Oxoglaucine

Infectious-disease experiments test how pathogens interact with host barriers, innate immune receptors, inflammatory signaling, pathogen replication, and tissue injury; pattern-recognition receptors such as TLRs, RIG-I-like receptors, NOD-like receptors, and inflammasomes detect microbial molecules and activate NF-κB, interferon, and cytokine responses. The central hypothesis is that infection severity reflects the balance between pathogen burden and host response: protective inflammation restricts pathogen growth, whereas excessive or mislocalized inflammation contributes to tissue damage and disease phenotype. Unresolved questions include which host pathways are protective versus pathogenic, why some infection models fail to translate to human disease, and which combined readouts best predict clinically relevant infection outcomes.

Western blotting (WB) is a commonly used experimental method in molecular biology, biochemistry, and immunogenetics for identifying and quantifying target proteins. It combines gel electrophoresis with immunoassay, enabling researchers to analyze protein expression, post-translational modifications, and molecular weight.

By lysing cells, releasing RNA, and removing impurities such as proteins and DNA, high-purity RNA products are finally obtained. The commonly used traditional method is the guanidine isothiocyanate/phenol/chloroform method (Trizol), which is suitable for a variety of animal materials including animal tissues, microorganisms, cultured cells, etc., and most plant materials.

Sirius Red or picrosirius red staining is a histochemical method for visualizing collagen-rich extracellular matrix in tissue sections, and collagen fibers are detected as red-stained structures under bright-field microscopy with enhanced birefringence under polarized light. Picrosirius red is useful for assessing total collagen organization, distribution, and fibrosis burden, but polarized color should not be interpreted as a definitive collagen type I versus type III readout because color is affected by fiber orientation, thickness, and packing.

Annexin V-based apoptosis assays rely on the detection of phosphatidylserine (PS) externalization from the inner leaflet of the plasma membrane to the outer leaflet, an early biochemical hallmark of apoptosis. Fluorescently labeled Annexin V binds PS in a calcium-dependent manner, enabling identification of early apoptotic cells by flow cytometry or fluorescence microscopy. When combined with a membrane-impermeant DNA-binding dye (e. g. , propidium iodide), this approach allows discrimination between viable (Annexin V−/dye−), early apoptotic (Annexin V+/dye−), and late apoptotic or necrotic (Annexin V+/dye+) cell populations by assessing membrane integrity and PS exposure.

ROS/oxidative-stress fluorescent staining uses cell-permeant fluorogenic probes that become fluorescent after oxidation inside cells or tissues; commonly used examples include DCFH-DA/DCFDA for broad cellular oxidant detection, DHE for superoxide-related signal detection, MitoSOX for mitochondrial superoxide-related signal detection, and CellROX probes for oxidative-stress-associated fluorescence readouts. The assay detects probe oxidation rather than a single ROS species unless the probe and analysis method have been chemically validated for that species. DCFH-DA enters cells, is deacetylated by intracellular esterases to DCFH, and produces fluorescent DCF after oxidation, so the readout is used as an operational measure of total cellular oxidative stress rather than a species-specific ROS measurement. DHE and MitoSOX can report superoxide-related oxidation, but red fluorescence alone can include non-specific ethidium-like oxidation products; HPLC or optimized spectral approaches are

Masson’s Trichrome (collagen/trichrome staining) is a histological technique that differentially stains tissue compartments using sequential acidic dyes to distinguish collagen from muscle and cytoplasmic components based on dye affinity and tissue permeability differences, enabling visualization of fibrosis and connective tissue architecture in histological sections. The classical formulation typically uses Weigert's iron hematoxylin for nuclear staining, Biebrich scarlet-acid fuchsin for cytoplasm and muscle, and aniline blue (or light green variants) for collagen, producing a characteristic blue/green collagen signal contrasted against red cytoplasm and dark nuclei. The staining principle relies on selective displacement of smaller dye molecules by larger anionic dyes in collagen-rich regions under controlled acidified conditions, which enhances collagen-specific dye retention. This property makes the method widely used for fibrosis assessment in organs such as heart, liver, lung, a

The NLRP3 inflammasome is a cytosolic innate immune signaling platform that integrates priming signals and danger-signal activation to promote caspase-1 activation, maturation of IL-1β and IL-18, and gasdermin D-mediated pyroptotic cell death. The core experimental logic is to determine whether inflammatory disease phenotypes are driven by increased NLRP3 expression, ASC-containing inflammasome assembly, caspase-1 cleavage, GSDMD cleavage, and extracellular release of IL-1β/IL-18 rather than by nonspecific cell injury alone. The pathway is strongly linked to inflammation-related disease phenotypes because monosodium urate crystals activate NALP3/NLRP3 inflammasome signaling in gout-like crystal inflammation, cholesterol crystals activate NLRP3 inflammasomes in atherogenesis models, and DSS-induced intestinal inflammation has been reported to involve NLRP3 inflammasome activity. However, experimental colitis studies also show context-dependent protective effects of NLRP3 inflammasome co

Ca²⁺ staining is an experimental technique that utilizes specific fluorescent probes (such as Fluo-4 AM, Fura-2, etc.) to qualitatively or quantitatively detect dynamic changes in intracellular Ca²⁺ concentrations; this is achieved by monitoring the changes in fluorescent signals generated when these probes bind to free intracellular calcium ions. The underlying principle relies primarily on the presence of chelating groups within the probe's molecular structure that possess high affinity for calcium ions.

The LIVE/DEAD bacterial viability staining method is based on differential permeability of nucleic-acid-binding fluorescent dyes, most commonly SYTO 9 and propidium iodide (PI), which enables discrimination of bacterial populations with intact versus compromised cytoplasmic membranes. SYTO 9 penetrates both intact and damaged bacterial membranes and binds nucleic acids to produce green fluorescence, whereas propidium iodide penetrates only cells with compromised membranes and fluoresces red while also reducing SYTO 9 signal through competitive binding and fluorescence interactions. The resulting fluorescence pattern is interpreted as a proxy for membrane integrity, which is widely used as an indicator of bacterial viability in microscopy, flow cytometry, and spectroscopic platforms. However, mechanistic studies show that SYTO 9 and PI interactions involve displacement and fluorescence resonance energy transfer effects, which can influence signal interpretation depending on dye ratios a

Liver histomorphometry is a quantitative histological approach used to measure structural alterations in hepatic tissue, including parenchymal loss, steatosis, fibrosis, and vascular remodeling, by combining stained tissue section analysis with stereological or computerized image-based measurements. Classical morphometric frameworks quantify volume fractions of liver compartments and fibrotic regions using systematic sampling and image analysis, enabling objective comparison of pathological changes across experimental groups. These approaches are widely applied in liver cirrhosis and fibrosis studies to reduce subjectivity in histological scoring and improve reproducibility of tissue evaluation. Recent methodological advances integrate automated image analysis and radiomics-based extraction of histological features from standard liver stains (e. g. , H&E and fibrotic stains), enabling quantitative correlation between morphometric features and fibrosis stages in non-alcoholic fatty live

Kinase activity assays measure the ability of kinases to transfer phosphate groups from ATP to specific substrates, while phosphorylation assays detect the presence and levels of phosphorylated proteins. Common methods include radiolabeled ATP incorporation (e. g. ,), ADP release detection via bioluminescence (e. g. ,[3]), enzyme-linked immunosorbent assays (ELISA) for phospho-specific epitopes (e. g. ,[6]), and microtiter-based formats for high-throughput screening (e. g. ,[8]). The ADP-Glo assay quantifies kinase activity by measuring ADP produced during phosphorylation using a luciferase-based system. Radiometric assays involve autoradiography or scintillation counting after incorporation of ³²P-labeled ATP into substrate proteins. ELISA-based approaches rely on phospho-specific antibodies to detect activated kinases in cell lysates or purified samples.

Fibrosis and collagen morphometry is based on the quantitative visualization of fibrillar collagen deposition in tissue sections using histochemical stains such as Sirius Red (Picrosirius Red) or Masson's trichrome, followed by image-based or polarization-enhanced analysis to estimate collagen proportional area as a surrogate of extracellular matrix accumulation during fibrotic remodeling. Sirius Red combined with polarized light microscopy enhances detection of collagen fibers due to birefringence properties, enabling more specific visualization of collagen type I and III fibrils compared to conventional bright-field histology, while whole-section or region-restricted digital morphometry reduces field-selection bias in fibrosis assessment. Alternative quantitative approaches include second harmonic generation (SHG) and two-photon excited fluorescence microscopy, which enable label-free detection of fibrillar collagen and have been validated against histological staining and biochemica

Collagen-induced arthritis (CIA) is an autoimmune murine model of rheumatoid arthritis in which immunization with type II collagen (CII) emulsified in an adjuvant induces a T cell- and autoantibody-driven inflammatory arthritis characterized by synovial hyperplasia, immune cell infiltration, and joint destruction. The model typically relies on genetically susceptible mouse strains (e. g. , DBA/1) and reproduces key features of human rheumatoid arthritis, including anti-collagen immune responses and progressive joint inflammation. Disease onset generally occurs within ~3-4 weeks after immunization, depending on antigen/adjuvant combinations and protocol variation. The immunopathology is driven by adaptive immune activation against CII, leading to systemic and local joint inflammation mediated by pro-inflammatory cytokines and effector immune cells, making CIA a standard preclinical platform for evaluating immunomodulatory and anti-arthritic interventions.

Apoptosis, also called programmed cell death, is generally characterized by distinct morphological characteristics.

TUNEL staining detects DNA strand breaks by using terminal deoxynucleotidyl transferase to add labeled nucleotides to exposed 3′-OH DNA termini, generating either microscopic staining in fixed cells or tissue sections, or fluorescence/cytometric signal in cell suspensions. TUNEL positivity reflects DNA fragmentation but should not be interpreted alone as definitive apoptosis, because TUNEL can also label necrotic, autolytic, mechanically damaged, or DNA-repair-associated DNA breaks.

Autophagy is a process in which eukaryotic cells use lysosomes to degrade their own cytoplasmic proteins and damaged organelles under the regulation of autophagy related gene (Atg). Microtubule-associated proteins light chain 3 (LC3) is recognized as autophagy marker, which transfers from cytoplasmic LC3 (LC3-I) to membrane type (LC3-II). LC3-II/I ratio could be detected by Western Blot and fluorescence microscopy.

Apoptosis is a regulated, generally non-lytic cell-death pathway that removes unwanted, damaged, infected, or abnormal cells through coordinated morphological changes, caspase activation, DNA fragmentation, and membrane remodeling. The intrinsic apoptosis pathway is controlled mainly by mitochondrial outer membrane permeabilization, BCL-2 family proteins, cytochrome c release, apoptosome formation, caspase-9 activation, and downstream executioner caspase-3/7 activation. The extrinsic apoptosis pathway is initiated by death receptors such as Fas, TNFR, and TRAIL receptors, which recruit adaptor proteins and activate caspase-8 before engaging executioner caspases or mitochondrial amplification through BID cleavage. Apoptosis is linked to many phenotypes, including cancer cell killing, tissue homeostasis, immune regulation, neurodegeneration, infection response, and treatment-induced cytotoxicity; unresolved questions include how apoptosis interacts with necroptosis, pyroptosis, ferroptos

Lysosome and acidic-vesicle live-cell staining detects acidic intracellular compartments by using membrane-permeant acidotropic probes that accumulate in low-pH vesicles, including lysosomes, late endosomes, autolysosomes, and acidic phagosomes. LysoTracker staining is commonly used as an intensity-based readout of acidic lysosomal compartment abundance or enlargement, while acridine orange produces green fluorescence in less concentrated compartments and red fluorescence after concentration-dependent accumulation in acidic vesicular organelles. Loss or reduction of acridine-orange red signal can be used as a readout of lysosomal membrane permeabilization or reduced acidic-vesicle integrity. This protocol is designed for live cultured cells and can be adapted for fluorescence microscopy, high-content imaging, plate-reader readout, or flow cytometry when the selected literature supports the readout. Because these dyes report acidotropic accumulation rather than lysosome identity alone,

Kinase activity assays measure transfer of phosphate from ATP to a protein or peptide substrate, generating phosphorylated substrate, ADP, or incorporated radiolabeled phosphate as the readout; phosphorylation assays measure site-specific phosphorylation in cells or tissues as a proxy for kinase-pathway activation, inhibition, or substrate regulation. Phosphorylation can be detected by phospho-specific Western blot, immunoprecipitation kinase assay, phospho-immunofluorescence, phospho-flow cytometry, luminescent ADP detection, radiolabeled ATP incorporation, or reporter-based pathway assays, and these readouts can be applied to cancer cells, primary neurons, mouse tumors, organoids, inflammatory macrophages, ferroptosis studies, and mitophagy studies when the kinase target is biologically relevant.

Macroautophagy is a conserved lysosome-dependent degradation pathway in which cytoplasmic material is sequestered into double-membrane autophagosomes and delivered to lysosomes for degradation and recycling. The pathway supports cellular homeostasis during nutrient limitation, organelle stress, protein-aggregate accumulation, infection, differentiation, and tissue remodeling by coupling cargo sequestration, autophagosome maturation, lysosomal fusion, and degradation of cargo-derived macromolecules. The core molecular sequence includes initiation by nutrient- and stress-regulated autophagy machinery, autophagosome nucleation, LC3/ATG8-family conjugation to autophagosomal membranes, cargo selection through receptors such as SQSTM1/p62, autophagosome-lysosome fusion, and lysosomal degradation. LC3 was identified as a mammalian homolog of yeast Atg8 that localizes to autophagosomal membranes after processing, and p62/SQSTM1 was shown to connect ubiquitinated cargo with autophagic degradati