Many Gram-negative bacteria are capable of switching to a cell wall deficient state known as an L-form. These "L"-forms were first identified at the "L"ister Institute and hence their name. We are trying to screen for genetically stable L-forms of Salmonella and were wondering if any other scientist had generated or come across these L-forms in Salmonella?
Up to now to my knowledge all L forms of Salmonella has been reversible. Having a stable L forms as happens in Gram positive bacteria has not beebn found.
Thank you Terzoio for your valuable comments. There was a group in Nara Medical University, Japan, who published some work on "stable" L-forms in the 1990's. These studies were largely from an immunity perspective. Nothing more has been published since then from the group who include the author Kita. I havent been able to access their detailed methods yet for production of L-forms, as we dont have a subscription to those journals, but they appear to use media selection and expect they may not be genetically stable.
Thank you for your interesting comments. It would be interesting to get this journal. Do you have more details regarding this publication? Regards.
Thank you, I have attached a PDF of the publication by Kita et al citing the methodology in additional references numbered 3 and 8. My university library do not have online subscriptions to the cited journals.
Dear Bernt-Dieter, Some land-mark work has been done by Jeff Errington here in Newcastle in the Gram-positve Bacillus. These are described in a number of publications in Nature, Cell, and Cell Reports, and I attach a review just published in Open Biology. The L-forms which lack a cell wall, are also resistant to the effects of antibiotics. If I can do anything else to help please let me know. Anjam
Thank you for all your information!
Please can anyone get this paper, becauese in INTERNET only the first 100 words are shown.
Biology and Pathogenicity of Microbial Spheroplasts and L-Forms
David S. Feingold, M.D.
N Engl J Med 1969; 281:1159-1170November 20, 1969
This article has no abstract; the first 100 words appear below.
Regards to all,
Horacio Terzolo
Dear Bernt-Dieter Huismans:
Please this medical review article willbe interesting to you!
Regards,
Horacio Raúl Terzolo
Dear All:
There is a paper describing the survival of E. coli L forms after heating at 100°C and autoclaving modifing old concepts of bacteriology. Has anybody read this article?
Markova N, Slavchev G, Michailova L, Jourdanova M. Survival of Escherichia coli under lethal heat stress by L-form conversion. Int J Biol Sci 2010; 6(4):303-315. doi:10.7150/ijbs.6.303.
Available from:
http://www.ijbs.com/v06p0303.htm
Regards,
Horacio Terzolo
PS: PDF Attached
Here the file in PDF:
Markova N, Slavchev G, Michailova L, Jourdanova M. Survival of Escherichia coli under lethal heat stress by L-form conversion. Int J Biol Sci 2010; 6(4):303-315. doi:10.7150/ijbs.6.303.
Dear Horacio , Thank you for forwarding the pdf's of the articles and also for forwarding the clinically orientated pdf to Bernt-Deieter. I too can only access the first 100 words or so of the article Biology and Pathogenicity of Microbial Spheroplasts and L-Forms in New Eng J of Med 1969. Kind regards, Anjam
Dear Bernt-Dieter Huismans, Thank very much for helping with this difficult to get paper!
Best regards,
Horacio Terzolo
Great, thank you for the paper. In contrast to Gram-positives as Horacio Terzolo also mentions, there are no reports of genetically stable L-forms in Gram-negatives. L-forms can be generated in Gram-negatives under stress but can they be maintained without stress..? Kind regards, Anjam
Some nice links on the shape-shifters. One of the reasons we are interested in the round shaped L-forms is related to our interest in the role of the bacterial cytoskeleton in the biology and pathogenicity of Salmonella. When we introduced a mutation within the actin-like MreB protein in Salmonella they shifted shape from rod-shaped cells to round-shaped cells ! This also had an impact on the expression of virulence factors and pathogenesis in vivo. I will forward the PDF's for those papers from my group.
Dear Dr. Anjam Khan, Please could you make available here the PDF about Salmonella cytoskeleton?
Thank you
Dear Dr. Anjam Khan, According to general text books stable L forms of Gram negative bacteria, such as the case of Salmonella, can only be produced when there is a genetical change, as for instance forced by some laboratory procedures. May be this stable L forms permanently loss their pathogenicity. The natural L of Salmonella forms are produced in a reversible way without any genetic changes and explain its vertical transference through eggs form the hen to the chicken, maintaining its pathogenicity.
Regards,
Dr. Horacio Terzolo
Dear Horacio, Thank you for your comments. Here is the cytoskeleton PDF if you did not receive it, Thanks, Anjam
Dear Bernt, Thats a very interesting thought regarding a symbiotic brain, and the possible role of microbes. Some interesting concepts also on microtubules and the digital brain. These host-microbe interactions are also an area we are interested in, then appears to be a chemical language which enables signalling/communication between the host and pathogen. I will send you a PDF of our latest review.
Kind regards, Anjam
Here is the PDF of our latest review on inter-kingdom communication between pathogens and hosts, Karavolos et al 2013.
Kind regards, Anjam
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