB significantly affected larval behavior, but there was no effect of MeOH. Similarly, TL showed less movement compared to AB and AB/TU strains, whereas lower media volumes also significantly reduced larval movement. However, all strains responded similarly to DMSO and MB. In the co-exposure studies, we found either additive or interaction effects between DMSO and either MB, flutamide, or PFOS, depending on the behavioral endpoint measured. In addition, media volume had no effect on the DMSO concentration response curve, but again we observed additive effects on behavior. In conclusion, methodology can lead to alterations in baseline locomotor activity and compounds can have additive or interaction effects on behavioral endpoints. However, we found no evidence that strain effects should be a concern when deciding on solvents for a simple light/dark behavioral test in larval zebrafish.

Ocean acidification changes the vertical movement of stone crab larvae.

Anthropogenic activities are increasing ocean temperature and decreasing ocean pH. Some coastal habitats are experiencing increases in organic runoff, which when coupled with a loss of vegetated coastline can accelerate reductions in seawater pH. Marine larvae that hatch in coastal habitats may not have the ability to respond to elevated temperature and changes in seawater pH. This study examined the response of Florida stone crab (Menippe mercenaria) larvae to elevated temperature (30°C control and 32°C treatment) and CO2-induced reductions in pH (8.05 pH control and 7.80 pH treatment). We determined whether those singular and simultaneous stressors affect larval vertical movement at two developmental stages. Geotactic responses varied between larval stages. The direction and rate of the vertical displacement of larvae were dependent on pH rather than temperature. Stage III larvae swam upwards under ambient pH conditions, but swam downwards at a faster rate under reduced pH. There was no observable change in the directional movement of Stage V larvae. The reversal in orientation by Stage III larvae may limit larval transport in habitats that experience reduced pH and could pose challenges for the northward dispersal of stone crabs as coastal temperatures warm.

Discriminating Natal Source Populations of a Temperate Marine Fish Using Larval Otolith Chemistry

The life cycles of many marine species depend on a dispersive larval stage that connects spatially segregated populations. However, quantifying larval movement among populations remains one of the greatest challenges in marine ecology. Such movement determines whether a population is essentially a self-recruiting stock, or if it forms part of a larger meta-population where recruits originate from multiple sources. Previous research has struggled to differentiate between such stock structure models for King George whiting (Sillaginodes punctatus; Perciformes) in southern Australia, largely due to difficulties in identifying the source populations of dispersing larvae. In this study, pelagic larvae were collected throughout the only recognized spawning area in South Australia in 2017 and 2018. First, we identified that the distribution of larvae was broadly divisible into two groups – those in southern Spencer Gulf and those in Investigator Strait. Then, the incremental structure and elemental composition of otoliths of larvae from the two regions were compared to determine if they had originated from a common source population. There were no spatial differences in the sizes (3.0-5.0 mm SL), ages (5-21 d), hatch dates (7-24 April) or average growth rates (0.09-0.21 mm d-1) of larvae. However, multi-elemental (Li, Mg, Mn, Sr and Ba) otolith signatures differed significantly between the two regions, primarily driven by differences in concentrations of Li and Ba. Although otolith signatures were year-specific, larvae were assigned to their region of capture with 70-82% accuracy. Larvae in each region hatched at the same time yet had significantly different otolith chemistry, providing strong evidence that those in southern Spencer Gulf and Investigator Strait originated from spatially segregated water masses. This study has demonstrated the ability of otolith chemistry to discriminate source populations of pelagic larvae in a fully marine environment, which provides a basis to quantify larval movement between fish populations.

Heterozygosity fitness correlations and generation interval of the Norway lobster in the Aegean Sea, eastern Mediterranean

BackgroundComprehensively detailed information on population dynamics for benthic species is crucial since potential admixture of individuals could shift the genetic subdivision and age structure during a full breeding period. The apparent genetic impact of the potential recruitment strategy of Norway lobster Nephrops norvegicus is still under research. For this reason the present study was focused on genetic variation of the species over a given continuous year period in a semi-enclosed gulf of the Aegean Sea.ResultsAnalyses revealed that the relative smaller size class in females and the apparent faster growth of males may represent a key-role differential strategy for the two sexes, whereas females tend to mature slower. Heterozygosity fitness correlations (HFCs) showed substantially significant associations suggesting that inbreeding depression for females and outbreeding depression for males are the proximate fitness mechanisms, respectively.ConclusionsNephrops norvegicus uniformal genetic composition (background of high gene flow), could be attributed to potential population recolonization, due to a hypothesized passive larval movement from deeper waters, which may suggest that some offspring of local residents and potential male non-breeders from other regions admixture randomly.

Light Spot-Based Assay for Analysis of Drosophila Larval Phototaxis.

The larvae of Drosophila melanogaster show obvious light-avoiding behavior during the foraging stage. Drosophila larval phototaxis can be used as a model to study animal avoidance behavior. This protocol introduces a light-spot assay to investigate larval phototactic behavior. The experimental set-up includes two main parts: a visual stimulation system that generates the light spot, and an infrared light-based imaging system that records the process of larval light avoidance. This assay allows tracking of the behavior of larva before entering, during encountering, and after leaving the light spot. Details of larval movement including deceleration, pause, head casting, and turning can be captured and analyzed using this method.

Larval Movement of Spotted Wing Drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae)

Laboratory experiments were conducted to determine larval movement of the spotted wing drosophila (Drosophila suzukii Matsumura). Movement of larvae outside of the wild blueberry fruit (Vaccinium angustifolium Aiton) can occur after exhausting fruit food resources pri- or to completion of development or just prior to pupation. We found that when provided a choice larvae select moist compared to dry environments both in plastic arenas providing only filter paper for shelter and in a soil filled petri dishes. Movement was usually limited to less than 7.5 cm in the soil from a release point. An exponential decay model suggests that only 0.1% of a larval population will move as far as 17.5 cm. Results of our study suggest that while larvae move readily, they have minimal ability to avoid localized xeric soil micro-climatic conditions through movement. However, they will select less stressful moist soil environments.

Aristolochiaceae‐ and Asteraceae‐feeding by larvae of Papilio xuthus L. (Lepidoptera: Papilionidae) in Japan: A review

AbstractOur recent observations of Aristolochiaceae‐ and Asteraceae‐feeding by larvae of Papilio xuthus L. (Lepidoptera: Papilionidae), which is generally a typical Rutaceae‐feeding swallowtail, inspired us to survey published works describing its host range and aspects of its chemical ecology. Papilio xuthus larvae have been observed feeding on a total of 22 plant species other than members of Rutaceae, including those of Asarum (Aristolochiaceae) and Cosmos (Asteraceae). Most observation records and our current study indicated that Aristolochiaceae‐feeding by P. xuthus larvae was not due to oviposition error, but to larval movement to Asarum from adjacent rutaceous hosts after they had become unsustaining. Many larvae developed on Asarum to further stadia but we confirmed that some did not, indicating that Asarum was unsuitable for some individuals. According to previous and current observations, P. xuthus females oviposit directly on Cosmos and their larvae can develop to adults although, again, their performance on these plants is not always favorable. Host choice by swallowtail butterflies is determined both at the egg‐laying and larval‐feeding stages. Although adult P. xuthus use a mixture of unique secondary metabolites as their host‐location cue, larvae use primary nutrients as their major phagostimulants. Larval feeding on Asarum could suggest a reversion triggered by vestigial chemosensitivity to ancestral olfactory and/or gustatory cues, because several major clades of Papilionidae feed on Aristolochiaceae. Further studies on the phytochemical/chemosensory bases for these associations are needed if we are to understand the evolutionary pathway of host selection in P. xuthus, as indicated by these relatively unusual host‐seeking behaviors.

How survival and food intake of tri-spine horseshoe crabs, Tachypleus tridentatus respond to thermal variation: implications for understanding its distribution limit

ABSTRACTTemperature appears to have pervasive effects on larval development, feeding and movement patterns of tri-spine horseshoe crabs, Tachypleus tridentatus. To investigate how temperature determines their geographic distribution range, we examined the survival rate (SR), survival time (ST) and food intake of subadult T. tridentatus under different temperature levels in a seven-day experiment, followed by a three-day recovery to room temperature at 25°C. Significantly lower SR and ST of subadults were found at 40°C after the end of the seven-day experiment. Meanwhile, SR and ST of individuals at 0°C were negatively affected when the temperature was brought back to 25°C. Mean food intake of the subadults was statistically lower at 0–20°C and 35–40°C compared to that at 25°C and 30°C. After the subsequent three-day recovery to 25°C, only the individuals previously exposed to 15°C and 20°C had recovered to their normal level of feeding activities, but not the other treatment groups. These findings may provide preliminary data on how thermal tolerance determines the present distribution of T. tridentatus, which are found in large numbers around Beibu Gulf (annual temperature variation: 22–30°C), while considerably lower population densities are observed in the colder southern Sea of Japan and warmer seas of Southeast Asia.

Field Mark-Recapture of Calcein-Stained Larval Oysters (Crassostrea virginica) in a Freshwater-Dominated Estuary

Knowledge of larval transport is important for restoration and management efforts; yet, there are no established methods to determine larval transport in situ. Calcein staining of oyster larvae may help fill this void, and a two-part study was conducted to determine its effectiveness at tracking larval oyster transport in the field. First, it was tested whether oysters could be successfully stained, survive, and grow at estuarine salinities (15, 20, 26), and at sufficiently large numbers (millions of oysters) to support field mark-recapture studies. Second, the field-based application was tested by releasing 22 million stained larvae twice (high and low salinity) into a major estuary, and two methods (fluorescent microscopy and FlowCam) were used to detect recaptured larvae. Results were compared with expected larval movement patterns simulated by an existing larval transport model. Calcein concentrations (100 mg L−1) did not affect larval growth or survival, but handling conditions (water salinity manipulations and tank size) did affect growth and survival during the post-staining period. Microscopy had double the detection capacity, but FlowCam was more practical and time efficient for the large-volume, high particulate load field samples. Larvae (n = 2) were recaptured during the second, higher salinity release, and model comparison showed a 1–2-day time-lag between field recapture and model predictions, suggesting need for model refinement. Calcein has potential to be a useful marker to track larval movement at large scales needed for field-based studies, providing critical information to aid in selection of restoration sites and management of commercially important shellfish species.

External Marking and Behavior of Early Instar Helicoverpa armigera (Lepidoptera: Noctuidae) on Soybean

Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) is a pest of major agricultural crops, such as soybean and cotton. A better understanding of larval movement is important for its integrated management and resistance management. Studies with neonates through second instar larvae are still limited by the difficulties involving the handling and observation of these instars. Many studies require marking larvae, and most research involving marking is focused on moths. However, our study investigated aspects of larval behavior of the second instar of H. armigera on soybean plants. The dyes luminous powder red and Sudan Red 7B were tested as external larval markers. Both dyes successfully marked the larvae for most of 1 stadium (48 h) without deleterious effects, and are useful for short-period behavioral studies. Luminous powder red was selected for the H. armigera larval behavior study on soybean because of ease of detection during both day and night. Second instar on-plant movement was consistent, independent of the d period (morning, afternoon, evening). In general, larvae established their feeding site within a few hours of release, and remained feeding on soybean leaves. Second instar behavior suggests that management by nocturnal insecticide application, based on H. armigera larval movement, would not have an advantage over daytime application.

Direction Selectivity in Drosophila Proprioceptors Requires the Mechanosensory Channel Tmc

Drosophila Transmembrane channel-like (Tmc) is a protein that functions in larval proprioception. The closely related TMC1 protein is required for mammalian hearing and is a pore-forming subunit of the hair cell mechanotransduction channel. In hair cells, TMC1 is gated by small deflections of microvilli thatproduce tension on extracellular tip-links that connect adjacent villi. How Tmc might be gated in larval proprioceptors, which are neurons having a morphology that is completely distinct from hair cells, is unknown. Here, we have used high-speed confocal microscopy both to measure displacements of proprioceptive sensory dendrites during larval movement and to optically measure neural activity of the moving proprioceptors. Unexpectedly, the pattern of dendrite deformation for distinct neurons was unique and differed depending on the direction of locomotion: ddaE neuron dendrites were strongly curved by forward locomotion, while the dendrites of ddaD were more strongly deformed by backward locomotion. Furthermore, GCaMP6f calcium signals recorded in the proprioceptive neurons during locomotion indicated tuning to the direction of movement. ddaE showed strong activation during forward locomotion, while ddaD showed responses that were strongest during backward locomotion. Peripheral proprioceptive neurons in animals mutant for Tmc showed a near-complete loss of movement related calcium signals. As the strength of the responses of wild-type animals was correlated with dendrite curvature, we propose that Tmc channels may be activated by membrane curvature in dendrites that are exposed to strain. Our findings begin to explain how distinct cellular systems rely on a common molecular pathway for mechanosensory responses.

Prostaglandin E2 promotes embryonic vascular development and maturation in zebrafish.

ABSTRACTProstaglandin (PG)-E2 is essential for growth and development of vertebrates. PGE2 binds to G-coupled receptors to regulate embryonic stem cell differentiation and maintains tissue homeostasis. Overproduction of PGE2 by breast tumor cells promotes aggressive breast cancer phenotypes and tumor-associated lymphangiogenesis. In this study, we investigated novel roles of PGE2 in early embryonic vascular development and maturation with the microinjection of PGE2 in fertilized zebrafish (Danio rerio) eggs. We injected Texas Red dextran to trace vascular development. Embryos injected with the solvent of PGE2 served as vehicle. Distinct developmental changes were noted from 28–96 h post fertilization (hpf), showing an increase in embryonic tail flicks, pigmentation, growth, hatching and larval movement post-hatching in the PGE2-injected group compared to the vehicle. We recorded a significant increase in trunk vascular fluorescence and maturation of vascular anatomy, embryo heartbeat and blood vessel formation in the PGE2 injected group. At 96 hpf, all larvae were euthanized to measure vascular marker mRNA expression. We observed a significant increase in the expression of stem cell markers efnb2a, ephb4a, angiogenesis markers vegfa, kdrl, etv2 and lymphangiogenesis marker prox1 in the PGE2-group compared to the vehicle. This study shows the novel roles of PGE2 in promoting embryonic vascular maturation and angiogenesis in zebrafish.This article has an associated First Person interview with the first author of the paper.