Lactococcal bacteriocins - mode of action and immunity
TL;DR: The lactococcal bacteriocins are hydrophobic cationic peptides, which form pores in the cytoplasmic membrane of sensitive cells.
About: This article is published in Trends in Microbiology.The article was published on 1995-08-01 and is currently open access. It has received 78 citations till now. The article focuses on the topics: Bacteriocin & Antimicrobial peptides.
Summary (2 min read)
Jump to: [Lactococcal bacteriocins: mode of action and immunitv] – [Mode of action of lantlbiotics: nisin] – [REVIEWS] – [Mode of action of non-Iantibiotics Diplococcin] – [Lactostrepcin 5] – [Lactococcins A and B] – [Nisin immunity and resistance] and [Conclusions and perspectives]
Lactococcal bacteriocins: mode of action and immunitv
- It is tempting to assume that different strains of a species produce these substances to enable them to compete for the same ecological niche.
- Class I bacteriocins, or lantibiotics, are small membrane-active peptides that contain the unusual amino acids lanthionine, P-methyllanthionine, dehydroalanine and dehydrobutyrine.
- All the lactococcal bacteriocins that have been thoroughly characterized so far belong to class I or II.
Mode of action of lantlbiotics: nisin
- Nisin is the only lantibiotic produced by L. luctis for which the mode of action has been studied.
- It is active against a broad spectrum of Gram-positive bacteria; Escherichia coli and other Gram-negative bacteria are only affected when their outer membranes are weakened or disrupted by treatment with EDTA or osmotic shock21,22, which makes their inner membrane accessible to the lantibiotic.
REVIEWS
- Nisin has a dual activity against spore-forming bacteria: it inhibits the outgrowth of spores and kills cells in the vegetative state.
- The 2,3_didehydroamino acid residues in nisin are thought to act against spores by interacting with the membrane sulfhydryl groups of germinating spores 23.
- It dissipates the membrane potential of whole cells, cytoplasmic membrane vesicles and artificial membrane vesicles ( liposomes)24125, indicating that the peptide does not require a specific receptor protein for activity or for membrane insertion.
- Membrane disruption is believed to result from the incorporation of nisin into the cytoplasmic membrane to form an ion channel or pore.
- This may account for the differences in sensitivity seen be-tween bacterial species or strains, as permeabilization only occurs in liposomes that contain zwitterionic phospholipids28T2p.
Mode of action of non-Iantibiotics Diplococcin
- The effect of purified diplococcin from L. lactis subsp.
- The addition of 8 arbitrary units of diplococcin to sensitive cells completely abolishes DNA and RNA synthesis within 2 min, which may partially interrupt protein synthesis.
- Small pores allow leakage of protons and other small ions only, whereas amino acids leak through larger pores.
- No receptor is required for nisin activity.
Lactostrepcin 5
- Lactostrepcin 5 (Las.5) and other lactostrepcins have a strong and rapid bactericidal effect on sensitive cells33; only Las5 has been characterized in detail.
- It inhibits uridine uptake and causes leakage of K+ ions and ATP from cells.
- Like diplococcin, Las5 inhibits DNA, RNA and protein synthesis, probably by the inhibition of transport of precursors required for macromolecular synthesis, energy depletion of the cell and/or leakage from the cell of small solutes that are required for various metabolic activities.
- Las5 is equally active against energized and energy-depleted cells33.
Lactococcins A and B
- They belong to a group of small, cationic hydrophobic peptides (including several lantibiotics) that permeabilize membranes28934"6.
- The mode of action of purified lactococcin A has been studied using whole cells of sensitive lactococcal strains and membrane vesicles made from such cells, and also using liposomes obtained from lactococcal phospholipids3'.
- Similar studies on whole cells have also been done using partially purified lactococcin B (Ref. 38) .
- These results indicate that both lactococcins form pores in the cytoplasmic membrane in a voltage-independent manner.
- Low concentrations of lactococcin B allow leakage of protons and ions, whereas ISO-fold more bacteriocin is needed for leakage of glutamate to occur38, which indicates that pores of different sizes can exist.
Nisin immunity and resistance
- There are several mechanisms by which bacteria protect themselves against nisin.
- Nisin resistance (Nis') is not genetically linked to nisin production.
- These results have been united in a model for LciA topology (Fig. 3b ).
- Residues 29-47 are considered to span the cytoplasmic membrane as an amphiphilic a helix by interacting with another transmembrane protein, possibly the lactococcin A receptor.
Conclusions and perspectives
- The past few years have seen significant progress in their understanding of nisin and the lactococcins.
- The structural and immunity genes and the genes encoding the secretion and post-translational modification machinery have been cloned, and the authors are now beginning to understand the modes of action of nisin and the lactococcins A and B, and the way in which the lactococcin A immunity protein LciA works.
- This knowledge, combined with structure-function studies of the bacteriocins, should allow the construction of molecules with enhanced or altered activities and broader specificities for use as, for example, food preservatives.
- A tropism for the mucous membranes of the human respiratory tract; indeed, the upper respiratory tract of humans is virtually the sole reservoir for this organism.
- Infection by H. in/kenzae illustrates the complex interplay that can occur between the host and the pathogen, in a relationship that does not always culminate in disease4.
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TL;DR: The growth parameters of the producer strain as well as the production kinetics and preliminary characterisation of the produced bacteriocin named enterocin 3915 found to be relatively heat-stable with a molecular mass of about 6.5 kDa.
Abstract: Different Enterococci, isolated from starters for the production of the traditional Bulgarian yellow cheese 'Kashkaval' were screened for bacteriocin production, and one of them, Enterococcus faecalis 3915 demonstrated bacteriocin activity. In this study, we investigated the growth parameters of the producer strain as well as the production kinetics and preliminary characterisation of the produced bacteriocin named enterocin 3915. For the growth modelling, the logistic model was used, while bacteriocin production was monitored. Experiments on inducibility were conducted, and strain was checked for the presence of plasmids. The peptide was crudely purified by ammonium sulphate precipitation followed by preparative PAGE. The approximate molecular mass was determined electrophoretically, and the activity was visualised by electrophoresis and agar overlay technique. It was found that E. faecalis 3915 produces a bacteriocin with constitutive synthesis and chromosomal localisation of its genetic determinants. The peptide revealed to be relatively heat-stable with a molecular mass of about 6.5 kDa. As E. faecalis 3915 originates from cheese starter it can be classified as generally recognised as safe (GRAS). The inhibitory activity of enterocin 3915 comprises commensals or pathogens, so properties generally accepted as probiotic could be attributed to the producer, and potential application in the dairy industry is not to be excluded.
6 citations
Cites background from "Lactococcal bacteriocins - mode of ..."
...These peptides are often cationic and amphiphilic or hydrophobic, and many of them kill bacteria by permeabilising the target cell membrane (Venema et al., 1995)....
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01 Sep 2020
TL;DR: Genes associated with the ability of probiotics to develop in the digestive tract of animals, the ability to attach to the intestinal walls, nutritional characteristics and antipathogenic activity, manifests in the synthesis of low and high molecular weight metabolites are found.
Abstract: The aim of the study is to search and systematize genes associated with the probiotic properties of strains of the genus Lactobacillus, which are symbionts of the gastrointestinal tract of animals. The following purpose were pursued in the study: to establish the molecular features of the probiotic properties of strains of the genus Lactobacillus; to find the genes associated with probiotic properties of Lactobacillus strains; to systematize the genes found according to the molecular characteristics of their products; to characterize these genes, evaluate perspectives of searching for new and using already found ones. Various genomic and proteomic databases were used to search for information on the genetics of probiotic strains. In the course of the study, genes that provide probiotic activity were found, characterized and systematized. These genes are associated with the ability of probiotics to develop in the digestive tract of animals, the ability to attach to the intestinal walls, nutritional characteristics and antipathogenic activity, which manifests in the synthesis of low and high molecular weight metabolites.
5 citations
01 Jan 2008
TL;DR: The potential application of nanotechnology methods for developing natural biopolymer-based biodegradable packaging materials, creating additional bioactive functions, might lead to dramatic changes in active food packaging as discussed by the authors.
Abstract: Publisher Summary Conventional food packaging focuses on the appearance, size, and integrity of the package in which food safety has been maintained by incorporating synthetic preservative agents into the food. Active packaging is an integral part of food safety providing not only an inert barrier to outside influences but also some desirable functions such as high quality and microbiological safety and longer product shelf-life. The preservatives, preferably from natural sources, can be incorporated into the packaging material or bound on the surface either permanently or temporarily where, in the latter case, the antioxidant and/or antimicrobial agents are slowly released onto the packed food during the shelf-life. The oxygen permeability of the packaging materials can alter the headspace oxygen concentration. A reduction in oxygen concentration in a package can inhibit oxidative reactions as well as the growth of certain microorganisms. The potential application of nanotechnology methods for developing natural biopolymer-based biodegradable packaging materials, creating additional bioactive functions, might lead to dramatic changes in active food packaging. Nano-materials are being developed with enhanced physical properties to ensure better protection of food. The specific design of nano-scale and microscale internal structures in edible films and coatings might create powerful protection.
5 citations
TL;DR: In this article, the inhibition spectrum of a bacteriocin produced by Lactobacillus buchneri, isolated from a Mexican sausage, against Listeria monocytogenes and several lactic acid bacteria, was studied.
Abstract: Bacteriocins are antimicrobial peptides acting on certain pathogens and spoilage microorganisms They have recently been considered as natural alternative to food preservatives The objective of this work was to study the inhibition spectrum of a bacteriocin produced by Lactobacillus buchneri, isolated from a Mexican sausage, against Listeria monocytogenes and several lactic acid bacteria, and the influence of several extrinsic parameters on bacteriocin activity Culture media (MRS or APT) had no significant effect on bacteriocin production (p 0001) Bacteriocin activity was also increased by 100% nitrogen atmosphere (180 AU/mL) as compared to N2/CO2 (50:50) (150 AU/mL) and 100% CO2 (60 AU/mL) Maximum activity occurred at the end of the exponential growth phase This bacteriocin inhibited some Listeria monocytogens strains and several lactic acid bacteria, mainly Lactobacillus sp
4 citations
Cites background from "Lactococcal bacteriocins - mode of ..."
...Venema et al.([39]) reported that N2 atmospheres promotes anaerobic conditions increasing bacteriocin stability due to the reducing environment....
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...These results were in agreement with those reported by De Vuyst and Vandamme[34] who found that N2 could promote bacteriocin production, whereas Venema et al.[39] reported that N2 atmospheres promotes anaerobic conditions increasing bacteriocin stability due to the reducing environment....
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01 Jan 1997
TL;DR: The results indicate that the model system may be a suitable means of estimating the growth of bacteria on minimally processed produce, packaged under modified atmospheres, and suggest that growth of the above pathogens may occur at 8°C, thereby imposing a safety hazard for these products.
Abstract: A solid surface model system was developed to study the effect of gas atmosphere composition on the growth of Aeromonas hydrophila. Yersinia enterocolitica, Listeria monocytogenes, and a cold tolerant strain of Bacillus cereus. The organisms were incubated on an agar surface at 8°C under either 1.5 or 21% 0 2 , combined with 0, 5, 20 or 50% C02 . The remainder of each atmosphere was made up to 100% with N2. Growth was evaluated on the basis of three parameters, namely maximum specific growth rate, maximum population density and lag time. In all instances the maximum specific growth rate decreased significantly with increasing C02 concentration. Prolonged lag times were observed only for Y. enterocolitica under 50% C02 / 21% 0 2 / 29% N2, while a strong reduction in the maximum population density was noted only for B. cereus at the highest level of C02. The 0 2 concentrations tested did not significantly affect maximum specific growth rates nor maximum population densities in any case. The results indicate that the model system may be a suitable means of estimating the growth of bacteria on minimally processed produce, packaged under modified atmospheres. Extrapolation of our results to modified atmosphere packaged fruits and vegetables using typical 0 2 concentrations of 1 to 5% and C02 concentrations of 5 to 10%, suggest that growth of the above pathogens may occur at 8°C, thereby imposing a safety hazard for these products.
4 citations
References
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TL;DR: The biochemical and genetic characteristics of these antimicrobial proteins are reviewed and common elements are discussed between the different classes of bacteriocins produced by these Gram-positive bacteria.
Abstract: Lactic acid bacteria produce a variety of bacteriocins that have recently come under detailed investigation. The biochemical and genetic characteristics of these antimicrobial proteins are reviewed and common elements are discussed between the different classes of bacteriocins produced by these Gram-positive bacteria.
2,013 citations
TL;DR: The range of inhibitory activity by bacteriocins of lactic acid bacteria can be either narrow, inhibiting only those strains that are closely related to the producer organism, or wide, inhibited a diverse group of Gram-positive microorganisms as mentioned in this paper.
1,754 citations
TL;DR: It is demonstrated that nisin is bactericidal to Salmonella species and that the observed inactivation can be demonstrated in other gram-negative bacteria.
Abstract: Nisin, produced by Lactococcus lactis subsp. lactis, has a broad spectrum of activity against gram-positive bacteria and is generally recognized as safe in the United States for use in selected pasteurized cheese spreads to control the outgrowth and toxin production of Clostridium botulinum. This study evaluated the inhibitory activity of nisin in combination with a chelating agent, disodium EDTA, against several Salmonella species and other selected gram-negative bacteria. After a 1-h exposure to 50 micrograms of nisin per ml and 20 mM disodium EDTA at 37 degrees C, a 3.2- to 6.9-log-cycle reduction in population was observed with the species tested. Treatment with disodium EDTA or nisin alone produced no significant inhibition (less than 1-log-cycle reduction) of the Salmonella and other gram-negative species tested. These results demonstrated that nisin is bactericidal to Salmonella species and that the observed inactivation can be demonstrated in other gram-negative bacteria. Applications involving the simultaneous treatment with nisin and chelating agents that alter the outer membrane may be of value in controlling food-borne salmonellae and other gram-negative bacteria.
586 citations
TL;DR: Transcription analyses of several L. lactis strains indicated that an expression product of the nisA gene, together with NisR, is required for the activation of nisinA transcription, indicating that NisI plays a role in the immunity mechanism.
Abstract: The nisin gene cluster nisABTCIPR of Lactococcus lactis, located on a 10-kbp DNA fragment of the nisin-sucrose transposon Tn5276, was characterized. This fragment was previously shown to direct nisin-A biosynthesis and to contain the nisP and nisR genes, encoding a nisin leader peptidase and a positive regulator, respectively [van der Meer, J. R., Polman, J., Beerthuyzen, M. M., Siezen, R. J., Kuipers, O. P. & de Vos, W. M. (1993) J. Bacteriol. 175, 2578–2588]. Further sequence analysis revealed the presence of four open-reading frames, nisB, nisT, nisC and nisI, downstream of the structural gene nisA. The nisT, nisC and nisI genes were subcloned and expressed individually in Escherichia coli, using the T7-RNA-polymerase system. This resulted in the production of radio-labelled proteins with sizes of 45 kDa (NisC) and 32 kDa (NisI). The nisT gene product was not detected, possibly because of protein instability. The deduced amino acid sequence of NisI contained a consensus Iipoprotein signal sequence, suggesting that this protein is a lipid-modified extracellular membrane-anchored protein. Expression of nisI in L. Iactis provided the cells with a significant level of protection against exogeneously added nisin, indicating that NisI plays a role in the immunity mechanism. In EDTA-treated E. coli cells, expression of nisI conferred up to a 170-fold increase in immunity against nisin A compared to controls. Moreover, a lactococcal strain deficient in nisin-A production, designated NZ9800, was created by gene replacement of nisA by a truncated nisA gene and was 10-fold less resistant to nisin A than the wild-type strain. A wild-type immunity level to nisin and production of nisin was obtained in strain NZ9800 harboring complementing nisA and nisZ plasmids. Transcription analyses of several L. IIactis strains indicated that an expression product of the nisA gene, together with NisR, is required for the activation of nisA transcription.
564 citations
TL;DR: The data suggest that the cytoplasmic membrane is the primary target and that membrane disruption accounts for the bactericidal action of nisin.
Abstract: The peptide antibiotic nisin was shown to cause a rapid efflux of amino acids and Rb+ from the cytoplasm of gram-positive bacteria (Staphylococcus cohnii 22, Bacillus subtilis W 23, Micrococcus luteus ATCC 4698, and Streptococcus zymogenes 24). It strongly decreased the membrane potential of cells as judged by the distribution of the lipophilic tetraphenylphosphonium cation. Ascorbate-phenazine methosulfate-driven transport of L-proline by cytoplasmic membrane vesicles was blocked after addition of nisin, and accumulated amino acids were released from the vesicles. Soybean phospholipid (asolectin) vesicles were not affected by nisin. The data suggest that the cytoplasmic membrane is the primary target and that membrane disruption accounts for the bactericidal action of nisin.
379 citations