Assessment of Various Standard Fish Diets on Gut Microbiome of Platyfish Xiphophorus maculatus
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Diet is an important factor affecting experimental reproducibility and data integration across studies. Reference diets for nontraditional animal models are needed to control diet-induced variation. In a study of the dietary impacts on the gut microbiome, researchers found that switching from a custom diet to a zebrafish diet altered the Xiphophorus gut microbiome. Their findings suggest that diets developed specifically for zebrafish can affect gut microbiome composition and might not be optimal for Xiphophorus.
Disentangling the Link Between Zebrafish Diet, Gut Microbiome Succession, and Mycobacterium chelonae Infection
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Despite the long-established importance of zebrafish (Danio rerio) as a model organism and their increasing use in microbiome-targeted studies, relatively little is known about how husbandry practices involving diet impact the zebrafish gut microbiome. Given the microbiome's important role in mediating host physiology and the potential for diet to drive variation in microbiome composition, the authors sought to clarify how three different dietary formulations that are commonly used in zebrafish facilities impact the gut microbiome.
A Comprehensive Drosophila Resource to Identify Key Functional Interactions Between SARS-CoV-2 Factors and Host Proteins
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To address how interactions between SARS-CoV-2 factors and host proteins affect COVID-19 symptoms, including long COVID, and facilitate developing effective therapies against SARS-CoV-2 infections, researchers reported the generation of a comprehensive set of resources, mainly genetic stocks and a human cDNA library, for studying viral–host interactions in Drosophila.
Photoreceptor Disc Incisures Form as an Adaptive Mechanism Ensuring the Completion of Disc Enclosure
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The first steps of vision take place within a stack of tightly packed disc-shaped membranes, or discs, located in the outer segment compartment of photoreceptor cells. In rod photoreceptors, discs are enclosed inside the outer segment and contain deep indentations in their rims called incisures. This presence of incisures has been documented in several species, yet their role remains elusive. This study demonstrated that incisures are formed only after discs become completely enclosed.
The Drosophila Chemokine-Like Orion Bridges Phosphatidylserine and Draper in Phagocytosis of Neurons
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Degenerating neurons can be cleared by phagocytosis triggered by “eat-me” signal phosphatidylserine (PS) and mediated by the engulfment receptor Draper (Drpr), yet the process is poorly understood. Investigators used several Drosophila models to study dendrite degeneration and demonstrated that the fly chemokine-like protein Orion binds to PS and mediates interactions between PS and Drpr to enable phagocytosis. This study identifies a link between immunomodulatory proteins and phagocytosis of neurons and reveals conserved mechanisms of clearing degenerating neurons.
Simultaneous Evaluation of Treatment Efficacy and Toxicity for Bispecific T-Cell Engager Therapeutics in a Humanized Mouse Model
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Immuno-oncology–based therapies are an evolving powerful treatment strategy that targets the immune system and harnesses it to kill tumor cells directly. Investigators describe the novel application of a humanized mouse model that can simultaneously evaluate the efficacy of bispecific T cell engagers to control tumor burden and the development of cytokine release syndrome. The model also captures variability in responses for individual patients. Supported by ORIP (R24OD026440), NIAID, NCI, and NIDDK.
Early Detection of Pseudocapillaria tomentosa by qPCR in Four Lines of Zebrafish, Danio rerio (Hamilton 1882)
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The intestinal nematode Pseudocapillaria tomentosa in zebrafish (Danio rerio) causes profound intestinal lesions, emaciation, and death and is a promoter of a common intestinal cancer in zebrafish. This nematode has been detected in an estimated 15% of zebrafish laboratories. Adult worms are readily detected about 3 weeks after exposure by either histology or wet mount preparations of the intestine, and larval worms are inconsistently observed in fish before this time.
Using Mass Spectrometry Imaging to Map Fluxes Quantitatively in the Tumor Ecosystem
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Mass spectrometry imaging (MSI) can be used to identify metabolic patterns within different microenvironments of tumors but has not been fully integrated into metabolomics workflows. Investigators developed an integrated approach by combining MSI, stable isotope labeling, and a spatial variant of Isotopologue Spectral Analysis to study metabolic pathways across the brains of mice harboring GL261 glioma, a mouse model for glioblastoma. This study reveals the importance of multiple anabolic pathways, including fatty acid elongation flux, in glioma. Supported by ORIP (R24OD024624).
Therapeutic Blocking of VEGF Binding to Neuropilin-2 Diminishes PD-L1 Expression to Activate Antitumor Immunity in Prostate Cancer
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Prostate cancers often escape immune detection and destruction. Investigators report that neuropilin-2 (NRP2), which functions as a vascular endothelial growth factor (VEGF) receptor on tumor cells, is an attractive target to activate antitumor immunity in prostate cancer. They found that NRP2 depletion increased T cell activation in vitro. Additionally, inhibition of the binding of VEGF to NRP2 using a mouse-specific anti-NRP2 monoclonal antibody resulted in necrosis and tumor regression.
High-Resolution Genomes of Multiple Xiphophorus Species Provide New Insights into Microevolution, Hybrid Incompatibility, and Epistasis
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Existing Xiphophorus genome assemblies are not at the chromosomal level and are prone to sequence gaps, hindering advancement of evolutionary, comparative, and translational biomedical studies. Investigators assembled high-quality chromosome-level genome assemblies for three distantly related Xiphophorus species. They found that expanded gene families and positively selected genes associated with live bearing.