PVLG Solution，also known as PVLG staining solution, consists of lactic acid, polyvinyl alcohol, glycerol and other components. It is used for staining and detection in fungal identification, such as the staining of arbuscular mycorrhizae. This reagent is commonly used as a mounting medium or floating medium and is often applied together with Melzer’s Reagent (Aladdin Cat. No.: M1508164).
For research‑only use. Not intended for clinical diagnosis or other applications.
Materials to be prepared by user:
1. Test samples, Melzer’s reagent, potassium hydroxide solution
2. Slides, coverslips, microscope, dissecting needle or pipette, forceps
Procedure (for reference only):
1. Add two drops of PVLG solution to one end of the slide, and one drop of PVLG solution plus one drop of Melzer’s reagent to the other end.
2. Pick spores of similar morphology under the microscope. Carefully place approximately 10 spores into the two reagent droplets with a dissecting needle or pipette. Minimize extra water introduced into the reagents when using a pipette.
3. Allow staining for 5 min. Under the microscope, press the coverslip gently with a pencil, forceps or the blunt end of a dissecting needle.
4. Microscopic observation. Examine the specific reaction of spores; take photographs for representative or distinctive features at any time.
Staining Results:
1. Amyloid or Melzer’s positive reaction: The tested tissue appears blue to black.
2. Pseudoamyloid or dextrinoid reaction: The tested tissue appears brown to reddish‑brown.
3. Non‑amyloid or Melzer’s negative reaction: The tested tissue shows no colour change, or appears pale yellowish‑brown.
4. Euthyloid reaction: The tested tissue turns blue without potassium hydroxide pre‑treatment.
5. Hemiamyloid reaction: The tested tissue turns red in Lugol’s solution but shows no reaction in Melzer’s reagent; after potassium hydroxide pre‑treatment, it turns blue in both reagents.
Precautions:
1. Most spores yield different reaction results in Melzer’s reagent and Lugol’s solution. Some spores show no reaction in Melzer’s reagent, while reactions in Lugol’s solution range from faint or no response to iodine‑positive reactions. Some spores exhibit amyloid reaction in Melzer’s reagent but pseudoamyloid reaction in Lugol’s solution.
2. When mixed with alkaline solutions, Melzer’s reagent degrades into turbid precipitates. Therefore, it cannot be mixed or applied sequentially with common mycological reagents such as potassium hydroxide or ammonia water. If pre‑treated with potassium hydroxide, the alkalinity must be neutralized before adding Melzer’s reagent.
3. When Melzer’s reagent is mixed with PVLG solution at a ratio of 1:1, the staining response decreases slightly, yet the colour change is still distinguishable. The mounts are not permanent; staining reactions usually fade within 1–2 years.
4. The purpose of pressing the coverslip after 5 min of incubation is to let the reagent slightly dry, increase edge viscosity and reduce spore sliding out from under the coverslip caused by liquid flow during pressing.
5. Pressing the coverslip under the microscope with a pencil, forceps or the blunt end of a dissecting needle applies indirect pressure to individual spores. Spores receive uneven compression, which helps reveal delicate, elastic inner walls that are normally difficult to observe.
6. For personal safety and health, wear a lab coat and disposable gloves during operation.
7. Use the reagent promptly after opening to avoid compromised experimental results.
Staining Results:
Amyloid reaction: Spores of Lactarius piperatus, 100×
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Dextrinoid reaction: Macrolepiota procera, 100× |
