1. Chemotaxis and its significance in biology and clinics
Dr. habil. Kőhidai László
2019/02/20

2. Adhesion Chemotaxis Phagocytosis Other Cell-physiological effects
(e.g. proliferation)
Adhesion
Chemotaxis
Phagocytosis

3. Chemotaxis – Significance in biology
Helps to distinguish / to approach food molecules
Helps to avoid biologically harmful/toxic substances
Sperm to approach oocyte - fertilization
Tissue transformation processes (e.g. CNS)
Immune reaction of multicellular organisms
Proliferation and growing of tumors, formation
of metastasis

5. Chemoattractant materials
Chemorepellent materials

6. Basic concepts – Definitions 1
Chemotaxis:
Migratory response of self-directed, motile cells.
Direction and speed of migration is influenced by
the concentration of molecules solved in the
environment.
VECTORIAL movement

7. Chemotaxis

8. Basic concepts – Definitions 2
Chemokinesis:
Characteristic parameters (speed, frequency,
amplitude) of motile cells are randomely changing
due to the influence of environmental factors.
NON vectorial !

9. Chemokinesis

10. Chemotaxis – Induced by dissolved molecules
Concentration of meolacules inducing migration

11. Effect of molecules bound to the surface
Haptotaxis
Concentration gradient of molecules
bound onto the surface

12. Necrotaxis
LASER
Migration of cells is modulated (induced or blocked) by the biologically
active substances released from the dead cells.

13. Nekrotaxis

14. Conditions of migration
Ligands/substances inducing the migration
Motile cells
Receptors capable to detect ligands
Effector mechanisms – e.g. cytoskeletal system

15. Main steps accompanying receptor dependent migration of eukaryotes
Deformation of the cell
Cell adhesion
Cilliary/ flagellar movement

16. Chemotactic substances

17. Main groups of chemoattractant ligands
ions of inorganic salts (K+, Cl-)
amino acids (methionine, serine)
biogenic amines
oligopeptides (bacterial tripeptides)
hormones (insulin)
chemokines (interleukin 8)
feromones
synthetic substances (drugs)

18. Target cells

19. „Classical” target cells
bacteria
„Classical” target cells
amebas
ciliated eukaryotes

20. Target cells in higher ranked organisms
neutrophil granulocyte
endothel
monocyte
lymphocyte
eosinophil granulocyte

21. Receptors

22. Receptor classes Location Ligand Surface membrane Hormone Cytoplasme
Nucleus
Hormone
Immune
Nerve system
Drug
Ligand

23. Main characteristics of receptors
Specificity – structure
Affinity – effect at low conc.
Saturabiliy – number of receptors
Reversibility
Specific response of the cell