Bovine Serum Does Not Inhibit Escherichia Coli Growth.

Bovine Serum Does Not Inhibit Escherichia coli   growth.








By:
Laurence Bernard







Lab 1

Term Project

Biology 106

Will Hunter

April 5th, 2007



















Title: Bovine Serum Does Not inhibit Escherichia coli   growth.


Abstract:  
Innate immunity has a huge impact on our resistance to bacteria and our health. The purpose of this research is to determine whether bovine serum shows antibacterial activity on bacteria, to better understand the mechanism of immunity. Bovine serum, NaCl solution at 9g./L, the blood salt concentration,   and distilled water were tested on nutrient agar containing the bacterium Escherichia coli.   The results of the experiment show that bovine serum doesn’t inhibit   E. coli growth, concluding that the cow’s immune system is inefficient at killing bacteria at a large concentration.


Introduction:  
Being surrounded by bacteria, our immune system had to develop a method to protect itself from the pathogen strains. Antimicrobial peptides are the key to innate immunity (Chang et al. 2005) (Lysenko et al. 2002). About 500 antimicrobial peptides are repertoried, as in 2002 (Zasloff 2002). They are usually found in tears, breast milk, seminal and vaginal fluids and on the skin (Sigurdardottir et al. 2006). In the serum, they are carried on the platelets and the neutrophil granulocytes (Tang et   al. 2002). Made of defensins, cecropins and cathelicidins, they behave, once isolated and purified, as broad-spectrum antibiotics and neutralize bacterial lipopolysaccharides (Sigurdardottir et al. 2006) (Vorland et al. 1999).. Cathelicidins are found in human, bovine, porcine, rabbit, mouse and ovine tissues (Wang et al. 1998). The cathelicidin α-helical LL-37 is found on human and bovine epithelia and neutrophils granulocytes (Peschel 2002). An other peptide, Histidine-rich glycoprotein (HRGP), is also effective, at a low pH and in presence of Zn2- at inhibiting Escherichia coli... [continues]

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