Regulation der Cilienmetachronie bei der “Fluchtreaktion” von Paramecium*

SYNOPSIS. Paramecia induced to perform high rates of avoiding reactions by mechanical stimulation and the action of Ba ions were instantaneously fixed with OsO₄. Quantitative evaluation of the preparations revealed, among other things, metachronal stages of the transition between the ciliary patterns of swimming backward and forward. In each of the transitory stages, metachronal waves of swimming forward were found at the anterior end and waves of swimming backward at the posterior end of the animal. This confirms the so-called Párducz-scheme of avoiding reaction for the case of homogeneous chemical stimulation as well as for mechanical stimulation.     

Nachtrag zur “Wurmtheorie” der Vertebraten-Evolution1

This paper presents some new arguments for the metameric-wonn-theory for the evolution of the Vertebrates (Gutmann 1966a). Metameric coelomoducts in Enteropneust larvae (Goodrich 1947) which should be interpreted as metanephridia show that the Enteropneusts can be derived from metameric Chordate-like predecessors. The myomeres of Branchiostoma are no solid organs as there exist sclerocoels. These must be interpreted as vestigial coelomic cavities. They can be cited as a proof for the metameric worm-theory. They function as a canal system, which gathers excretory stuff in the myomeres which these organs could otherwise not get rid of. The coelom-cavities are cleaned by the protonephridia in the gill region. Some additional details of the phylogenetic transformation of metameric coelom cavities into myomeres are reconstructed. It is shown that the problem of coelomic and myomeric metamerism cannot be solved in the way proposed in the literature concerned with this question. The metameric-worm-theory for the evolution of the Vertebrates pretends that metameric metanephridia were fused on the lower level of Vertebrate phylogeny and formed the archinephric ducts. A paper of Goodrich (1947) shows that there are similar cases of fused metanephridia in some Annelids. These are parallels to the postulated formation of the metanephridia in the lowest Vertebrates. The archinephric duct acquired its muscular coat when it was formed by fusion of metanephridia in the bodywall. Muscles of the body wall took over a new function by making peristaltic movements of the newly formed archinephric ducts possible. When the archinephric duct was moved back into the coelom it did not lose the still functioning muscular coat.     

Der „Sekundenkleber“ der Stummelfüßer

Novel insights into the “superglue” of velvet worms The biological “superglue” of velvet worms provides inspiration towards circular processing of advanced polymers. In nature, velvet worms employ a fluid, protein‐rich secretion for hunting and defense, which forms rapidly into stiff fibers. The fluid‐to‐fiber transition occurs outside the body without regulations, indicating that the “instructions” for assembly are programmed into the protein building blocks. Electrostatic interactions between oppositely charged protein domains and free ions drive protein folding, self‐organization (coacervation) and stabilization of the building blocks into nanoscale droplets. Yet, nanodroplets can be instantly transformed via simple mechanical stimulus as proteins partially unfold, merge together and form a strong network, which solidifies into a fiber. The mechanism is based on basic physico‐chemical principles. Thus, by extracting these principles, new methods of synthesizing sustainable polymer‐based materials can be developed.