Gram-Negative Bacteria Periplasm

A Gram-Negative Bacteria Periplasm is the periplasmic space between the Inner Cytoplasmic Membrane and the External Outer Membrane in a Gram-Negative Bacteria.

• Context:
  • It can contain Murein Chains.
  • It can contain Hydrolytic Enzymes.
  • It can contain Degradative Enzymes.
  • …
• Counter-Example(s)
  • Gram-Positive Bacteria Periplasm.
• See: Fungi Periplasm, Septal Periplasm, Cytoplasm, Cell Membrane, Microbiology, Pseudomonas Aeruginosa, Neisseria Gonorrhoeae, Chlamydia trachomatis, Yersinia Pestis, Streptococcus Gordonii.

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References

2018a

• (Wikipedia, 2018a) ⇒ https://en.wikipedia.org/wiki/Gram-negative_bacteria Retrieved:2018-4-29.
  • Gram-negative bacteria are a group of bacteria that do not retain the crystal violet stain used in the gram-staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane.

    Gram-negative bacteria are found everywhere, in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism Escherichia coli, as well as many pathogenic bacteria, such as Pseudomonas aeruginosa, Neisseria gonorrhoeae, Chlamydia trachomatis, and Yersinia pestis. They are an important medical challenge, as their outer membrane protects them from many antibiotics (including penicillin); detergents that would normally damage the peptidoglycans of the (inner) cell membrane; and lysozyme, an antimicrobial enzyme produced by animals that forms part of the innate immune system. Additionally, the outer leaflet of this membrane comprises a complex lipopolysaccharide (LPS) whose lipid A component can cause a toxic reaction when these bacteria are lysed by immune cells. This toxic reaction can include fever, an increased respiratory rate, and low blood pressure — a life-threatening condition known as septic shock.

    Several classes of antibiotics have been designed to target gram-negative bacteria, including aminopenicillins, ureidopenicillins, cephalosporins, beta-lactam-betalactamase combinations (e.g. pipercillin-tazobactam), Folate antagonists, quinolones, and carbapenems. Many of these antibiotics also cover gram positive organisms. The drugs that specifically target gram negative organisms include aminoglycosides, monobactams (aztreonam) and Ciprofloxacin.

2018b

• (Wikipedia, 2018b) ⇒ https://en.wikipedia.org/wiki/Periplasm Retrieved:2018-4-29.
  • The periplasm is a concentrated gel-like matrix in the space between the inner cytoplasmic membrane and the bacterial outer membrane called the periplasmic space in gram-negative bacteria. Using cryo-electron microscopy it has been found that a much smaller periplasmic space is also present in gram-positive bacteria.

    The periplasm may constitute up to 40% of the total cell volume of gram-negative bacteria, but is a much smaller percentage in gram-positive bacteria.

    Although the bacteria are conventionally divided into two main groups — gram-positive and gram-negative, based upon their Gram-stain retention property — this classification system is ambiguous as it can refer to three distinct aspects (staining result, cell-envelope organization, taxonomic group), which do not necessarily coalesce for some bacterial species. However, although Gram-staining response of bacteria is an empirical criterion, its basis lies in the marked differences in the ultrastructure and chemical composition of the two main kinds of bacteria. These bacteria are distinguished from each other based on the presence or absence of an outer lipid membrane, which is a more reliable and fundamental characteristic of the bacterial cells.

    All gram-positive bacteria are bounded by a single unit lipid membrane; they generally contain a thick layer (20-80 nm) of peptidoglycan responsible for retaining the Gram-stain. A number of other bacteria which are bounded by a single membrane but stain gram-negative due to either lack of the peptidoglycan layer (viz., mycoplasmas) or their inability to retain the Gram-stain due to their cell wall composition, also show close relationship to the gram-positive bacteria. For the bacterial (prokaryotic) cells that are bounded by a single cell membrane the term "monoderm bacteria" or "monoderm prokaryotes" has been proposed. In contrast to gram-positive bacteria, all archetypical gram-negative bacteria are bounded by a cytoplasmic membrane as well as an outer cell membrane; they contain only a thin layer of peptidoglycan (2–3 nm) between these membranes. The presence of both inner and outer cell membranes forms and define the periplasmic space or periplasmic compartment. These bacterial cells with two membranes have been designated as diderm bacteria. The distinction between the monoderm and diderm prokaryotes is supported by conserved signature indels in a number of important proteins (viz. DnaK, GroEL).

    In diderm 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). Importantly, the periplasm is devoid of ATP.

2018c

• (Gene Ontology, 2018) ⇒ periplasmic space In: (1999-2016). the Gene Ontology Retrieved: 2018-04-29
  • QUOTE: Term Information

    Accession GO:0042597

    Name periplasmic space

    Ontology cellular_component

    Synonyms periplasm

    Alternate IDs GO:0005620

    Definition The region between the inner (cytoplasmic) and outer membrane (Gram-negative Bacteria) or cytoplasmic membrane and cell wall (Fungi and Gram-positive Bacteria). Source: GOC:go_curators, GOC:md

    Comment None

    History See term history for GO:0042597 at QuickGO

    Subset goslim_metagenomics, gosubset_prok, goslim_pir

    (...)

2009

• (Wikipedia, 2009) ⇒ http://en.wikipedia.org/wiki/Periplasm
  • The periplasmic space or periplasm is a space between the inner cytoplasmic membrane and external outer membrane of Gram-negative bacteria or the equivalent space between the cell membrane and cell wall in Gram-positive bacteria. It may constitute up to 40% of the total cell volume in Gram-negative species, and is drastically smaller in Gram-positive. [1]
  • The space contains a loose network of murein (peptidoglycan) chains, as well as a gel containing hydrolytic and degradative enzymes. [2] Other enzymes in the gel are involved in various biochemical pathways including peptidoglycan synthesis, electron transport, and alteration of substances toxic to the cell (xenobiotic metabolism). [3] In some species, the gel also contains beta-lactamase, an enzyme responsible for degrading penicillin. This can be of clinical importance when considering antibiotic resistance.

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