n.
A bacterial cell whose cell wall is absent or deficient, causing it to have a spherical form.
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spheroplast
American Heritage Dictionary:
spher·o·plast |
n.
A bacterial cell whose cell wall is absent or deficient, causing it to have a spherical form.
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Oxford Dictionary of Biochemistry:
spheroplast |
the globular form of a bacterial cell in which the cell-wall structure has been modified (e.g. by growth in the presence of penicillin) rather than totally removed. The term also denotes a form of yeast cell obtained by partial hydrolysis of the cell wall. A prefix may be used to indicate the method of induction, e.g. penicillin-spheroplast. Compare protoplast.
| spheroid, spherocytosis, spherocyte | |
| spherosome, sphinganine, sphingoid |
Saunders Veterinary Dictionary:
spheroplast |
Gram-negative bacterial cell deprived of its cell wall, but retaining an intact plasma membrrane. See also protoplast.
Wikipedia on Answers.com:
Spheroplast |
A spheroplast is a cell from which the cell wall has been almost completely removed, as by the action of penicillin. The name stems from the fact that after a microbe's cell wall is digested, membrane tension causes the cell to acquire a characteristic spherical shape. Spheroplasts are osmotically fragile, and will lyse if transferred to a hypotonic solution.
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Contents
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Uses and applications
Patch clamping
Specially prepared giant spheroplasts of Gram-negative bacteria can be used to study the function of bacterial ion channels through a technique called patch clamp, which was originally designed for characterizing the behavior of neurons and other excitable cells. To prepare giant spheroplasts, bacteria are grown in a medium containing chemicals that prevent the cells from dividing completely. This causes bacteria to form long "snakes" that share a single membrane and cytoplasm. After a period of time, the cell walls of the "snakes" are digested, and the bacteria collapse into very large spheres surrounded by a single lipid bilayer. The membrane can then be analyzed on a patch clamp apparatus to determine the phenotype of the ion channels embedded in it. It is also common to overexpress a particular channel to amplify its effect and make it easier to characterize.
The technique of patch clamping giant E. coli spheroplast have been used extensively for studying the native mechanosensitive channels (MscL, MscS, and MscM) of E. coli since 1987.[1][2] Recently, it has been extended to study other heterologously expressed ion channels and has been shown that the giant E. coli spheroplast can be used as an ion-channel expression system comparable to Xenopus oocyte.[3][4][5][6]
Cell lysis
Yeast cells are normally protected by a thick cell wall which makes extraction of cellular proteins difficult. Enzymatic digestion of the cell wall with zymolyase, creating spheroplasts, renders the cells vulnerable to easy lysis with detergents or rapid osmolar pressure changes.
Transfection
Bacterial spheroplasts, with suitable recombinant DNA inserted into it, can be used to transfect animal cells. Spheroplasts with recombinant DNA are introduced into the media containing animal cells and are fused by polyethylene glycol (PEG). With this methodology, nearly 100% of the animal cells may take up the foreign DNA.
See also
References
- ^ Martinac, B., Buechner, M., Delcour, A. H., Adler, J., and Kung, C. (1987) Pressure-sensitive ion channel in Escherichia coli. Proc. Natl. Acad. Sci. USA 84, 2297-2301.
- ^ Blount, P., Sukharev, S. I., Moe, P. C., Martinac, B., and Kung, C. (1999) Mechanosensitive channels of bacteria. Methods in Enzymology 294, 458-482.
- ^ Santos, J. S., Lundby, A., Zazueta, C., and Montal, M. (2006) Molecular template for a voltage sensor in a novel K+ channel. I. Identification and functional characterization of KvLm, a voltage-gated K+ channel from Listeria monocytogenes. Journal of General Physiology 128(3), 283-292.
- ^ Nakayama, Y., Fujiu, K., Sokabe, M., and Yoshimura, K. (2007) Molecular and electrophysiological characterization of a mechanosensitive channel expressed in the chloroplasts of Chlamydomonas. Proc. Natl. Acad. Sci. USA 104, 5883-5888.
- ^ Kuo, M. M.-C., Baker, K. A., Wong, L., and Choe, S. (2007) Dynamic oligomeric conversions of the cytoplasmic RCK domains mediate MthK potassium channel activity. Proc. Natl. Acad. Sci. USA 104, 2151-2156.
- ^ Kuo, M. M.-C., Saimi, Y., Kung, C., and Choe, S. (2007). Patch-clamp and phenotypic analyses of a prokaryotic cyclic nucleotide-gated K+ channel using Escherichia Coli as a host. J. Biol. Chem. 282, 24294-24301.
External links
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
Related topics:
 | protoplast |
| Burrill Bernard Crohn |
| Patch clamp |
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Copyrights:
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 | American Heritage Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved. Read more |
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Oxford Dictionary of Biochemistry. Oxford University Press. Oxford Dictionary of Biochemistry and Molecular Biology © 1997, 2000, 2006 All rights reserved. Read more | |
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| Saunders Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more |
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| Wikipedia on Answers.com. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article Spheroplast. Read more |
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