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Flowering and vegetative growth of olive tree submitted to pruning and paclobutrazol application
Long-term survival in advanced non-squamous NSCLC patients treated with first-line bevacizumab-based therapy
Antimicrobial peptides produced by bacteria: The bacteriocins
Bacteriocins are the subset of antimicrobial peptides (AMPs) produced
by bacteria. They are small amphipathic peptides that interact with bacterial
membranes leading to cell death. Most of the best known are produced by lactic
acid bacteria used as food fermentation starters, because of their potential use as
food preservatives. Bacteriocins are divided into two groups: lantibiotics that present posttranslational condensation rings and unmodified peptides. The first are
subdivided into elongated versus globular lantibiotics, while four subgroups are
recognized among unmodified bacteriocins. The genetic organization is in clusters
that may reside into plasmids or transposons, formed by the structural gene, the
export and immunity determinants, the quorum sensing governing production and
any modification genes. Bacteriocins are active at extremely low concentrations
(nM range) due to a dual mode of action: (a) binding to the membrane phospholipids and (b) specific recognition of surface components, both of which collaborate
in pore formation. Development of resistance to bacteriocins is very infrequent due
to the presence of two targets and is usually due to unspecific modifications of the
cell envelope. Bacteriocins are used as food preservatives, either after total or partial
purification or as extracts of producing bacteria. In situ production is also used, with
the advantage of producing early lysis of the starter bacteria and ripening acceleration of the fermented product. They may also form part of hurdle technologies
and be incorporated into packaging systems to allow extended liberation. Medical
and veterinary applications are in their infancy but good results have been obtained
against infection by Gram-positive bacteria and Helicobacter pylori.Peer reviewe