Is life conceivable without chemotaxis ?

Is life conceivable without chemotaxis ? Dr. habil. Kőhidai László 2011.

+ + Trichinella spiralis (1) 200 - 400 20 - 80

< + + Trichinella (2)

+ + + Trichinella (3)

Insects (1) • Responses to pheromones: in sec.-s • - direction of flying • - speed • - pattern (zick-zack) • Modulation of odorant receptors is durable • 1-2 min. - 20-95 min. ipsenol, ipsdienol, cis-verbenol • Dose ranges of responses are wide

+ Insects (2) • Heat-dependent responses 20 oC 26 oC steepness of flying • Different types of migrations/flying: • schemakinezis zikk-zakk • tropotaxis look-leap • klinotaxis

Insects (3) • Cockroach • pheromones inducing aggregation • ammónia, methylamine, di-, trimethylamine • 1-dimethylamino-2-methyl-2-propanol effective in10 pM • (50-1000x more active then other substances) • Differences in responses to diffuse and surface associated • pheromones

Effect of gamones Coagulation Hyaluronidase Gynogamone II. Androgamone II. Gynogamone I. Androgamone I.

Parts of female sexual organs releasing chemoattractants • Cervical mucus • Cavity of uterus • Follicular fluide • Cumulus cells • Intact, still not fertilized oocyte

Components of follicular fluide • Composition is sexual cycle dependant • LH • Progesterone (1-100 mg/ml) • Adrenalin (0.001 mg/mll • Oxytocin (0.01 U/ml) • Insulin (repellens) • Kallikrein • Anti-thrombin III. • = spermium receptor • Atrial natriuretic peptide (ANP=ANF) • 1000 Da, heat-stable protein

Other factors synthesized by the female organs and influencing the chemotaxis • pH • some proteases • resact – Ca2+ [mM] • speract – guanylate cyclase • chemoattractant substance perelased from the vegetative pole of oocyte Brown algae Ectocarpene 0.89 – 8.9 nmol/l the p-electone-distribution is essential

Population of spermiums is rather heterogeneous The respiratory response induced by follicular fluide: 70 % positive !!! 20 % negative Spermiums and chemotaxis (1) • Responsiveness is changing by the age of cells: • early matured aged • only these cells express normal responsiveness

Spermiums and chemotaxis (2) Ca2+ has a role in: chemotaxis cell respiratory proc. acrosome reaction cortocal reaction fertiléization cell adhesion Calmodulin – NAD-kinase – exocytosis phosphatases, phosphorylation guanylate cyclase cGMP cGMP-depend. Ca2+ channel Ca2+ influx when spermium reaches the oocyte

Spermiums and chemotaxis (3) • Methylation system • tail – protein carboxyl-methylase • head – tail – MAP • decreased phospholipid methylation (min. 40%) • cAMP-dependent phosphorylation • Protein kinase inhibitors are blockers of the system (42 kD kináz)

Spermiums and chemotaxis (4) • Common receptor-gene family in • odorant receptors and in spermium • fMLF and BOC-fMLP (10-9 – 10-8 M) • works as chemoattractant not only in leukocytes • BUT in spermiums, too. • (leukocyte accumulation is induced in the female • genital tract) • p-nitrophenyl-glycerol (PNPG) 10-5 M is repellent • in spermiums – contraceptive applications

Characterization of pheromones • Work on the individuals of the same species • Influence the sexual behaviour • Effects are expressed via pheromone-receptors • signaling is G-protein-linked • Influence development of hierarchy in the population • qualitative • differences • quantitative • Excreted in: feaces, urine, sweet and other body-fluids • Determined by MHC-genes • the same H2 (male-female) prefer each other

Pheromones (2) Mice Estrus-inhibition Anestrus Estrus (sensible period lasts 5 days, but mating desensibilizes it)

Pheromones (3) Non-self male excretes pheromones in the urine Level of heterozygocy is increased

Pheromones in lower levels of phylogeny (1) Saccharomyces cerevisiae • 7 transmembrane receptor • G-protein-linked • Clathrin haevy-chain dependent internalization Tetrahymena pyriformis • Attractant: tricosene ; imprinting + • Repellent: bornyl acetate ; imprinting 0

Pheromones in lower levels of phylogeny (2) • In Saccharomyces cerevisiae pheromones guide: • - development of mating projections • - intracellular migration of nucleus • Presence of N- and O-oligosaccharides • a-agglutinin (cell adhesion) – in the core region • 80-95% O-oligosach. • pheromones a-agglutinin-gene • cell-cell contacts

Pheromones in lower levels of phylogeny (3) • Fungi – Allomyces macrogynus Sirenin (1 pM – 1 mM) acts on gamets • H+, K+, NH4+, Na+, Ca2+, Mg2+, La3+ - ions are repellent itself - they can neutralize effects of each-other in competition

Practical applications of pheromones • Artificial feritlization /insemination • Anti-helmintic • Insect repellent

„T-shirt” test Self – Non-self ? Male – Female ?

Pheromones in human (1) • Determination capacity of own-odor 75% • Distinguish male/female (female scores are better) • Newborns – recognition of lactating breast • 2 days0 • 2 weeks+ but no differentiation • 6 weeks+ mother preference • Mating

Pheromones Dog age (days) self non-self 20-24> 31-36, 66-72 ~ 52-56 male

Pheromone in hide The chair labelled with male pheromone was preferred by female induviduals

Is life conceivable without chemotaxis ?