= Lysozyme wall-removal experiment
The 1953 paper <The isolation of protoplasts from Bacillus megaterium by controlled treatment with lysozyme by Claes Weibull> (pp. 688–690, Figures 2–3) tested <Bacillus megaterium> strain KM. Apparatus included a Klett-Summerson colorimeter with a red filter and a Spencer no. 8 <phase-contrast microscope>. <Lysozyme> in phosphate buffer produced empty residual bodies; adding $0.2\,\mathrm{M}$ <sucrose> preserved granular spheres. Diluting their surroundings caused rapid <osmotic lysis>.
The same study compared untreated, boiled, <lysozyme>-exposed and <sucrose>-protected samples. Filled, stoppered tubes reduced damage from air exposure. After <centrifugation>, a Beckman DU spectrophotometer measured ultraviolet <wave absorption> of the separated liquid. Protected samples resembled untreated controls in releasing little ultraviolet-absorbing material; boiled and unprotected samples released much more. Later-growth cultures reduced spontaneous breakdown as a confounder.<The isolation of protoplasts from Bacillus megaterium by controlled treatment with lysozyme by Claes Weibull>[pp. 688–689, Materials and Methods; pp. 692–694, release comparison and Figure 6]{ref}
Together, the shape and release readouts support removal of mechanical protection while a permeability barrier persists. They do not establish unchanged <selective permeability> to every <solute>, long-term viability, or universal susceptibility.
An instructive extension of this experimental logic is a matched comparison: <lysozyme> present or absent, crossed with osmotic support present or absent. Keep starting material, buffer, observation interval and handling comparable; include a blank to distinguish optical effects of reagents from changes in the <biological cells>. Then dilute already formed <protoplasts> as a separate intervention. This separates access and wall removal from failure after removal. These are proposed controls for interpreting the mechanism, not additional reported results from the historical paper. A fall in optical signal alone cannot establish rupture: shape changes also alter <scattering of light>.
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