Amino Acid Incorporation in Developing Fucus Embryos

Abstract

Abstract. The incorporation of 14C-leucine and 14C-amino acid mixture into protein in unfertilized eggs and developing embryos of the brown alga Fucus vesiculosus L. was studied. Bacterial contamination was initially a problem, but it was found that the addition of 40 jug/ml chloramphenicol to the incubation medium would inhibit bacterial protein synthesis without affecting early development of the Fucus embryos. The kinetics of uptake and incorporation of 14C-leucine into the trichloroacetic acid-soluble and -insoluble fractions indicated that the exogenous precursor did not equilibrate with the main soluble leucine pool before incorporation into protein. Uptake and incorporation of leucine by embryos 90 to 175 minutes old were proportional to exogenous leucine concentration over the range 5 X 10-6 M to 5 X 10-3 M.Unfertilized eggs will incorporate 14C-leucine into protein. Gamete release was obtained as described by McCully (11). Male receptacles were placed in petri dishes at 150 in the light, and antheridia were usually extruded from the conceptacles within 12 to 24 hours. The female receptacles were placed in sea water in petri dishes at 150 in the light, and oogonia were usually released wvithin 4 to 6 hours.The eggs were released from the oogonia shortly thereafter.Just prior to fertilization, antheridia were rinsed from the male receptacles with sea water, releasing the sperm. A small volume of sperm suspension was added to a suspension of eggs, and the mixture was swirled. The gametes were kept at 150 in the light for at least 0.5 hour to allow ample time for fertilization to occur. Then the zygotes and sperm were rinsed through a Nitex nylon filter (Tobler, Ernst and

Observation of bacteria over the surface of released oogonia from Fucus vesiculosus L. (Phaeophyceae)

“…Although bacterial 'contamination' has been mentioned previously in an experiment with eggs and embryos of Fucus vesiculosus (Peterson & Torrey 1968), this is the first direct observation of bacteria over the surface of oogonia at the moment of their release from conceptacle (Fig. 2).…”

Development of Cell Polarity

“…This data and the elegant demonstration by Jaffe (33) that polarized light produces bipolar embryos, argues strongly for a polar axis which is initially labile and "arises in some more epigenetic manner than through the directed rotation of some preformed asymmetric structure." Postfertilization RNA and protein synthesis (72,77), as well as the acquisition of a sufficient pressure potential for rhizoid elongation (3,80), are also required for polar embryo formation.…”

The effect of irradiance and temperature on the germination of four species of Fucales

“…A method based on that of Peterson & Torrey (1968) was used for effecting gamete liberation in the dioecious species F. vesiculosus and F. serratus. The female receptacles were placed in sterile sea water in covered crystallizing dishes overnight at 10°C, 7.5 W m -a irradiance, and 16:g photoperiod for oosphere release to occur.…”