The Bacterial Cell Surface

Hammond, Stephen M.; Lambert, Peter A.; Rycroft, Andrew N.

doi:10.1007/978-1-4757-0187-6

Cited by 13 publications

(13 citation statements)

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“…But interestingly, activity changes induced in the Gram-positive bacteria S. aureus, mostly parallel haemolytic activity leading to the suggestion that hydrophobic peptide-membrane interactions play a decisive role. However, in contrast to red blood cells, Gram-positive bacterial membranes contain negatively charged compounds such as teichoic and teichuroic acids and the carboxyl groups of amino acids found in the peptidoglycan layer [29]. Thus, the low MIC values against S. aureus compared to EC50 could be explained in part by the demonstrated increased peptide affinity to negatively charged surfaces [14,15].…”

Section: Discussionmentioning

confidence: 99%

Hydrophobicity, hydrophobic moment and angle subtended by charged residues modulate antibacterial and haemolytic activity of amphipathic helical peptides

Dathe¹,

Wieprecht²,

Nikolenko³

et al. 1997

FEBS Letters

368

270

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The hydrophobicity (H), hydrophobic moment (|i) and the angle subtended by the positively charged helix face () of a set of model and magainin 2 amide peptides with conserved charge and helix propensity have been shown to be effective modulators of antibacterial and haemolytic activity. Except peptides of low hydrophobicity which are inactive, changing the parameters has little influence on the activity against Gramnegative bacteria, thus revealing the dominance of electrostatic interactions for the effect. However, the increase of H, |i and <5> substantially enhances haemolytic and Gram-positive antibacterial activity and is related to a reduction of peptide specificity for Gram-negative bacteria.

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Section: Discussionmentioning

confidence: 99%

Hydrophobicity, hydrophobic moment and angle subtended by charged residues modulate antibacterial and haemolytic activity of amphipathic helical peptides

Dathe¹,

Wieprecht²,

Nikolenko³

et al. 1997

FEBS Letters

368

270

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“…The outer membrane of gram‐negative bacteria is damaged when cells are exposed to heating. It was observed that about 20% of the lipopolysaccharide was released into the heating medium when cells of E. coli K‐12 were subjected to mild heating (48C) for 1 h (Hammond et al. 1984).…”

Section: Discussionmentioning

confidence: 99%

CORRELATION BETWEEN CITRIC ACID,THYMUS VULGARISEXTRACT AND NaCl, AND HEAT SENSITIVITY AND CASEINASE PRODUCTION BYAEROMONAS CAVIAEANDA. SOBRIA

Abu-Ghazaleh

2008

Journal of Food Processing and Preservation

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The effects of citric acid, Thymus vulgaris extract and NaCl on the heat sensitivity of Aeromonas spp. were examined in three different situations in this study. First, the effects of pretreatment with nutrient broth plus 0.03% citric acid, nutrient broth plus 0.3% T. vulgaris extract, nutrient broth plus 2.5% NaCl or nutrient broth plus 3% NaCl on the survival and caseinase production by heated A. caviae 166 and A. sobria 74 were investigated. Pretreatment of Aeromonas spp. with these preservatives for 1 or 6 days significantly increased their resistance to subsequent heating at 54C. However, pretreatment of Aeromonas strains with nutrient broth plus 2.5% NaCl or nutrient broth plus 3% NaCl before heating at 54C significantly (P < 0.05) decreased the production of caseinase by the heated cells. Second, the effect of post‐treatment with preservatives after heating of Aeromonas strains was examined. Post‐treatment of Aeromonas strains with the tested preservatives for 7 days after heating at 54C for 20 min prevented a complete recovery of cells and decreased the caseinase production compared with Aeromonas cells that were incubated in nutrient broth alone for 7 days after heating at 54C. Third, the effect of the type of the heating menstruum on the heat sensitivity of Aeromonas strains was investigated in this study. Heating in NaCl (0.85%) containing citric acid (0.03%) was the most effective treatment in killing Aeromonas spp. Heating in NaCl (0.85%) containing T. vulgaris extract (0.3%) or in NaCl (3.85%) slightly increased the resistance of cells to heat. PRACTICAL APPLICATIONS The results obtained in this study can be applied in the food industry, where combination of mild heat treatment and addition of low doses of chemical preservatives to food is nowadays frequently used. This study determined the heat sensitivity and caseinase production by A. caviae and A. sobria at three different conditions that may be encountered during processing of food industrially or at home. Firstly, the effect of pretreatment with some preservatives on the heat sensitivity and caseinase production by the tested Aeromonas. spp. was studied. Secondly, the effect of post‐treatment with preservatives on growth and caseinase production by the heated (54C) Aeromonas cells was investigated. Thirdly, effect of presence of preservatives in the heating menstruum on the heat sensitivity of Aeromonas spp. was studied.

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“…The outer membrane (OM) serves as a barrier to hydrophobic molecules, making gram-negative bacteria resistant to antibiotics hydrophobic in nature (32,33). The surface of gram-positive bacteria would have large net negative charge owing to the presence of teichoic and teichuronic acids and carboxyl groups of amino acids in the peptidoglycan (34). Gram-positive bacteria do not have a lipopolysaccharide layer.…”

Section: Discussionmentioning

confidence: 99%

Structural and charge requirements for antimicrobial and hemolytic activity in the peptide PKLLETFLSKWIG, corresponding to the hydrophobic region of the antimicrobial protein bovine seminalplasmin

Sitaram

Subbalakshmi

Nagaraj

1995

International Journal of Peptide and Protein Research

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Several analogs of the 13-residue antimicrobial and hemolytic peptide PKLLETFLSKWIG (SPF), which is the most hydrophobic region of the 47-residue antimicrobial protein seminalplasmin [ Sitaram, N. & Nagaraj, R. (1990) J. Biol. Chem. 265, 10438-104423 have been synthesized. The antimicrobial and hemolytic properties of the peptides were investigated with a view to gain an insight into the structural and charge requirements for these activities of SPF. Peptides in which E was replaced by K exhibited considerably improved antimicrobial activity with no concomitant increase in hemolytic activity. A peptide in which the aromatic amino acids were replaced by leucine exhibited antimicrobial activity like those of the peptides which had aromatic amino acids. Interchange in the positions of E and K and total replacement of K by E resulted in complete loss of activity. The peptides having antimicrobial activities showed appreciable helical content in a hydrophobic environment, whereas inactive peptides did not. Thus, by suitable 'engineering' the biological activity of a short 13-residue peptide can be altered to yield peptides specifically having only antimicrobial activity with increased potency. 0 Munksgaard 1995.

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The Bacterial Cell Surface

Cited by 13 publications

References 0 publications

Hydrophobicity, hydrophobic moment and angle subtended by charged residues modulate antibacterial and haemolytic activity of amphipathic helical peptides

Hydrophobicity, hydrophobic moment and angle subtended by charged residues modulate antibacterial and haemolytic activity of amphipathic helical peptides

CORRELATION BETWEEN CITRIC ACID,THYMUS VULGARISEXTRACT AND NaCl, AND HEAT SENSITIVITY AND CASEINASE PRODUCTION BYAEROMONAS CAVIAEANDA. SOBRIA

Structural and charge requirements for antimicrobial and hemolytic activity in the peptide PKLLETFLSKWIG, corresponding to the hydrophobic region of the antimicrobial protein bovine seminalplasmin

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