Protoplast 964229 208383993 2008-04-26T20:13:45Z 128.61.112.206 /* Uses for protoplasts */ :''This article discusses protoplasts in the biological sense. For the theological use, see [[Adam and Eve]]'' '''Protoplast''', from the [[ancient Greek]] ''πρώτον'' (first) + verb ''πλάθω'' or ''πλάττω'' (to mould: deriv. ''plastic''), initially referred to the first organized body of a species. This meaning is similar to the non-biological definition, the first from which all subsequent forms are derived. Subsequently it has several biological definitions: *A protoplast is a [[plant]], [[bacterium|bacteria]]l or [[fungus|fungal]] cell that had its [[cell wall]] completely or partially removed using either mechanical or enzymatic means. **Protoplasts - Have their cell wall entirely removed **[[Spheroplast]]s - Have their cell wall only partially removed *More generally ''protoplast'' refers to that unit of biology which is composed of a cell's [[Cell nucleus|nucleus]] and the surrounding [[protoplasm]]ic materials. ==Enzymes for the preparation of protoplasts== Cell walls are made of a variety of [[polysaccharide]]s. Protoplasts can be made by degrading cell walls with a mixture of the appropriate polysaccharide-degrading [[enzyme]]s: {| border="1" cellpadding="2" !Type of cell !Enzyme |- | [[Plant cell]]s |[[Cellulase]], [[pectinase]], [[xylanase]] |- | [[Gram-positive]] bacteria | [[Lysozyme]] (+[[EDTA]]) |- | [[Fungus|Fungal]] cells | [[Chitinase]] |} During and subsequent digestion of the cell wall, the protoplast becomes very sensitive to [[osmosis|osmotic]] stress. This means cell wall digestion and protoplast storage must be done in an [[isotonic solution]] to prevent rupture of the [[plasma membrane]]. ==Uses for protoplasts== Protoplast can be used to study [[biological membrane|membrane]] biology, including the uptake of [[macromolecule]]s and [[virus]]es. Protoplasts are widely used for [[DNA]] [[Transformation (genetics)|transformation]] (for making [[genetically modified organism]]s), since the cell wall would otherwise block the passage of DNA into the cell. Protoplasts may be regenerated into whole plants first by growing into a group of plant cells that develops into a [[Callus (cell biology)|callus]] and then by regeneration of shoots ([[caulogenesis]]) from the callus using [[plant tissue culture]] methods. Growth of protoplasts into callus and regeneration of shoots requires the proper balance of plant growth regulators in the tissue culture medium that must be customized for each species of plant. Protoplasts may also be used for [[plant breeding]], using a technique called [[protoplast fusion]]. Protoplasts from different species are induced to fuse by using an [[electric field]] or a solution of [[polyethylene glycol]]. This technique may be used to generate [[somatic hybrid]]s in tissue culture. [[Category:Membrane biology]] [[Category:Cell biology]] [[Category:Plant physiology]] [[Category:Plant reproduction]] [[Category:Molecular biology]] [[ar:جبلة مجردة]] [[cs:Protoplast]] [[de:Protoplast]] [[es:Protoplasto]] [[eo:Protoplasto]] [[it:Protoplasto]] [[ja:プロトプラスト]] [[pl:Protoplast]] [[ru:Протопласт]] [[sl:Protoplast]] [[tr:Protoplast]]