Protoplast

When protoplast is a term used provided with cell walls of cells, the smallest independently viable morphological unit, ie the plasmatic contents of a cell. Therefore, there is the term in bacteria, fungal and plant cells, as they can have any cell wall. On the other hand, animal cells have no cell wall and are limited only by their plasma membrane.

Protoplasts without cell wall makes it by the cell wall by enzymes is dissolved ( protoplast isolation). In bacteria, the murein layer ( cell wall ) is dissolved by EDTA and lysozyme, in plant cells, cellulose and pectin of the cell wall can be subdivided by cellulases and pectinases. When equipped with different type of cell walls of fungi can be moved accordingly by other means, for example, chitin cell walls may be dissolved by chitinase.

In bacterial cells is called depending on the completeness of the removal of

• Protoplasts (no murein available)
• Spheroplasts ( murein residues are present )

However, the unit membrane / cytoplasmic membrane ( cell membrane ) is retained in each case. However, it is necessary to prepare the protoplasts in an osmotically approximately isotonic medium and to hold, otherwise they take in hypotonic medium water and burst or is withdrawn from them in hypertonic water and they shrink thereby.

Use

Since protoplasts have no cell walls, they can easily accommodate DNA. Therefore, they are the starting material for the production of transgenic plants, in particular in those plants in which an Agrobacterium tumefaciens -mediated DNA transfer has not been established. Protoplasts can be fused together ( protoplast fusion). For example, two cells and two genomes may be fused together, even if the starting organisms could not be crossed each other; it caused somatic hybrids. This technique is i.a. used in plant breeding. The protoplasts from vascular plants require the addition of phytohormones for regeneration into whole plants. Mostly running this regeneration via an intermediate stage, the so-called callus from. In contrast, regenerate the protoplasts of mosses such as Physcomitrella patens without addition of phytohormones directly to filamentous protonema. They behave like a germinating moss spore.

Credentials

• Cell Biology