Corrigendum: Lineage Tracing and Fate Mapping in Xenopus Embryos
Cold Spring Harb Protoc 2018; doi: 10.1101/pdb.prot097253
In earlier versions of this protocol, the chemical names for the formulas Na2HPO4 and NaH2PO4 were inadvertently reversed: Na2HPO4 should have been defined as the dibasic phosphate, and NaH2PO4 should have been defined as the monobasic phosphate. The HTML versions of the two recipes in which the error appeared, “Paraformaldehyde (4% in PBS)” (doi: 10.1101/pdb.rec104588) and “Phosphate-Buffered Saline (PBS) (0.1 m, pH 7.4)” (doi: 10.1101/pdb.rec104604), have been corrected, as has the most recent PDF version of the protocol. Corrected versions of the recipes are also included below.
Paraformaldehyde (4% in PBS)
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1. Add 4 g of paraformaldehyde to a beaker containing 40 mL of distilled H2O. Cover with foil and heat to 60°C in a chemical fume hood with constant stirring. Do not let the temperature rise above 65°C.
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2. Add 1 n NaOH drop-wise, while stirring, until the solution just clears. Cool the solution on ice to room temperature.
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3. Add 0.9 g of NaCl and stir until dissolved.
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4. Add 40 mL of 0.2 m dibasic (Na2HPO4) phosphate buffer (PB) stock (pH 7.4) and 10 mL of monobasic (NaH2PO4) PB stock (pH 7.4).
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Prepared PB stocks can be stored at room temperature for months.
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5. Bring the volume to 100 mL with distilled H2O.
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6. Mix thoroughly and store in the refrigerator or freezer (−20°C) in small, single-use aliquots for months.
Phosphate-Buffered Saline (PBS) (0.1 m, pH 7.4)
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1. Mix 40 mL of 0.2 m dibasic (Na2HPO4) phosphate buffer (PB) stock with 10 mL of monobasic (NaH2PO4) PB stock.
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Prepared PB stocks can be stored at room temperature for months.
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2. Add 0.9 g NaCl and stir until dissolved.
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3. Bring the volume to 100 mL with distilled H2O and adjust the pH to 7.4.
