chemotaxis and its significance in biology and clinics
DESCRIPTION
Chemotaxis and its significance in biology and clinics. Dr. habil. Kőhidai László 2012. Other Cell-physiological effects (e.g. proliferation). Adhesion. Chemotaxis. Phagocytosis. Chemotaxis – Significance in biology. Helps to distinguish / to approach food molecules - PowerPoint PPT PresentationTRANSCRIPT
Chemotaxis and its significance in biology and
clinics
Dr. habil. Kőhidai László
2012.
ChemotaxisChemotaxis PhagocytosisPhagocytosisAdhesionAdhesion
Other Other Cell-physiological Cell-physiological effects effects (e.g. proliferation)(e.g. proliferation)
Chemotaxis – Significance in biologyChemotaxis – Significance in biology
Helps to distinguish / to approach food moleculesHelps to distinguish / to approach food molecules
Helps to avoid biologically harmful/toxic substances Helps to avoid biologically harmful/toxic substances
Sperm to approach oocyte - fertilization Sperm to approach oocyte - fertilization
Tissue transformation processes (e.g. CNS) Tissue transformation processes (e.g. CNS)
Immune reaction of multicellular organismsImmune reaction of multicellular organisms
Proliferation and growing of tumors, formation Proliferation and growing of tumors, formation
of metastasisof metastasis
Migration
Kinesis Taxis
Chmokinesis(direction)
Ortokinesis(speed)
Klinokinesis(frequency)
Chemotaxis Haptotaxis Necrotaxis
Chemoattractant materials
Chemorepellent materials
Basic concepts – Definitions 1Basic 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 theenvironment.
VECTORIAL movement
ChemotaxisChemotaxis
Chemokinesis:
Characteristic parameters (speed, frequency, amplitude) of motile cells are randomely changing due to the influence of environmental factors.
NON vectorial !
Basic concepts – Definitions 2Basic concepts – Definitions 2
ChemokinesisChemokinesis
Concentration of meolacules inducing migration
Chemotaxis – Induced by dissolved moleculesChemotaxis – Induced by dissolved molecules
Concentration gradient of moleculesbound onto the surface
Effect of molecules bound to the surfaceEffect of molecules bound to the surface
HaptotaxisHaptotaxis
NecrotaxisNecrotaxis
LASER
Migration of cells is modulated (induced or blocked) by the biologicallyactive substances released from the dead cells.
Nekrotaxis
Conditions of migrationConditions of migration
Ligands/substances inducing the migration
Motile cells
Receptors capable to detect ligandsReceptors capable to detect ligands
Effector mechanisms – e.g. cytoskeletal systemEffector mechanisms – e.g. cytoskeletal system
Main steps accompanying receptor Main steps accompanying receptor dependent migration of eukaryotesdependent migration of eukaryotes
Deformation of the cellDeformation of the cell
Cell adhesionCell adhesion
Cilliary/ flagellar movementCilliary/ flagellar movement
Chemotactic substancesChemotactic substances
Main groups of chemoattractant ligandsMain groups of chemoattractant ligands
ions of inorganic saltsions of inorganic salts (K+, Cl-)
amino acids (methionine, serine)
biogenic amines
oligopeptidesoligopeptides (bacterial tripeptidesbacterial tripeptides)
hormones (insulin)
chchemokines (interleukin 8interleukin 8)
feromones
synthetic substances (drugs)
Target cellsTarget cells
„„Classical” target cellsClassical” target cells
bacteria
ciliated eukaryotes
amebas
Target cells in higher ranked organismsTarget cells in higher ranked organisms
neutrophil granulocyte endothel
monocyte eosinophil granulocytelymphocyte
ReceptorsReceptors
Receptor classesReceptor classes
HormoneHormone
ImmuneImmune
Nerve systemNerve system
DrugDrug
LigandLocation
Surface membraneSurface membrane
CytoplasmeCytoplasme
NucleusNucleus
Main characteristics of receptorsMain characteristics of receptors
Specificity – structureSpecificity – structure
Affinity – effect at low conc.Affinity – effect at low conc.
Saturabiliy – number of receptorsSaturabiliy – number of receptors
ReversibilityReversibility
Specific response of the cellSpecific response of the cell