Publications by authors named "Kelvin Chen"

Recently, the usage of zebrafish for pain studies has increased in the past years, especially due to its robust pain-stimulated behaviors. Fin amputation has been demonstrated to induce a noxious response in zebrafish. However, based on the prior study, although lidocaine, the most used painkiller in zebrafish, has been shown to ameliorate amputated zebrafish behaviors, it still causes some prolonged effects.

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The distribution of mosquitoes and associated vector diseases (e.g., West Nile, dengue, and Zika viruses) is likely to be a function of environmental conditions in the landscape.

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Ractopamine (RAC) is a synthetic phenethanolamine, β-adrenergic agonist used as a feed additive to develop leanness and increase feed conversion efficiency in different farm animals. While RAC has been authorized as a feed additive for pigs and cattle in a limited number of countries, a great majority of jurisdictions, including the European Union (EU), China, Russia, and Taiwan, have banned its use on safety grounds. RAC has been under long scientific and political discussion as a controversial antibiotic as a feed additive.

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The fin is known to play an important role in swimming for many adult fish, including zebrafish. Zebrafish fins consist of paired pectoral and pelvic with unpaired dorsal, anal, and caudal tail fins with specific functions in fish locomotion. However, there was no study comparing the behavior effects caused by the absence of each fin.

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DeepLabCut (DLC) is a deep learning-based tool initially invented for markerless pose estimation in mammals. In this study, we explored the possibility of adopting this tool for conducting markerless cardiac physiology assessment in an important aquatic toxicology model of zebrafish (). Initially, high-definition videography was applied to capture heartbeat information at a frame rate of 30 frames per second (fps).

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Protozoa are eukaryotic, unicellular microorganisms that have an important ecological role, are easy to handle, and grow rapidly, which makes them suitable for ecotoxicity assessment. Previous methods for locomotion tracking in protozoa are largely based on software with the drawback of high cost and/or low operation throughput. This study aimed to develop an automated pipeline to measure the locomotion activity of the ciliated protozoan using a machine learning-based software, TRex, to conduct tracking.

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Water fleas are an important lower invertebrate model that are usually used for ecotoxicity studies. Contrary to mammals, the heart of a water flea has a single chamber, which is relatively big in size and with fast-beating properties. Previous cardiac chamber volume measurement methods are primarily based on ImageJ manual counting at systolic and diastolic phases which suffer from low efficiency, high variation, and tedious operation.

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Article Synopsis
  • Aptamer selection for new infections is complex, but combining computational and experimental methods can streamline the process.
  • The study introduces a new methodology that includes multiple steps such as molecular design, 3D modeling, molecular docking, dynamics simulations, and experimental verification to develop aptamers targeting the SARS-CoV-2 spike protein.
  • This iterative design procedure, called structure- and interaction-based drug design (SIBDD), enhances the speed and efficacy of aptamer development, offering a framework for creating targeted molecules for emerging pathogens.
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Cardiac arrhythmia has been defined as one of the abnormal heart rhythm symptoms, which is a common problem dealt with by cardiologists. Zebrafish were established as a powerful animal model with a transparent body that enables optical observation to analyze cardiac morphology and cardiac rhythm regularity. Currently, research has observed heart-related parameters in zebrafish, which used different approaches, such as starting from the use of fluorescent transgenic zebrafish, different software, and different observation methods.

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Ractopamine (RAC) is a beta-adrenoceptor agonist that is used to promote lean and increased food conversion efficiency in livestock. This compound has been considered to be causing behavioral and physiological alterations in livestock like pig. Few studies have addressed the potential non-target effect of RAC in aquatic animals.

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In this paper, we review the effects of large-scale neonicotinoid contaminations in the aquatic environment on non-target aquatic invertebrate and vertebrate species. These aquatic species are the fauna widely exposed to environmental changes and chemical accumulation in bodies of water. Neonicotinoids are insecticides that target the nicotinic type acetylcholine receptors (nAChRs) in the central nervous systems (CNS) and are considered selective neurotoxins for insects.

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Tail coiling is a reflection response in fish embryos that can be used as a model for neurotoxic analysis. The previous method to analyze fish tail coiling is largely based on third-party software. In this study, we aim to develop a simple and cost-effective method called TCMacro by using ImageJ macro to reduce the operational complexity.

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Over the last few years, environmental pollution, especially water pollution, has become a serious issue worldwide. Thus, methods that can help us understand the impact and effects of these pollutants, especially on aquatic animals, are needed. Behavioral assessment has emerged as a crucial tool in toxicology and pharmacology because many studies have shown, in multiple animal models, that various pharmacological compounds can alter behavior, with many of the findings being translatable to humans.

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  • The increasing use of pesticides, particularly the toxic carbofuran and copper oxide nanoparticles, is linked to rising food production needs and poses risks to aquatic life.
  • These chemicals were studied for their effects on the cardiovascular system of zebrafish, revealing that their combination leads to increased cardiac edema and disrupted heart rhythms.
  • The findings suggest that carbofuran inhibits acetylcholinesterase activity, exacerbating toxicity when paired with copper oxide nanoparticles, ultimately harming zebrafish larvae's cardiovascular health.
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Recent technological advances have enabled massively parallel chromatin profiling with scATAC-seq (single-cell assay for transposase accessible chromatin by sequencing). Here we present ATAC with select antigen profiling by sequencing (ASAP-seq), a tool to simultaneously profile accessible chromatin and protein levels. Our approach pairs sparse scATAC-seq data with robust detection of hundreds of cell surface and intracellular protein markers and optional capture of mitochondrial DNA for clonal tracking, capturing three distinct modalities in single cells.

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Recently, medaka has been used as a model organism in various research fields. However, even though it possesses several advantages over zebrafish, fewer studies were done in medaka compared to zebrafish, especially with regard to its behavior. Thus, to provide more information regarding its behavior and to demonstrate the behavioral differences between several species of medaka, we compared the behavioral performance and biomarker expression in the brain between four medaka fishes, , , , and .

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  • The transcription factor Foxp3 is essential for the development and function of regulatory T cells (Tregs), but how its expression is controlled during Treg lineage specification is not fully understood.
  • Two specific non-coding sequences (CNS0 and CNS3) near the Foxp3 gene were identified as important regulators, activating early during thymocyte differentiation before Foxp3 itself is activated.
  • Deleting both CNS regions significantly impairs Treg generation and stability, leading to severe autoimmune issues in mice, highlighting their critical roles in maintaining immune tolerance.
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Antidepressants are well-known drugs to treat depression and major depressive disorder for humans. However, the misuse and abuse of antidepressants keep increasing with several side effects reported. The aim of this study was to assess the potential adverse effects of 18 antidepressants by monitoring zebrafish larval locomotor activity performance based on the total distance traveled, burst movement count, and total rotation count at four dark-light intercalated phases.

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As a nicotinoid neurotoxic insecticide, imidacloprid (IMI) works by disrupting nerve transmission via nicotinic acetylcholine receptor (nAChR). Although IMI is specifically targeting insects, nontarget animals such as the freshwater shrimp, , could also be affected, thus causing adverse effects on the aquatic environment. To investigate IMI toxicity on nontarget organisms like , their physiology (locomotor activity, heartbeat, and gill ventilation) and biochemical factors (oxidative stress, energy metabolism) after IMI exposure were examined.

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  • Graphene (GR) and graphene oxide (GO) are potential materials for biomedical uses, but their safety and toxicity require careful evaluation.
  • Adult zebrafish were exposed to different concentrations of GR and GO for 14 days, and their behaviors were assessed through various tests.
  • The study found that exposure to GR and GO altered zebrafish behaviors and neurotransmitter levels, indicating potential toxicity and contributing to the understanding of these materials' biosafety.
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The active site of methanol dehydrogenase (MDH) contains a rare disulfide bridge between adjacent cysteine residues. As a vicinal disulfide, the structure is highly strained, suggesting it might work together with the pyrroloquinoline quinone (PQQ) prosthetic group and the Ca ion in the catalytic turnover during methanol (CHOH) oxidation. We purify MDH from (Bath) with the disulfide bridge broken into two thiols.

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Donepezil (DPZ) is an acetylcholinesterase inhibitor used for the clinical treatment of mild cognitive impairment. However, DPZ has been reported to have adverse effects, including causing abnormal cardiac rhythm, insomnia, vomiting, and muscle cramps. However, the existence of these effects in subjects without Dementia is unknown.

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  • The heart is crucial for pumping blood and delivering oxygen and nutrients, and zebrafish have become a key model organism in cardiotoxicity research due to their unique biological properties.
  • Zebrafish embryos are transparent and can survive without circulation, making them ideal for studying heart-related diseases, while adult zebrafish show remarkable heart muscle regeneration abilities.
  • Various methodologies, including dynamic pixel change, electrocardiography (ECG), and echocardiography, are employed to monitor cardiac rhythm and health in zebrafish, demonstrating their potential as a valuable model for understanding human cardiovascular diseases and drug testing.
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  • * Zebrafish and water flea daphnia were used in this research to assess pesticide toxicity by monitoring changes in locomotor activity after exposure to 12 types of pesticides.
  • * The study found that daphnia exhibited reduced movement (hypo-activity), while zebrafish showed increased movement (hyper-activity) in response to the same pesticides, indicating different sensitivities and responses between the two species.
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In this study, an alternative method is developed to replace chemical synthesis to produce glycyl-histidyl-lysine (GHK) tripeptides with a bacterial fermentation system. The target GHK tripeptides are cloned into expression plasmids carrying histidine-glutathione-S-transferase (GST) double tags and TEV (tobacco etch virus) cleavage sites at the N-terminus. After overexpression in () BL21 cells, the recombinant proteins are purified and recovered by high-pressure liquid chromatography (HPLC).

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