Zebrafish最新文献

The transcription factor oligodendrocyte transcription factor 2 (Olig2) plays a central role in specifying motor neurons and oligodendrocytes during vertebrate neural development. While transgenic reporter lines such as TgBAC(olig2:EGFP) have been instrumental in visualizing olig2 expression, they fall short in directly reporting endogenous protein levels and may not fully recapitulate native gene regulation. To address these limitations, we generated a TgKI(olig2-mNeonGreen) zebrafish line using CRISPR/Cas9-mediated knock-in at the endogenous olig2 locus. The resulting Olig2-mNeonGreen fusion protein localizes specifically to the nucleus, enabling direct live imaging and accurate quantification of Olig2-expressing cells. We confirmed that the knock-in preserves endogenous mRNA expression and protein function, and that homozygous fish develop normally. As proof of concept, modulation of Sonic Hedgehog signaling altered Olig2-mNeonGreen+ cell numbers as expected, confirming the reporter's responsiveness to known upstream inputs. This TgKI(olig2-mNeonGreen) line offers a robust tool for studying neural progenitor dynamics in vivo.

In zebrafish housing systems with water recirculation, a daily renewal of at least 10% of the total water volume is generally recommended to preserve optimal water quality. Such aquatic housing systems often rely on reverse osmosis (RO) water. RO production uses large amounts of running water, a high proportion of which is then discharged into waste. A key parameter for water quality control is nitrate, the final transformation product of the nitrogen cycle in water. Here, we used this parameter to test whether daily water renewal could be reduced in our zebrafish housing system without impact on water quality. For 18 months, divided into four periods, we progressively reduced the rate of water renewal from 10% to 6%. We show that nitrate levels are not impacted when renewal rates remain above 8%, making it possible to significantly save on water in zebrafish breeding systems.

Zebrafish (Danio rerio) is recognized as a versatile model for hematopoietic studies due to its transparency, genetic similarity to humans, and ease of manipulation. This study describes a protocol for the ex vivo extraction and differentiation of macrophages from the renal medulla of zebrafish using transgenic lines and L929 cell-conditioned medium (LCCM) as an alternative to recombinant M-CSF. Adult TgMpegmCherry zebrafish were maintained under controlled conditions. Following euthanasia, renal medullary cells were isolated, treated with antibiotics, and cultured in either LCCM or recombinant human M-CSF. Macrophage differentiation was assessed using confocal microscopy (mCherry), flow cytometry, and functional phagocytosis assays. The protocol enabled efficient differentiation of progenitor cells into macrophages, with an average of 49.1% mCherry+ cells after 7 days in LCCM, outperforming recombinant M-CSF. Differentiated cells demonstrated strong phagocytic activity, confirming macrophage functionality. This method provides an accessible approach to obtaining ex vivo zebrafish-derived macrophages, enabling immunological and hematopoietic studies and allowing for functional comparisons with traditional murine macrophage protocols.

The 2024 "Zebrafish in Education and Outreach Workshop" was held at the 18th International Zebrafish Conference (IZFC) in Kyoto, Japan, on August 19th. It was organized by Jennifer O. Liang of the University of Minnesota Duluth (Duluth, MN, US), with formal presentations by Jennifer Liang and Jason Meyers of Colgate University (Hamilton, NY, US), and discussion by all attendees.

Environmental enrichment for research animals does not only promote animal welfare but is also essential for obtaining scientifically relevant and reproducible results. Currently, all available "enrichments" for zebrafish aquaria are either not standardized, pose a biosafety risk, or may lead to increased aggression due to their monopolization by the dominant individual. We have developed the environmental enrichment divider which provides standardized enrichment for zebrafish aquaria mimicking hanging vegetation found in the natural habitat of zebrafish. The divider cannot be monopolized and thereby does not lead to increased aggression. Furthermore, it can easily be implemented in the workflow of any zebrafish research facility and is made of inert, autoclavable plastic, which does not pose a biosafety risk.

This study investigates a novel method to induce mating in zebrafish (Danio rerio) by direct water addition of membrane progestin receptor (mPR) agonists, Org OD 02-0 (Org), or a maturation-inducing steroid, 17α,20β-dihydroxy-4-pregnen-3-one (DHP). Traditional spawning induction methods using hormone injections can be invasive and stressful for fish, especially small fish such as zebrafish. A previous study showed that progestins applied externally to the water can induce oocyte maturation and ovulation in female zebrafish. Then, a recent study showed that the addition of steroids and Org to the water also induced male sexual behavior in zebrafish. Therefore, it was hypothesized that the addition of these compounds to the water could induce mating in zebrafish. To address this, we investigated the efficacy of adding these compounds to the water in the vessel with a pair of zebrafish. Female and male zebrafish pairs were exposed to varying concentrations of DHP or Org in the water, and the resulting spawning rates and rate of sexual behavior induction were recorded. Our results showed that both simple addition of DHP and Org solution successfully induced mating within 4 h. A single chemical induced both spawning in females and sexual behavior in males. In this study, we have established a simple, novel method to induce mating in zebrafish by adding mPR agonists to the water.

The zebrafish is no longer a shy "beginner" but a key model species in neuroscience and drug discovery research. Understanding zebrafish behaviors is important for developing valid models of brain disorders and probing their genetic and environmental causes. The rapid development of zebrafish-based tests and screens also necessitates formal and consistent terminology for the observed phenotypes and behavioral phenomena. To address these needs, in 2013 we compiled a comprehensive 'consensus' glossary of nearly 190 zebrafish behaviors-the Zebrafish Behavior Catalog (ZBC-1) for both larval and adult fish. However, as novel zebrafish behaviors continue to be recognized, an expansion and revision of ZBC were deemed timely. Here, we present the next additional volume of the catalog (ZBC-2), which describes over 120 novel zebrafish behavioral terms and, like the original project, represents a result of a global teamwork of multiple collaborating zebrafish laboratories. Illustrating the value of community efforts to improve data replicability and reliability, this catalog is expected to help interpret research findings, foster cross-domain and cross-species modeling, and encourage new laboratories to study zebrafish behavioral phenotypes.

This study investigates the effects of low-fat diet overfeeding on biological parameters and gut microbiota in adult male zebrafish (Danio rerio). Zebrafish were assigned to four treatment groups: two received control low-fat diets (LF: low-fat; LFA: low-fat with 5% agavins), while the others were overfed these diets (LFO: overfed low-fat; LFAO: overfed low-fat with agavins). Results indicated that low-fat overfeeding led to weight gain and increased biometric indices indicative of overweight and obesity, alongside notable changes in gut microbiota. Agavin supplementation significantly reduced food intake (p < 0.05) and decreased body weight and fat in the overfed groups. Multivariate analyses (permutational multivariate analysis of variance and analysis of similarities) revealed that the LFAO treatment significantly influenced gut microbiota composition, as assessed through 16S ribosomal RNA gene sequencing (V3 region). Noticeable differences in bacterial composition were observed between LFA and LFAO, especially regarding the genera Aeromonas, Paraburkholderia, and an unclassified genus from the Fusobacteriaceae, which contributed to these differences. While dietary factors, specifically agavins, exerted a limited influence on the composition of gut microbiota, the feeding regimen demonstrated a considerable effect.

The first Delhi/NCR Zebrafish Researchers Meeting, held at the Indian Institute of Technology Delhi (IITD) on August 22, 2024, marked a significant step toward initiating collaboration and knowledge exchange among scientists utilizing zebrafish as a model system. This gathering brought together Delhi/NCR region-specific researchers from diverse fields, including developmental biology, toxicology, regeneration, neurobiology, behavior, and disease modeling, to establish a platform for interdisciplinary interaction and scientific advancement. The event featured short talks by principal investigators (PIs), each highlighting their lab's research and the role of zebrafish in their work. Additionally, a student poster session enriched discussions by showcasing cutting-edge applications of zebrafish in fundamental and translational research. The meeting facilitated in-depth conversations on the genetic and molecular manipulability of zebrafish, emphasizing their potential to address complex biological questions. This initiative laid the foundation for a periodic networking event, with participating PIs taking turns as hosts. By uniting experts from various disciplines, the meeting reinforced the importance of collaborative research and innovative approaches, paving the way for expanding zebrafish applications and strengthening the research ecosystem in India.

Over the last few decades, zebrafish have proven to be a valuable tool for biomedical research, with advantages mainly in the use of embryos and adults. The larval stage, on the contrary, is somewhat less used, generally due to a lack of protocols compared with the other stages. In this study, we propose a protocol to study anxiety-like behavior in larvae using the plus maze with ramp (PMR). In the PMR, anxious behavior is measured by the time spent on the flat arms relative to the ramped arms of the apparatus. In the first phase of the study, animals at 5, 14, and 21 days postfertilization (dpf) were exposed to the PMR at different water column heights and session times. It was observed that animals at 14 and 21 dpf were more sensitive to the PMR and exhibited obvious anxiety-like behavior compared with larvae at 5 dpf. In the second phase of the study, to assess the robustness of the type-anxious response exhibited by the larvae, animals at 5, 10, and 14 dpf treated with anxiolytic drugs were exposed to PMR. Alcohol exposure showed a bimodal effect for animals at 10 and 14 dpf, with an anxiolytic effect at intermediate doses, with more exploration of the apparatus and time in the ramp arms. Higher doses caused a reduction in locomotor activity characteristic of drunkenness. Exposure to clonazepam produced anxiolytic effects and a reduction in locomotor activity at the highest dose in 10 and 14 dpf animals. On the contrary, 5 dpf animals showed unexpected effects, which we believe to be related to their stage of development. The results indicate that the PMR is an effective tool for assessing anxiety-like behavior in zebrafish larvae and is sensitive to anxiolytic drugs. Furthermore, anxiety-like behavior appears to vary during the early stages of larval development.