IMMUNOCYTOCHEMICAL CHARACTERIZATION OF THE INTRAPYRENOID THYLAKOIDS OF CRYPTOMONADS

Document Type

Article

Publication Date

1-1-1992

Publication Title

Journal of Phycology

Volume

28

Issue

1

First Page

64

Keywords

Chroomonas sp., Cryptophyta, Hemiselmis brunnescens, immunocytochemistry, photosystem I, II, phycobiliproteins, pyrenoid, Rubisco, thylakoid

Last Page

68

Abstract

Thylakoid lamellae extend into the pyrenoids of only two genera of cryptomonad algae, Chroomonas and Hemiselmis, We used immunoelectron microscopy to assess the photosynthetic competency of cryptomonad intrapyrenoid thylakoids. Intrapyrenoid thylakoids possess phycobiliproteins and the chlorophyll a/c2 light‐harvesting complex, both of which are associated with photosystem (PS) II in a light‐harvesting capacity. In addition, thylakoids that extend into the pyrenoid of Hemiselmis brunnescens were immunolabelled by anti‐PSI. These results indicate that cryptomonad intrapyrenoid thylakoids likely function in a manner analogous to thylakoids of the chloroplast stroma. Moreover, our observation that the Calvin cycle enzyme ribulose 1,5‐bisphosphate carboxylase/oxygenase (Rubisco) is pyrenoid‐localized in these two cryptophytes indicates that the processes of photosynthetic O2‐evolution and ribulose 1,5‐bisphosphate (RuBP) carboxylation/oxygenation are not spatially separated in these algae. Copyright © 1992, Wiley Blackwell. All rights reserved

DOI

10.1111/j.0022-3646.1992.00064.x

ISSN

00223646

E-ISSN

15298817

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