Antimicrobials lysozyme

FIGURE 61.5 Schematic representation of antimicrobial active-packaging. Micro-organisms hydrolyze starch-based particles, causing release of the antimicrobial lysozyme, resulting in inhibition of microbial growth. (From De Jong, A.R. et al.. Food Addit. Contain., 22(10), 975, 2005.)... 

Research is under way to investigate the potential to develop the natural antimicrobial system present in milk, such as the lysozyme, lactoferrin,... 

Antimicrobial activity lysozyme, lactoperoxidase (which is exploited as a component of the lactoperoxidase - H202 - thiocyanate system for the cold pasteurization of milk). 

Nakamura, S., Kato, A., and Kobayashi, K. 1991. New antimicrobial characteristics of lysozyme-dextran conjugate. J. Agric. Food Chem. 39, 647-650. 

Lysozyme 0.0004 0.0004 Antimicrobial, synergistic effect with Shah (2000)... 

Lysozyme (LZM) is a potent antibacterial enzyme acting against a range of bacteria, especially Gram-positive, but due to its low concentration in bovine milk (in contrast to human milk), LZM may not contribute significantly to the overall antimicrobial properties of cow s milk and colostrum. However, LZM is known to add to the antimicrobial activity of LF and specific antibodies (Reiter, 1985 IDF, 1991 Shah, 2000). 

Lysozyme Obtained from extracts of purified chicken egg whites. Generally prepared and used in the hydrochloride form as a white powder. Major active principle lysozyme. Typical application used as an antimicrobial in food processing. 

Paneth cells contribute to the maintenance of the gastrointestinal barrier, by secreting a number of antimicrobial molecules (alpha-defensins or cryptidins), as well as lysozyme and phospholipase A2. Their location, adjacent to crypt stem cells, suggests they have a role in defending epithelial cell renewal. 

The only way for microbes to enter a healthy plant is via the stomata or at sites of injury, inflicted by herbivory, wind, or other accidents. At the site of wounding, plants often accumulate suberin, lignin, callose, gums, or other resinous substances which close off the respective areas (4.17). In addition, antimicrobial agents are produced such as lysozyme and chitinase, lytic enzymes stored in the vacuole which can degrade bacterial and fungal cell walls, protease inhibitors which can inhibit microbial proteases, or secondary metabolites with antimicrobial activity. 

The interaction between an antimicrobial and a pathogen in the laboratory does not take normal host defense systems into account. Humoral and cell-mediated immune systems play a major role in pathogen eradication their contribution is underestimated in susceptibility reports. Antimicrobial agents act in concert with endogenous microbial inhibitors such as immunoglobulins, T lymphocytes, phagocytes, complement components, lactoferrin, lactoperoxidase and lysozymes. 

Lysozyme, which makes up 3.5% of the total egg white proteins and can be easily separated by ion-exchange techniques (Lesnierowski and Kijowski, 2001), is recognized as a safe, antimicrobial agent to be used for food preservation. It is stable up to about 100°C, has maximum activity at a pH range of 5.3-6.4, and inhibits several pathogenic bacteria, including Listeria monocytogenes, Clostridium botulinum, Yersinia enterocolitica, and Campylobacter jejuni (Kijowski and Lesnierowski, 1999). 

A study was carried out to investigate the feasibility of incorporating lysozyme, an antimicrobial enzyme into polymers that are approved for food contact use, and to determine if they would be effective against microorganisms in liquid media Hen egg white lysozyme was immobilised on PVOH beads, nylon 66 pellets and cellulose triacetate films, and activity yields for each are discussed. 26 refs. 

The shortest peptide that has been shown to interact with the HR-N trimer is HL9 (39), a nine-residue peptide derived from human lysozyme that potently inhibits HIV-1 syncytia formation in cell culture with an EC50 of 50 nM [144,145]. HL9 (39) contains two tryptophan residues separated by two amino acids that complement the hydrophobic pocket formed by the HR-N N17 fragment [142]. However, HL9 (39) is not completely specific for HIV-1, since it also exhibits antimicrobial activity [146]. 

---