Role of Porins in Sensitivity of
            <i>Escherichia coli</i>
            to Antibacterial Activity of the Lactoperoxidase Enzyme System

Supplementation of raw milk with 0.5% methylated soybean protein (MSP) or methylated chickpea protein (MCP) delayed its spoilage at room temperature (25C) and extended its technological validity up to 12 h instead of 6 h in case of the control. Titratable acidity and pH reached respective levels of 0.22 and 6.30 in raw milk provided with 0.5% esterified legume protein after 12 h of storage at room temperature against 0.49 and 4.64 in case of control. MSP (0.5%) delayed casein degradation to the 24th hour instead of 12 h in case of control and extended milk stability to heat and ethanol to 12 h instead of 6 h in case of control. Total mesophilic bacteria, Pseudomonas spp. and Enterobacteriaceae counts, in MSP‐ and MCP‐supplemented raw milk were lower by about 1.9–2.0 log as compared with control after 12 h of storage at room temperature. Practical Applications Extending the technological milk validity from 6 to 12 h will help avoid big losses of raw milk and enhance its chances to be incorporated into many dairy products while avoiding hygienic, chemical and technological deterioration.

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“…Some mutants of Escherichia coli with tolerance to LP‐s have been isolated (De Spiegeleer et al . ).…”

Section: Introductionmentioning

confidence: 97%

Extending the Technological Validity of Raw Buffalo Milk at Room Temperature by Esterified Legume Proteins

Osman

Mahgoub

El-Masry

et al. 2012

Journal of Food Processing and Preservation

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“…However, it soon emerged that bacteria are able to resist antibiotics in a number of ways123. One of their most efficient strategies involves the synthesis of enzymes that degrade the antibiotics.…”

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confidence: 99%

Insights into an evolutionary strategy leading to antibiotic resistance

Hou

Liu

Collyer

et al. 2017

Sci Rep

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Metallo-β-lactamases (MBLs) with activity towards a broad-spectrum of β-lactam antibiotics have become a major threat to public health, not least due to their ability to rapidly adapt their substrate preference. In this study, the capability of the MBL AIM-1 to evade antibiotic pressure by introducing specific mutations was probed by two alternative methods, i.e. site-saturation mutagenesis (SSM) of active site residues and in vitro evolution. Both approaches demonstrated that a single mutation in AIM-1 can greatly enhance a pathogen’s resistance towards broad spectrum antibiotics without significantly compromising the catalytic efficiency of the enzyme. Importantly, the evolution experiments demonstrated that relevant amino acids are not necessarily in close proximity to the catalytic centre of the enzyme. This observation is a powerful demonstration that MBLs have a diverse array of possibilities to adapt to new selection pressures, avenues that cannot easily be predicted from a crystal structure alone.

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“…35) Lactoperoxidase also contributes to the antimicrobial defense in secretory fluids. 36,37) The hypothesis that salivary SCN − can protect the stomach from OH radicals formed by ascorbic acid/H 2 O 2 /Fe(II) systems under acidic conditions was reported. 38) Thus the change in SCN − concentration may have a significant effect not only on the oral cavity, but also on other sites in the body.…”

Section: Discussionmentioning

confidence: 99%

Effect of Psychologic Stress on Peroxidase and Thiocyanate Levels in Human Saliva Detected by Ultraweak Chemiluminescence

Goi

Takagi

Hirai

et al. 2007

JOURNAL OF HEALTH SCIENCE

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Saliva sampling has the advantage of being noninvasive and stress free. Based on a recent study, salivary ultraweak chemiluminescence (UCL) is a new biomarker of psychologic stress. However, it is not clear what causes changes in the UCL level and whether the change is biologically significant. We investigated the candidates for salivary UCL induced by psychological stressors and discuss the physiologic function of these candidates. Volunteers completed a questionnaire and then performed the Kraepelin test. Saliva was sampled just before, immediately after, and 30 min after the stress exposure. The UCL of saliva significantly increased just after stress exposure (1.56-fold) and returned to prestress levels after 30 min. The concentration of secretory immunoglobulin A also increased significantly and the change in both biomarkers was rapid. Similar significant changes were observed in salivary peroxidase activity and the concentration of thiocyanate (SCN − ). On the other hand, the levels of amylase activity did not significantly increase and the concentration of cortisol increased slowly. Moreover, in the reconstitution experiment, UCL was generated at the same level by a mixture of peroxidase and SCN − at physiologic concentrations. In conclusion, we determined that the Kraepelin test as a mental arithmetic task elicited a significant response in the body and this response can be calculated using salivary UCL. Furthermore, SCN − and peroxidase in the saliva play a key role in salivary UCL.

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Role of Porins in Sensitivity of Escherichia coli to Antibacterial Activity of the Lactoperoxidase Enzyme System

Cited by 29 publications

References 51 publications

Extending the Technological Validity of Raw Buffalo Milk at Room Temperature by Esterified Legume Proteins

Extending the Technological Validity of Raw Buffalo Milk at Room Temperature by Esterified Legume Proteins

Insights into an evolutionary strategy leading to antibiotic resistance

Effect of Psychologic Stress on Peroxidase and Thiocyanate Levels in Human Saliva Detected by Ultraweak Chemiluminescence

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