Espazo periplásmico: Diferenzas entre revisións

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Nova páxina: "{{entradución}} thumb|right|250px|[[Gram negative cell wall]] The '''periplasm''' is a space bordered by two selective permeable barrier..."
 
Miguelferig (conversa | contribucións)
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Liña 1:
{{entradución}}
[[ImageFicheiro:Gram negative cell wall.svg|thumbminiatura|rightdereita|250px|[[GramParede negativecelular]] dunha bacteria [[cellGram wallnegativa]].]]
TheO '''periplasmespazo periplásmico''' isou '''periplasma''' é o espazo que rodea a spacedúas borderedbarreiras byde twopermeabilidade selectiveselectiva permeablena barriers,cuberta i.e.das biological membranesbacterias, whichcomo areson thea [[innermembrana membraneplasmática]] (i.e.ou [[cytoplasmicmembrana membrane]])interna ande thea [[Bacterialmembrana outerexterna membrane|outerdas membrane]] inbacterias [[Gram-negative]] [[bacterium|bacterianegativa]]s. Strictly speaking, there is no '''periplasmic space''' in [[Gram-positive]] [[bacterium|bacteria]] because there is only one biological membrane, the [[cytoplasmic membrane]], but a region termed '''inner wall zone (IWZ)''' has been observed between the [[cytoplasmic membrane]] and the mature [[cell wall]].<ref name="Matias & Beveridge, 2005">, Matias, V. R., and T. J. Beveridge. 2005. Cryo-electron microscopy reveals native polymeric cell wall structure in Bacillus subtilis 168 and the existence of a periplasmic space. Mol. Microbiol. 56:240-251. {{doi|10.1111/j.1365-2958.2005.04535.x}}.</ref><ref name="Zuber et al, 2006">, Zuber B, Haenni M, Ribeiro T, Minnig K, Lopes F, Moreillon P, Dubochet J. 2006. Granular layer in the periplasmic space of Gram-positive bacteria and fine structures of Enterococcus gallinarum and [[Streptococcus gordonii]] septa revealed by cryo-electron microscopy of vitreous sections. J Bacteriol. 188:6652-6660. {{doi|10.1128/​JB.00391-06}}</ref>
The '''periplasm''' may constitute up to 40% of the total cell volume in [[Gram-negative]] species, whereas the '''IWZ''' is drastically smaller in [[Gram-positive]] species.<ref name="isbn3-540-42608-6">{{cite book |author=Otto Holst; Guntram Seltmann |title=The Bacterial Cell Wall |publisher=Springer |location=Berlin |year= |pages= |isbn=3-540-42608-6 |oclc= |doi=}}</ref> Composition of the '''IWZ''' has not been as yet clearly determined.
 
Liña 8:
In diderm [[bacterium|bacteria]], the '''periplasm''' contains a thin [[cell wall]] composed of [[peptidoglycan]]. In addition, it includes solutes such as ions and proteins, which are involved in wide variety of functions ranging from nutrient binding, transport, folding, degradation, substrate hydrolysis, to [[peptidoglycan]] synthesis, [[electron transport]], and alteration of substances toxic to the cell ([[xenobiotic metabolism]]).<ref name="isbn0-07-295175-3">{{cite book |author=Klein, Donald W.; Prescott, Lansing M.; Harley, John |title=Microbiology |publisher=McGraw-Hill Higher Education |location=Boston |year=2005 |pages= |isbn=0-07-295175-3 |oclc= |doi=}}</ref> Importantly, the periplasm is devoided of ATP.
 
==ReferencesNotas==
{{reflistlistaref}}
 
==FurtherVéxase readingtamén==
===Outros artigos===
* [[Parede celuular]]
* [[Bacteria Gram positiva]]
* [[Bacteria Gram negativa]]
 
===Outras lecturas===
* D. White, The Physiology and Biochemistry of Prokaryotes, Oxford University Press, Oxford, 2000, pp.&nbsp;22.
 
{{Bacteria}}
 
 
[[Category:Cell anatomy]]
[[Categoría:Bacterias]]
[[Category:Bacteriology]]
 
 
[[cs:Periplazmatický prostor]]