Ilya Ilyich Mechnikov and his Discovery of Phagocytosis

Ilya Ilyich Mechnikov was a Russian zoologist best known for his pioneering research of the immune system. He was born on May 16, 1845, in a village near near Kharkov (now Kharkiv in Ukraine), Russian Empire. He was the youngest of five children of Ilya Ivanovich Mechnikov, an officer of the Imperial Guard. Ilya Ilyich Mechnikov went to school in Kharkov and even being a little boy, he was passionately interested in natural history, botany and geology. When he left school he went to the University of Kharkov to study natural sciences, and worked there so hard that he was able to complete the four year course in two years. Then, he continued his education in Germany. Later, he returned back to Russia. When he was twenty-two Mechnikov was appointed a docent at the newly established Imperial Novorossiya University (now Odessa University). Only twenty-two years of age, he was younger than his students. In 1870 he was appointed a Professor of Zoology and Comparative Anatomy.

Mechnikov became interested in the study of microbes, and especially the immune system. He discovered phagacytosis after experimenting on the larvae of starfish. In 1882 he first demonstrated the process when he pinned small thorns into starfish larvae, and he found unusual cells surrounding the thorns. The thorns were from a tangerine tree. He realized that in animals which have blood, the white blood cells gather at the site of inflammation, and he hypothesised that this could be the process by which bacteria were attacked and killed by the white blood cells. He discussed his hypothesis with Carl Friedrich Wilhelm Claus, Professor of Zoology at the University of Vienna, who suggested him the term "phagocyte" for a cell which can surround and kill pathogens. He delivered his findings at Odessa University in 1883.

His theory, that certain white blood cells could engulf and destroy harmful bodies such as bacteria, were met with scepticism from leading specialists including Louis Pasteur, Behring and others. At the time most bacteriologists believed that white blood cells ingested pathogens and then spread them further through the body.

He and Paul Ehrlich were awarded the 1908 Nobel Prize in Physiology or Medicine "in recognition of their work on immunity".

Mechnikov also developed a theory that aging is caused by toxic bacteria in the gut and that lacic acid could prolong life. Based on this theory, he drank sour milk every day. He wrote The Prolongation of Life: Optimistic Studies, in which he espoused the potential life-lengthening properties of lactic acid bacteria. He attributed the longevity of Bulgarian peasants to their yogurt consumption. This later inspired Japanese scientist Minoru Shirota to begin investigating a causal relationship between bacteria and good intestinal health, which eventually led to the worldwide marketing of different fermented milk drinks, or probiotics.

Mechnikov died in 1916 in Paris of heart failure.

Exercise 6. Answer the questions:

1. What is Ilya Ilyich Mechnikov best known for?

2. What was he interested in when he was a little boy?

3. Where did Ilya Ilyich Mechnikov study?

4. How did Mechnikov discover phagocytosis?

5. What were I.I. Mechnicov and Paul Ehrlich awarded a Nobel Prize for?

6. What theory about aging did Mechnikov develop?

7. What led to the worldwide marketing of different ferented milk drinks, or probiotics?

8. What did Mechnikov die of?

Exercise 7. Find corresponding equivalents in the text:

Вивчати природні науки; закінчити чотирьохрічний курс; продовжити освіту; бути призначеним доцентом; зацікавитися вивченням мікробів; личинки морської зірки; місце запалення; поглинати і знищувати; нападати на бактерії; запропонувати термін; бути нагородженим Нобелевською премією; викликати старіння; молочна кислота; продовжувати життя; споживання йогурту; здоров’я кишечнику; кисломолочні напої; серцева недостатність.

Exercise 8. Match the words with their definitions:

1. immune system 2. phagocytosis 3. phagocyte 4. pathogen 5. aging 6. lactic acid		a) an agent that causes a disease, especially a virus, bacterium or fungus; b) an organic acid, produced when milk sours c) the body’s system of defense against infective organisms or other foreign bodies invading the body d) a cell, such as a white blood cell, that engulfs and absorbs waste material, harmful microorganisms, or other foreign bodies in the bloodstream and tissues e) the process of growing old f) a process, by which a cell, such as a white blood cell, ingests and absorbs waste material, harmful microorganisms, or other foreign bodies in the bloodstream and tissues
1.	2.		3.	4.	5.	6.

Exercise 9. Fill in the gaps with prepositions from the table below:

In; for; of; for; in; at; by; after

1. He is best known … his research of the immune system.

2. He was able to complete the four year course… two years.

3. He discovered phagocytosis … experimenting on the larvae of starfish.

4. White blood cells gather … the site of inflammation

5. The bacteria were attacked and killed … the white blood cells.

6. Carl Friedrich Wilhelm Claus suggested him the term "phagocyte" …a cell which can surround and kill pathogens.

7. I.I. Mechnikov and Paul Ehrlich were awarded the 1908 Nobel Prize in Physiology or Medicine "… recognition of their work on immunity".

8. Mechnikov died … heart failure.

Exercise 10. Make the following active sentences passive, pay attention to the tense forms:

For example: White blood cells ingest harmful microorganisms. – Harmful microorganisms are ingested by white blood cells.

1. He completed the course in two years.

2. They appointed him a docent at the newly established Imperial Novorossiya University.

3. We call this process phagocytosis.

4. We will discuss it next time.

5. They have just translated the text.

6. White blood cells attack and kill bacteria.

7. They met the theory with skepticism.

8. Toxic bacteria in the gut cause aging.

Exercise 11. Put questions to the underlined words:

1. He was born on May 16, 1845.

2. He went to the University of Kharkov to study natural sciences.

3. In 1870 he was appointed a Professor of Zoology and Comparative Anatomy.

4. He discovered phagocytosis after experimenting on the larvae of starfish.

5. The white blood cells gather at the site of inflammation.

6. He and Paul Ehrlich were awarded the 1908 Nobel Prize in Physiology or Medicine.

7. He attributed the longevity of Bulgarian peasants to their yogurt consumption. 

8. Mechnikov died in 1916 in Paris of heart failure.

Exercise 12. Put the verbs in brackets into the correct form:

At St. Petersburg he (to meet) his first wife, Ludmilla Feodorovitch, who (to suffer) from tuberculosis so severe that she had to be carried to church in a chair for the wedding. For five years Mechnikov (to do) all he could to save her life, but she (to die) on April 20, 1873. Broken by this loss, troubled by weak eyesight and heart troubles and by difficulties in the University, Mechnikov (to become) at this time, so pessimistic that he (to try) to take his own life by swallowing a large dose of opium; but, fortunately for himself and for the world, he (not to die). It was in Odessa, in fact, that he (to meet) his second wife, Olga, whom he (to marry) in 1875. In 1880 his second wife (to have) a severe attack of typhoid fever (черевний тиф), but, fortunately, she (to recover).

Exercise 13. Use the plan to tell about I.I. Mechnikov:

Plan:

1. Date and place of birth.

2. Early childhood interests.

3. Education.

4. Work.

5. Discovery of phagocytosis.

6. End of life.

Exercise 14. Put the sentences into the correct order to tell about phagocytosis:

__It happened when he was experimenting on the larvae of starfish.

__Phagocytosis was discovered by I.I. Mechnikov.

__He realized then that in animals which have blood, the white blood cells gather at the site of inflammation.

__Phagocytosis is a process, by which a cell, such as a white blood cell, ingests and absorbs waste material, harmful microorganisms, or other foreign bodies in the bloodstream and tissues.

__So, he hypothesised that this could be the process by which bacteria were attacked and killed by the white blood cells.