Fleming’s shyness, his being “not a great lecturer,” as acknowledged by Allison, may partly account for the poor reception received at the first reading of the initial paper describing lysozyme. At this presentation in December 1921 held at the Medical Research Club, an exclusive audience of the leading medical practitioners, no questions were asked1. There was no resulting discussion. This was a sure sign that the work was considered irrelevant, likely due to its lack of efficacy against human pathogens. What wasn’t appreciated by the audience is that the reason for this inefficacy was precisely borne out of the body’s existing use of lysozyme. The remaining bacteria capable of evading lysozyme are then the ones that could affect us.
Work continued despite the poor initial reception, with 1922 publishing the first two papers describing lysozyme and the earliest findings around its capacity to kill bacteria.
Blood, spit, tears, and eggs
Fleming’s first paper set out the primary findings of the discovered properties of lysozyme, beginning with a recapitulation of its chance discovery in nasal mucus2. Through an elegant series of increasingly complex experiments, mucus, tears, and sputum (spit) were demonstrated to possess bactericidal activity.
One notable example used a cup made of agar (a jelly-like substance extracted from seaweed) to hold tears, onto which further layers of agar were added. These layers, acting as a physical filter, showed the ability of lysozyme to diffuse through, dissolving the thick coat of bacteria grown above (Figure 1). This experiment co-incidentally resembles a fried egg; the centrally embedded cup of tears resulted in destruction of bacteria in its vicinity.
Figure 2 demonstrates lysozyme’s activity against streptococci. On the upper half of the agar plate, we see a thick ‘lawn’ of bacterial growth, with bacterial colonies expanding to such an extent that they are inseparable from one another. On the lower half, tears diluted 100-fold were added to the dish. Here we see a dramatic reduction in bacterial growth, with individual colonies identifiable, showing the potency of lysozyme in tears.
While tears diluted to 1% concentration retained their capability of killing bacteria, egg-white still functioned after 1 in 50 million dilutions. Put another way, that is the same as if you were to divide one large beer (500ml) across 500,000 standard kegs (50l each).
Egg Lysozyme: extreme stability
In the paper that followed, the examination of eggs and their lysozyme content continued3. Here, the eggs of the pike caught at Fleming’s country house were put to the test1. These fish eggs were first dehydrated by immersion in acetone for 24 hours, then subjected to three months of immersion in a range of harsh chemicals and solvents including chloroform and xylene (Figure 3).
Remarkably, once embedded into an agar dish with a thick coating of bacteria, the egg’s lysozyme was found to still be active! The pike eggs, appearing as small black dots, cleared the bacteria in their vicinity (Figure 3), revealing the incredible stability of lysozyme.
- 1. Allison VD. Personal recollections of Sir Almroth Wright and Sir Alexander Fleming. Ulster Med J. 1974;43(2):89-98.
- 2. Fleming A. On A Remarkable Bacteriolytic Element found in Tissues and Secretions. Proc. Royal Soc. B 1922
- 3. Fleming A & Allison VD. Observations on a Bacteriolytic Substance (“Lysozyme”) found in Secretions and Tissues. Br J Exp Path. 1922
100 years of Lysozyme
2022 marks 100 years since news of Lysozyme’s discovery reached the Royal Society. Let us take you on the journey of this 100-year story:
Episode III Instalment 3
Lysozyme leads the way for DeepMind’s AlphaFold
Lysozyme contributed directly to our understanding of the structure-function relationship of proteins. It was the first solved structure that established the concept that the 3D shape of a protein[...]
Episode I Instalment 1
A beginning for Lysozyme
Bioseutica® group has been producing lysozyme from hen egg-white since the 1950s, a history spanning nearly 75 years. But lysozyme’s story doesn’t begin with us. For that, we must look back to the earliest human use of egg-white[...]
Episode I Instalment 2
Thus ended the collection of tears
The second installment of our 100 Years of Lysozyme series is now live. This week we discover how the abundance of Lysozyme in eggs was first discovered (hint: it wasn’t in the supermarket)[...]
Episode I Instalment 3
Not a great lecturer
Fleming’s shyness, his being “not a great lecturer” as acknowledged by Allison, may in part account for the poor reception received at the first reading of the initial paper describing lysozyme[...]
Episode I Instalment 4
Try £ 3
From 3p for tears to £3 for Picassos; in this installment, we uncover how Alexander Fleming’s eye and contributions had an immeasurable impact on medicine and science in the 20th century[...]
Episode II Instalment 1
A Tradition of Innovation
The aftermath of the war has left Italy economically devastated like the rest of the European countries. In Milan, another Ferrari begins production, but this time of Penicillin.[...]
Episode II Instalment 2
A Tradition of Innovation 2
The death of their first trial patient through the insufficient supply of Penicillin drove Florey, Chain, and their research assistant Heatley forward with inspired momentum.[...]
Episode II Instalment 3
A Tradition of Innovation 3
24th May 1947 saw the establishment of SPA (Società Prodotti Antibiotici) by Pharmacologist Dr. Rodolfo Ferrari and microbiologist Carlo Callerio. Now Italy had its own, domestic Penicillin[...]
Episode III Instalment 1
More than an antimicrobial
To most of us, if at least those reading, I hope, Lysozyme is best known as a potent, natural antimicrobial. This is evidently its primary purpose for the hen's egg, making[...]
Episode III Instalment 2
Finding the structure
Sir. William Bragg and Sir. Lawrence Bragg shared the Nobel Prize in 1915 for their work on analyzing crystal structures using X-Rays. This award is notable not only as it was the first and [...]