Cytochemical localization of acid phosphatase in Stigeoclonium tenue (Chaetophorales, Chlorophyceae).

Nonspecific acid phosphatases are a group of enzymes whose activity increases the availability of exogenous and endogenous orthophosphate either through extra- or intracellular hydrolysis of phosphate compounds. Our study demonstrates the activity of acid phosphatases in the filamentous freshwater alga Stigeoclonium tenue. These enzymes were detected following a cerium-based method in which cerium was used as an orthophosphate-capture reagent.

Fine structural study of the red seaweed Gymnogongrus torulosus (Phyllophoraceae, Rhodophyta).

The present study analyzed several characters of the red seaweed Gymnogongrus torulosus, such as cellular structure of the thallus, cuticle, pit plug and cell wall ultrastructure, and morphology of some organelles like plastids, Golgi bodies and mitochondria. Also, anomalous chloroplasts with thylakoid disorganization were found in medullary cells. The significance of this thylakoid disposition is still unclear.

FINE STRUCTURE OF BIFLAGELLATE ZOOSPORES OF ASTEROCOCCUS SUPERBUS (TETRASPORALES, CHLOROPHYCEAE), INCLUDING THE ABSOLUTE CONFIGURATION OF THE FLAGELLAR APPARATUS.

The ultrastructure of zoospores of Asterococcus superbus (Cienk.) Scherffel was studied to provide ultrastructural data relevant to the systematic position of the genus. Our results demonstrated that the motile cells of A.