No abstract

No abstract

Protoplasts from Chlamydomonas smithii prepared by the action of C. reinhardii gamete autolysine have been studied with respect to cell wall regeneration. "Natural" protoplasts within sporangia were also investigated for purposes of comparison. In both cases a new cell wall is completed within 2-3 h of the onset of regeneration. The first visible stages of wall regeneration are to be seen after 40-60 min as a fine fringe outside of the plasmalemma. The development of the typical "central triplet" follows within the next 1 h. Cell wall regeneration is reversibly inhibited by cycloheximide (10μg ml(-1)) and reversibly disturbed by concanavalin A (50 μg ml(-1)). Actinomycin D at concentration over 100μg ml(-1) also inhibit but the inhibition is irreversible and peculiar membrane effects are observed. Chelators (ethylenediamine tetraacetic acid; ethyleneglycol-bis-aminoethyl ether) and 2-deoxyglucose slightly retard or have no effect on cell wall regeneration.

No abstract

The process of coating textiles with a blade coater has been investigated with CFD (Computational Fluid Dynamics) software. The simulations have uncovered a pressure drop in the area between the edge of the knife and the textile. This drop can be explained by the varying height of the flow channel which is made of the knife and the textile in conjunction with the no slip condition that is applied to the walls. In the simulations this drop became arbitrarily deep with increasing viscosity leading to negative absolute pressure levels. This may be a hint that the no slip condition is not valid in this scenario that involves shear rates of the order of 103/s and dynamic viscosities of around 10 to 100Pas. With a proposed slip condition for the textile the pressure drop became less pronounced. At the same time the flow rate through the gap between knife and textile was reduced leading to a thinner coating. This can be a hint that a slip between coating material and textile can cause distortions in the coating up to a complete disruption which is reported frequently by the industry. This could eventually be avoided by reducing the varying height of the flow channel. Alternatively a vertical lift of the textile due to the negative pressure was taken into account. This lift appeared only with low tensions of the textile of about 1N/m and showed no influence on coating thickness and pressure drop.

Strains of Chlamydomonas with cross‐reacting sporangium wall autolysins also correspond in morphology, reproduction, development, and physiological properties. We therefore undertook a revision of the systematics of the genus based on this correlation. Isolates of Chlamydomonas available in culture collections were re‐examined microscopically, preferably with respect to their reproduction and development. In particular all authentic clones, on which earlier species diagnoses had been founded, were included. Their detectable autolysins were tested crosswise in bioassays. We intend to complete and extend species diagnoses in order to separate species more precisely. ‐ At first 7 strains with a common sporangium autolysin have been examined, four of which are the authentic cultures of the species C. aggregate Deason et Bold, C. akinetos Deason et Bold, C. applanata Pringsheim, and C. humicola Lucksch. They have been brought together under the name of the species first described, C. applanata Pringsheim, due to their apparent similarities in morphology and development. An amended species diagnosis is presented. The significance of authentic cultures as important sources of further information is discussed.

No abstract

No abstract