THE EFFECT OF TWO DIFFERENT PHOTOPERIODS ON THE OCCURRENCE OF MACRO-AND MICRO-THALLI IN THE LIFE CYCLE OF THE BROWN ALGA COLPOMENIA SINUOSA FROM THE FRENCH MEDITERRANEAN COAST

Field material of Herpodiscus durvillaeae, a New Zealand endemic parasitic brown alga growing in the thalli of Durvillaea antarctica, was studied in the laboratory. Pale zoids released from diminutive gametophytes, which were attached to the walls of unilocular sporangia and vegetative filaments of Herpodiscus, acted as isogametes. A heteromorphic life cycle with alternation of an endophytic parasitic sporophyte and a diminutive gametophyte is thus proposed for H. durvillaeae, and taxonomic implications of this life history are discussed. Key words: Herpodiscus durvillaeae, sexuality, life history, Phaeophyceae, Durvillaea antarctica, parasite.

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Meroditerpenes from the brown alga Cystoseira crinita off the french mediterranean coast

Phytochemistry ◽

10.1016/0031-9422(95)00303-o ◽

1995 ◽

Vol 40 (2) ◽

pp. 495-500 ◽

Cited By ~ 8

Author(s):

Annie Praud ◽

Robert Valls ◽

Louis Piovetti ◽

Bernard Banaigs ◽

Jean-Yves Benaïm

Keyword(s):

Brown Alga ◽

Mediterranean Coast

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Histone modifications during the life cycle of the brown alga Ectocarpus

Genome Biology ◽

10.1186/s13059-020-02216-8 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Simon Bourdareau ◽

Leila Tirichine ◽

Bérangère Lombard ◽

Damarys Loew ◽

Delphine Scornet ◽

...

Keyword(s):

Life Cycle ◽

Histone Modifications ◽

Brown Alga ◽

Land Plant ◽

Transcription Start ◽

Post Translational Modifications ◽

Transcription Start Sites ◽

Genomic Regions ◽

Active Genes

Abstract Background Brown algae evolved complex multicellularity independently of the animal and land plant lineages and are the third most developmentally complex phylogenetic group on the planet. An understanding of developmental processes in this group is expected to provide important insights into the evolutionary events necessary for the emergence of complex multicellularity. Here, we focus on mechanisms of epigenetic regulation involving post-translational modifications of histone proteins. Results A total of 47 histone post-translational modifications are identified, including a novel mark H2AZR38me1, but Ectocarpus lacks both H3K27me3 and the major polycomb complexes. ChIP-seq identifies modifications associated with transcription start sites and gene bodies of active genes and with transposons. H3K79me2 exhibits an unusual pattern, often marking large genomic regions spanning several genes. Transcription start sites of closely spaced, divergently transcribed gene pairs share a common nucleosome-depleted region and exhibit shared histone modification peaks. Overall, patterns of histone modifications are stable through the life cycle. Analysis of histone modifications at generation-biased genes identifies a correlation between the presence of specific chromatin marks and the level of gene expression. Conclusions The overview of histone post-translational modifications in the brown alga presented here will provide a foundation for future studies aimed at understanding the role of chromatin modifications in the regulation of brown algal genomes.

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Change in Setal Pattern during Early Development of Eupolymnia Nebulosa (Polychaeta: Terebellidae) Grown in Simulated Natural Conditions

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400028794 ◽

1988 ◽

Vol 68 (4) ◽

pp. 677-687 ◽

Cited By ~ 13

Author(s):

M. Bhaud

Keyword(s):

Growth Rate ◽

Life Cycle ◽

Adaptive Significance ◽

Mediterranean Coast ◽

Evolutionary Relationships ◽

Juvenile Growth ◽

Natural Conditions ◽

Morphological Organization ◽

Yield Information ◽

The Family

Eupolymnia nebulosa (Montagu) is a tubicolous worm with its body divided into two regions: thorax with biramous segments and three pairs of gills; abdomen with numerous segments lacking notopodia. The head bears grooved foodgathering tentacles which are not retractile into the mouth. The worm, a typical deposit feeder, lives in mucous tubes encrusted with sand. Although the family Terebellidae is homogeneous in terms of body organization and feeding ecology, there is a remarkable heterogeneity of developmental pattern. In the genera Lanice and Loimia, the life-cycle involves two pelagic stages separated by a short benthic larval stage; in other genera the development is mixed or direct (Bhaud et al. 1987; Pechenik, 1979; Caswell, 1981). It is important to study the development of representatives of the family which may reveal the adaptive significance of the different modes of development or may yield information about evolutionary relationships within the family. In several previous papers larval development (Bhaud & Grémare, 1988 a, b) and reproductive biology (Bhaud et al. 1987) of E. nebulosa have been reported from the Mediterranean coast. The present article reports observations on juvenile growth and morphological organization in natural conditions. This is the first step to growth rate studies in terms of temperature and food supply (Bhaud, 1988).

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