Versuche zur Gliederung des Entwicklungsverlaufs derChlorella-Zelle

Abstract

EinleitungIn vor~usgehenden Arbeiten (Lo~z] ~N 1956, 1957; Plxso~ und LoR]~z~ 1958) war eine Methode znr Erzielung ]complett synehroner Chlorella-Kulturen dutch Licht-Dunkel-Weehsel besehrieben und die Beeinflussung des Wachstumsverlaufs synehronisierter Zellen durch Temperatur und Lichtgenui] verfolgt worden. Es wurde nunmehr auf eine genauere Bearbeitung physiologischer Vorgange wahrend der Zellentwicklung (des ,,life cycle") iibergegangen. Die Entwieklung einer Chlorellazelle unseres Stammes ls sich zunachst formal in zwei Absehnitte gliedern (vgl. Abb.

Synchronous Cultures of Algae

“…Whereas the formation of RNA proceeds almost in parallel with that of protein, the formation of DNA takes place only slowly during the growing phase and occurs abruptly at a considerable rate at the stages of ripening (L2---> L4). Such a sudden increase of DNA occurring at a cer tain stage of ripening was later reported for C. pyrenoidosa (34,82,94,100,138,141,143,144,158,193,195,214); the high temperature Chlorella (57); and E. gracilis, strain Z (32) [but not for another strain of E. gracilis (19) and ChI. moewusii (12)].…”

“…As a counterpart of the division-inducing factor assumed by the Japanese workers, a pace-maker (Zeitgeber) of cellular division was postulated by the German authors for C. pyrenoidosa (93,96,100,138,143,145,165,166,174). The Zeitgeber is stated to be the time of beginning of the light period in their programmed light-dark regime.…”

“…Carbohydrates and lipids.-Ruppel (158) reported that, in C. pyrenoidosa, the content (per unit dry weight of cells) of total carbohydrate increased during the light phase and decreased-with concomitant increase of pro tein-during the dark period [see also (100,138,145)]. With C. ellipsoidea Hase, Morimura & Tamiya (5 1) and Otsuka (130) observed that, during the whole course of the algal life cycle, starch formed the major part of the carbo hydrates, and sucrose was the main sugar extractable with hot 80 per cent ethanol.…”

Untitled

“…Representative data of synchronous cultures of various algae obtained by this method are given in Table I. In most of the cases listed in the Table, the synchrony was "complete"-a terminology proposed by German workers (100,144)-which means that the division of all, or practically all, cells takes place during a certain period (usually the dark period) of one light-dark cycle. In the third column are given the divi sion numbers, n and n ' , the former being the real number of daughter cells liberated from individual mother cells and the latter the average value ob tained for the whole population.…”

“…As a counterpart of the division-inducing factor assumed by the Japanese workers, a pace-maker (Zeitgeber) of cellular division was postulated by the German authors for C. pyrenoidosa (93,96,100,138,143,145,165,166,174). The Zeitgeber is stated to be the time of beginning of the light period in their programmed light-dark regime.…”