L-forms

L-forms

[named for Lister Institute]
Spontaneous variants of bacteria that replicate as filterable spheres with defective or absent cell walls. They are filterable because of their flexibility rather than their size. Stable forms may grow for an indefinite time in a wall-less state. Organisms of the unstable form are capable of regenerating their cell walls and reverting to their antecedent bacterial form. The ability of L-forms to cause disease is unknown.
Synonym: L-phase variants
References in periodicals archive ?
It is a development from previous work done in the Errington Lab on bacterial variants - called L-forms - which lack a cell wall and can grow if they have some protection, which human tissue allows.
Although L-forms are much more fragile than walled cells, because they are completely resistant to penicillins and related antibiotics, they may be contributing substantially to problems of persistence or recurrence of infection, which is a frequent clinical problem.
The study was funded by the European Research Council and further research at the Errington Lab is focusing on the importance of L-forms in recurrent urinary tract infections.
If penicillin-treated cells in tissue fluid are exposed to lysozyme - found in places in the body where infections occur - the enzyme degrades the cell wall, allowing the bacterium to turn into a wall free L-form, which penicillin can't kill.
The results of our study have important implications because they suggest that the L-form transition may be occurring frequently during infection.
L-forms are very heterogeneous insize and shape and generally require osmotic stabilisers, such as 0.
MacDonald describes L-forms as "sort of like soap bubbles that can stretch out and contain various boundaries, and are not as easy to identify as spirochetes.
Armstrong said their method is very selective at separating out the D- and L-forms.
We analyzed the data of Table II to compare these two alternatives-the more traditional A or A-W forms with the two L-forms (L-A and A-L).
In our view, L-forms (here, the L-A and A-L forms; more generally, any form that separates developers from maintainers) offer certain important advantages for the contemporary IS organization.
This suggests that the overall strengths and weaknesses of L-forms should be examined more closely.
A first strength of the L-forms is clear accountability for both maintenance expenses and the investment costs of new system development, which has long been a problem for IS management.