Introduction to Cell Biology

1.Aims and scopes of cytology, histology and embryology

2.Brief historical review

3.Microscopy and microscope types

4.Methods for microscopic observations

5.General principles of cytological and histological techniques

Prof. Dr. Nikolai Lazarov

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Cytology – now Cell Biology:(Gr. κύτος, kytos, a hollow + logos, study)

Objective of cytology, histology and embryology

Histology: (Gr. ἱστός, histos, web or tissue + logos)

general histology

special histology = microscopic anatomy of organs

Embryology: (Gr. έμβρυον, embryon + logos)

general embryology (embryogenesis)

special embryology (organogenesis)

Prof. Dr. Nikolai Lazarov

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History of cytology and histology

Period of observations (1590-1839)

Robert Hooke, 1665

Antony van Leeuwenhoek, 1678

Period of generalization (1839-)

Cell theory: Schleiden and Schwann (1838-1839)

Omnis cellula e cellula: Rudolf Virchow(1852)

Omnis nucleusе nucleo:Walther Flemming (1860)

Drawing of the structure of cork by Robert Hook

Period of the study of the cell structure

Period of cell and molecular biology –

20th century

biochemical cytology

cytogenetics

cytophysiology

molecular biology

cellular ecology

Prof. Dr. Nikolai Lazarov

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History of cytology and histology

Prof. Dr. Nikolai Lazarov

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History of light microscopy

NB: the invention of the compound microscope is credited to the Dutch spectacle maker, Zacharias Janssen, around the year 1590

Prof. Dr. Nikolai Lazarov

Émile DUCLAUX METCHNIKOFF Émile ROUX

Albert CALMETTE Jules BORDET

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Prof. Dr. Nikolai Lazarov

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Microscopy

Microscope types:

light (optical) microscope

phase contrast microscope

interference microscope

differential interference microscopy (DIC)

fluorescence microscope

polarizing microscope

confocal laser scanning microscope

electron microscope (EM)

transmission EM (TEM)

scanning EM (SEM)

scanning tunneling microscope (STM)

atomic force microscope

Prof. Dr. Nikolai Lazarov

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Light microscope

Mechanical part:

stand (arm&base)

objective holder (stage)

tube

Optical part:

ocular lens (eyepiece)

objective lens – types

condenser

Illumination part:

illumination source (mirror or light)

filters

Ernst Abbe(1840-1905)

Carl Zeiss(1816-1888)

NB: Zeiss made contributions to lens manufacturing that have aided the modern production of lenses while Abbe created the mathematical foundation of microscope design

Prof. Dr. Nikolai Lazarov

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Light microscopy

NB: Ernst Abbe developed a mathematical description for the resolution limit of the microscope

1010

Resolving power

Prof. Dr. Nikolai Lazarov

Prof. Dr. Nikolai Lazarov

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Frederik Zernicke(1888 – 1966)Nobel Prize in Physics, 1953

does not require staining to view the slide

possible to study living cells and the cell cycle

Phase contrast microscope

Prof. Dr. Nikolai Lazarov

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А. Lebedeff, 1930 –designed and built the first interference microscope useful for assessingsurface properties of cellsand other biologic objects

Interference microscope

Prof. Dr. Nikolai Lazarov

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Polarizing microscope

designed to observe specimens that are visible primarily due to their optically anisotropic character allows tissue structures containing oriented molecules (such as cellulose, collagen, microtubules, and microfilaments) to be recognized

two filters – polarizer and analyzer

Prof. Dr. Nikolai Lazarov

Albert H. Coons

(1912 – 1978)

Fluorescence microscope

used to display naturally occurring fluorescent (autofluorescent) molecules – neurotransmitters, vitamin A

the immunohistochemical techniques for labeling antibodies were developed in the early 1940s by Albert H. Coons

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Prof. Dr. Nikolai Lazarov

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Confocal laser scanning microscope

a technique for obtaining high-resolution optical images with depthselectivity and reconstruct them into a three-dimensional image

Marvin Minsky(1926 – 2016)

The first confocal scanning microscope was built by Marvin Minsky in 1955

Prof. Dr. Nikolai Lazarov

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1939, first commercial TEM(Ruska, von Borries)

Max Knoll and Ernst Ruska 1931, the first transmission electron microscope (TEM)

Electron microscope

Prof. Dr. Nikolai Lazarov

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1965, Charles Oatleythe first scanning EM (Stereoscan)

Electron microscope

Prof. Dr. Nikolai Lazarov

Electron microscopy

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1919

Atomic force microscope

Prof. Dr. Nikolai Lazarov

The first atomic force microscope was invented by IBM scientists in 1982

2020

Cryo-electron microscopy

Prof. Dr. Nikolai Lazarov

Prof. Dr. Nikolai Lazarov

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Freeze-Etching and Freeze-Fracture (Cryofacture)

Prof. Dr. Nikolai Lazarov

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Methods for observation of fixing cells and tissues

preparation of histological sections

– the paraffin technique steps:

removal of tissue: biopsy, necropsy

fixation: types of fixatives

rinsing

dehydration

clearing

infiltration

embedding: paraffin – Klebs (1869)

sectioning: microtome – Oschatz (1843)

staining: types of stains

mounting

specimen preparation for TEM

Johannes Purkinje

(1787-1869)

Prof. Dr. Nikolai Lazarov

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Methods for observation of fixing cells and tissues

Johannes Purkinje

(1787-1869)

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Interpretation of structures in tissue sections

Prof. Dr. Nikolai Lazarov

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Virtual microscopy

Prof. Dr. Nikolai Lazarov

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Virtual microscopy

Prof. Dr. Nikolai Lazarov

Prof. Dr. Nikolai Lazarov

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Thank you…