Description
X-Gluc (CHX Salt) is a high-purity chromogenic substrate used for detecting β-glucuronidase (GUS) activity in molecular biology and microbiology research. This form yields vivid indigo-blue staining upon enzymatic cleavage, enabling precise visualization of gene expression in plant tissues, microbial colonies, and environmental systems.
Ideal for histochemical assays, transformation screening, and E. coli contamination detection, X Gluc (CHX) is optimized for high solubility, long-term stability. Trusted in both academic and applied settings, GoldBio’s X-Gluc is the preferred substrate for sensitive, publication-grade GUS assays.
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Purity: greater than 99% (HPLC)
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Thin Layer Chromatogram: single spot
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Biological Activity: indigo-blue assay
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Elemental Analysis: Agrees with theoretical values
Common Applications:
(Click each for more information)
Histochemical Detection of Gene Expression in Transgenic Plants (GUS Reporter Assay)
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Purpose: Localize gene expression patterns in plant tissues using GUS reporter constructs.
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How It Works: X-Gluc serves as a chromogenic substrate for β-glucuronidase (GUS); when cleaved, it forms an insoluble indigo-blue precipitate, revealing the precise location of GUS expression.
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Applications: Commonly used in Arabidopsis thaliana, tobacco, maize, and rice to study promoter activity, assess tissue-specific gene expression, and validate transgene integration.
Jefferson, R. A., Kavanagh, T. A., & Bevan, M. W. (1987). GUS fusions: β-glucuronidase as a sensitive and versatile gene fusion marker in higher plants. The EMBO Journal, 6(13), 3901–3907.
Quantitative Measurement of GUS Enzyme Activity
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Purpose: Measure GUS activity in cell extracts or lysates to quantify promoter strength and transgene expression.
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How It Works: X-Gluc is enzymatically hydrolyzed by GUS to produce a colored product, which can be measured spectrophotometrically. The color intensity correlates with enzyme activity.
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Applications: Screening transgenic lines, comparing promoter constructs, and evaluating tissue-specific expression levels.
Gallagher, S. R. (1992). Quantitation of GUS activity by spectrophotometry. In S. R. Gallagher (Ed.), GUS Protocols: Using the GUS Gene as a Reporter of Gene Expression (pp. 47–59). Academic Press.
Detection of Escherichia coli Contamination in Water and Food Testing
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Purpose: Identify GUS-positive E. coli strains through rapid chromogenic colony screening.
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How It Works: GUS-expressing E. coli hydrolyze X-Gluc, resulting in blue-colored colonies on selective media. This method offers high specificity for detecting coliform bacteria.
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Applications: Microbial quality control for potable water, dairy, meats, and clinical sample testing.
Manafi, M., Kneifel, W., & Bascomb, S. (1991). Fluorogenic and chromogenic substrates used in bacterial diagnostics. Microbiological Reviews, 55(3), 335–348.
Visual Screening of GUS-Expressing Bacteria in Transformation and Environmental Studies
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Purpose: Identify bacterial colonies expressing the gusA gene through visual blue-color development.
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How It Works: Engineered bacteria hydrolyze X-Gluc on solid media, forming a blue precipitate indicative of GUS activity.
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Applications: Monitoring gene transfer, confirming transformation events, and tracking GUS-labeled strains in microbial ecology and plant-microbe interaction studies.
Wilson, K. J., Hughes, S. G., & Jefferson, R. A. (1992). The Escherichia coli gus operon: induction and expression of the gus operon in E. coli and the occurrence and use of GUS in other bacteria. In S. R. Gallagher (Ed.), GUS Protocols: Using the GUS Gene as a Reporter of Gene Expression (pp. 7–22). Academic Press.
Tissue-Specific Gene Expression Studies in Plant Development and Stress Response
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Purpose: Investigate the spatial and temporal dynamics of gene regulation in response to developmental or environmental stimuli.
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How It Works: Promoters of interest are fused to gusA, and GUS activity is detected via X-Gluc staining in specific plant tissues.
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Applications: Root development, hormone signaling (e.g., auxin, cytokinin), and abiotic stress responses such as salinity and drought.
Chen, Q., Dai, X., & Zhao, Y. (2011). Auxin overproduction in shoots cannot rescue auxin deficiencies in Arabidopsis roots. Plant & Cell Physiology, 52(7), 1071–1076.
Benefits:
- High-contrast visualization: Produces a robust indigo precipitate for precise localization of GUS expression.
- Reliable transgene screening: Validated in thousands of plant transformation protocols.
- Cross-species utility: Compatible with plants, bacteria, and environmental isolates.
- Minimal diffusion in tissue: When paired with potassium ferricyanide, allows pinpoint GUS signal without spread.
- Flexible assay formats: Enables both qualitative (histochemical) and quantitative (spectrophotometric) analysis of reporter activity.
- Long shelf life & consistent results: CHX salt form offers superior handling and solubility compared to sodium salt variants.
Storage/Handling:
Store desiccated at -20°C. Protect from light.
Soluble in DMF.
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