斑马鱼生物学效应的研究进展及在水质监测中的应用

主要从不同污染物胁迫介绍了斑马鱼的呼吸行为、运动行为、群体行为等行为学效应,以及个体、器官、细胞、分子等多种水平的毒理效应,同时对斑马鱼行为学和毒理效应在水质监测和水环境评价方面的应用做出介绍和展望,得出综合斑马鱼的行为变化和毒理效应两个方面能更准确地表征水体污染类型及污染程度。     

佤药远志醇提物对斑马鱼的助眠作用

该研究以佤药远志（娘母良）为试材，研究其改善睡眠的功效。采用高效液相色谱法（HPLC）检测佤药远志醇提物的主要活性成分及含量，以斑马鱼为实验动物，建立戊四唑（PTZ）斑马鱼失眠模型。实验设置正常对照组、模型组和处理组，处理组设置5个质量浓度，分别为125、250、500、1 000、2 000 μg/mL，28 ℃处理1 d后，观察统计各组斑马鱼死亡数量和死亡率，测定远志醇提物对正常斑马鱼的最大耐受浓度（Maximum Talerated Concentration，MTC）；根据MTC给予PTZ模型斑马鱼不同质量浓度的远志醇提物，设置阳性对照组（褪黑素组）和正常对照组，通过行为分析仪检测斑马鱼的觉醒活动时间和觉醒活动量。结果表明，MTC为1 000 μg/mL；观察时间内，阳性褪黑素组改善睡眠作用为29.00%，远志醇提物4个质量浓度处理组（125、250、500、 1 000 μg/mL）改善睡眠作用依次为6.97%、22.78%、33.14%、47.26%，其中质量浓度为500 μg/mL和1 000 μg/mL的远志醇提物改善睡眠作用明显优于阳性褪黑素组。以上结果显示远志醇提物对PTZ诱导的斑马鱼失眠症状具有一定的改善作用，但是在一定浓度范围内，呈剂量依赖性，浓度越高，作用越明显。     

Oxytocin Signaling Acts as a Marker for Environmental Stressors in Zebrafish

The oxytocin system plays a role in stress responses and behavior modulation. However, the effects of oxytocin signaling on stress adaptation remain unclear. Here, we demonstrated the roles of oxytocin signaling as a biomarker under stress conditions in the peripheral tissues (the gills) and central nervous system (the brain). All the environmental stressors downregulated the expression of oxytocin receptors in the gills, and the alteration of the expression of oxytocin receptors was also found in the brain after the acidic (AC) and high-ammonia (HA) treatments. The number of oxytocin neurons was increased after double-deionized (DI) treatment. By transgenic line, Tg(oxtl:EGFP), we also investigated the projections of oxytocin neurons and found oxytocin axon innervations in various nuclei that might regulate the anxiety levels and aggressiveness of adult zebrafish under different environmental stresses. The oxytocin system integrates physiological responses and behavioral outcomes to ensure environmental adaptation in adult zebrafish. Our study provides insight into oxytocin signaling as a stress indicator upon environmental stressors.     

Zebrafish Cyclin-Dependent Protein Kinase-Like 1 (zcdkl1): Identification and Functional Characterization

The cyclin-dependent protein kinase family regulates a wide range of cellular functions such as cell cycle progression, differentiation, and apoptosis. In this study, we identified a zebrafish cyclin-dependent protein kinase-like 1 protein called zebrafish cdkl1 (zcdkl1), which shared a high degree of homology and conserved synteny with mammalian orthologs. zcdkl1 exhibited abilities for phosphorylation of myelin basic protein and histone H1. RT-PCR analysis revealed that zcdkl1 was expressed starting from fertilization and continuing thereafter. In adult tissues, zcdkl1 was predominantly detected in brain, ovary, and testis, and was expressed at low levels in other tissues. At 50% epiboly stage, zcdkl1 was widely expressed. At 12 to 48 h post-fertilization, zcdkl1 was predominantly expressed in the hypochord, the medial and lateral floor plate, and the pronephric duct. Interference of zcdkl1 expression resulted in abnormalities, such as brain and eye malformation, pericardial edema, and body axis curvature. Disruption of zcdkl1 reduced neurogenin-1 in the brain and sonic hedgehog expression in the floor plate region. These deformities were apparently rescued by co-injection of zcdkl1 mRNA. Findings of this study indicate that zcdkl1 plays an essential role in zebrafish development.     

Repelled from the wound,or randomly dispersed? Reverse migration behaviour of neutrophils characterized by dynamic modelling

Following neutralization of infectious threats, neutrophils must be removed from inflammatory sites for normal tissue function to be restored. Recently, a new paradigm has emerged, in which viable neutrophils migrate away from inflammatory sites by a process best described as reverse migration. It has generally been assumed that this process is the mirror image of chemotaxis, where neutrophils are drawn into the areas of infection or tissue damage by gradients of chemotactic cues. Indeed, efforts are underway to identify cues that drive neutrophils away by the reverse process, fugetaxis. By using photoconvertible pigments expressed in neutrophils in transparent zebrafish larvae, we were able to image the position of each neutrophil during inflammation resolution in vivo. These neutrophil coordinates were analysed within a dynamic modelling framework, using different forms of the drift–diffusion equation with model selection and parameter estimation based on approximate Bayesian computation. This analysis revealed the experimental data were best fitted by a model incorporating a diffusion term but no drift term—where the presence of drift would indicate fugetaxis. This result, for the first time, provides rigorous data-driven evidence that reverse migration of neutrophils in vivo is not a form of fugetaxis, but rather a stochastic redistribution.     

基因突变斑马鱼骨纳米力学性能的改变

在基因突变的dml型斑马鱼中第一次发现纳米力学性能的明显改变.与野生型斑马鱼骨相比,基因突变的dml型斑马鱼的蚋米压痕的硬度和弹性模量均大大降低.断裂表面的SEM形貌照片进一步揭示了在基因突变的鱼骨中,正常骨的夹板状结构不再存在,形成的微裂纹使力学性能减小,与正常鱼相比,骨的脆性明显增加.     

Renal and Extra Renal Manifestations in Adult Zebrafish Model of Cystinosis

Cystinosis is a rare, incurable, autosomal recessive disease caused by mutations in the CTNS gene. This gene encodes the lysosomal cystine transporter cystinosin, leading to lysosomal cystine accumulation in all cells of the body, with kidneys being the first affected organs. The current treatment with cysteamine decreases cystine accumulation, but does not reverse the proximal tubular dysfunction, glomerular injury or loss of renal function. In our previous study, we have developed a zebrafish model of cystinosis through a nonsense mutation in the CTNS gene and have shown that zebrafish larvae recapitulate the kidney phenotype described in humans. In the current study, we characterized the adult cystinosis zebrafish model and evaluated the long-term effects of the disease on kidney and extra renal organs through biochemical, histological, fertility and locomotor activity studies. We found that the adult cystinosis zebrafish presents cystine accumulation in various organs, altered kidney morphology, impaired skin pigmentation, decreased fertility, altered locomotor activity and ocular anomalies. Overall, our data indicate that the adult cystinosis zebrafish model reproduces several human phenotypes of cystinosis and may be useful for studying pathophysiology and long-term effects of novel therapies.     

Zebrafish Bioassay for Screening Therapeutic Candidates Based on Melanotrophic Activity

In this study, we used the zebrafish animal model to establish a bioassay by which physiological efficacy differential of alpha-melanocyte-stimulating hormone (α-MSH) analogues could be measured by melanosome dispersion in zebrafish larvae. Brain-skin connection research has purported the interconnectedness between the nervous system and skin physiology. Accordingly, the neuropeptide α-MSH is a key regulator in several physiological processes, such as skin pigmentation in fish. In mammals, α-MSH has been found to regulate motivated behavior, appetite, and emotion, including stimulation of satiety and anxiety. Several clinical and animal model studies of autism spectrum disorder (ASD) have already demonstrated the effectiveness of α-MSH in restoring the social deficits of autism. Therefore, we sought to analyze the effect of synthetic and naturally-occurring α-MSH variants amongst different species. Our results showed that unique α-MSH derivatives from several fish species produced differential effects on the degree of melanophore dispersion. Using α-MSH human form as a standard, we could identify derivatives that induced greater physiological effects; particularly, the synthetic analogue melanotan-II (MT-II) exhibited a higher capacity for melanophore dispersion than human α-MSH. This was consistent with previous findings in an ASD mouse model demonstrating the effectiveness of MT-II in improving ASD behavioral symptoms. Thus, the melanophore assay may serve as a useful screening tool for therapeutic candidates for novel drug discovery.     

Discovery,Synthesis, and Optimization of Diarylisoxazole‐3‐carboxamides as Potent Inhibitors of the Mitochondrial Permeability Transition Pore

The mitochondrial permeability transition pore (mtPTP) is a Ca²⁺‐requiring mega‐channel which, under pathological conditions, leads to the deregulated release of Ca²⁺ and mitochondrial dysfunction, ultimately resulting in cell death. Although the mtPTP is a potential therapeutic target for many human pathologies, its potential as a drug target is currently unrealized. Herein we describe an optimization effort initiated around hit 1 , 5‐(3‐hydroxyphenyl)‐N‐(3,4,5‐trimethoxyphenyl)isoxazole‐3‐carboxamide, which was found to possess promising inhibitory activity against mitochondrial swelling (EC₅₀<0.39 μM ) and showed no interference on the inner mitochondrial membrane potential (rhodamine 123 uptake EC₅₀>100 μM ). This enabled the construction of a series of picomolar mtPTP inhibitors that also potently increase the calcium retention capacity of the mitochondria. Finally, the therapeutic potential and in vivo efficacy of one of the most potent analogues, N‐(3‐chloro‐2‐methylphenyl)‐5‐(4‐fluoro‐3‐hydroxyphenyl)isoxazole‐3‐carboxamide ( 60 ), was validated in a biologically relevant zebrafish model of collagen VI congenital muscular dystrophies.