Dataset Information

Novel sex cells and evidence for sex pheromones in diatoms.

ABSTRACT:

Background

Diatoms belong to the stramenopiles, one of the largest groups of eukaryotes, which are primarily characterized by a presence of an anterior flagellum with tubular mastigonemes and usually a second, smooth flagellum. Based on cell wall morphology, diatoms have historically been divided into centrics and pennates, of which only the former have flagella and only on the sperm. Molecular phylogenies show the pennates to have evolved from among the centrics. However, the timing of flagellum loss--whether before the evolution of the pennate lineage or after--is unknown, because sexual reproduction has been so little studied in the 'araphid' basal pennate lineages, to which Pseudostaurosira belongs.

Methods/principal finding

Sexual reproduction of an araphid pennate, Pseudostaurosira trainorii, was studied with light microscopy (including time lapse observations and immunofluorescence staining observed under confocal scanning laser microscopy) and SEM. We show that the species produces motile male gametes. Motility is mostly associated with the extrusion and retrieval of microtubule-based 'threads', which are structures hitherto unknown in stramenopiles, their number varying from one to three per cell. We also report experimental evidence for sex pheromones that reciprocally stimulate sexualization of compatible clones and orientate motility of the male gametes after an initial 'random walk'.

Conclusions/significance

The threads superficially resemble flagella, in that both are produced by male gametes and contain microtubules. However, one striking difference is that threads cannot beat or undulate and have no motility of their own, and they do not bear mastigonemes. Threads are sticky and catch and draw objects, including eggs. The motility conferred by the threads is probably crucial for sexual reproduction of P. trainorii, because this diatom is non-motile in its vegetative stage but obligately outbreeding. Our pheromone experiments are the first studies in which gametogenesis has been induced in diatoms by cell-free exudates, opening new possibilities for molecular 'dissection' of sexualization.

SUBMITTER: Sato S

PROVIDER: S-EPMC3202595 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Novel sex cells and evidence for sex pheromones in diatoms.

Sato Shinya S Beakes Gordon G Idei Masahiko M Nagumo Tamotsu T Mann David G DG

PloS one 20111026 10

<h4>Background</h4>Diatoms belong to the stramenopiles, one of the largest groups of eukaryotes, which are primarily characterized by a presence of an anterior flagellum with tubular mastigonemes and usually a second, smooth flagellum. Based on cell wall morphology, diatoms have historically been divided into centrics and pennates, of which only the former have flagella and only on the sperm. Molecular phylogenies show the pennates to have evolved from among the centrics. However, the timing of ...[more]

PMID: 22046412

Similar Datasets

Project description:Sex pheromones rapidly affect endocrine physiology and behaviour, but little is known about their effects on gene expression in the neuroendocrine tissues that mediate olfactory processing. In this study we exposed male goldfish for 6 h to waterborne 17,20betaP (4.3 nM) and PGF2α (3 nM), the main pre-ovulatory and post-ovulatory pheromones, respectively. Both treatments elevated milt volume (P = 0.001). Microarray hybridizations were used to male telencephalon samples following PGF2α treatment and identified 71 unique transcripts that were differentially expressed (q < 5%; 67 up, 4 down). Functional annotation of these regulated genes indicates that PGF2α pheromone exposure affects diverse biological processes including nervous system functions, energy metabolism, cholesterol/lipoprotein transport, translational regulation, transcription and chromatin remodelling, protein processing, cytoskeletal organization, and signalling. By using real-time RT-PCR, we further validated three candidate genes, ependymin-II, calmodulin-A and aldolase C, which exhibited 3 - 5 fold increase in expression following PGF2α exposure. Expression levels of some other genes that are thought to be important for reproduction were also determined using real-time RT-PCR. Expression of sGnRH was increased by PGF2α, but not 17,20betaP, whereas cGnRH expression was increased by 17,20betaP but not PGF2α. In contrast, both pheromones increase the expression of glutamate (GluR2a, NR2A) and gamma-aminobutyric acid (GABAA gamma2) receptor subunit mRNAs. This gene expression data link milt release and rapid modulation of neuronal transcription as part of the response to female sex pheromones. A total of four microarray slides were hybridized to study the effects of PGF2α on gene expression in the telencephalon. Control samples (N = 4) were pooled to form our reference or technical replicates while treatment samples (N = 4), which formed our biological replicates, were ran separately. In addition, two dye swaps were performed for our biological samples for the treatments.

Dataset Information

Novel sex cells and evidence for sex pheromones in diatoms.

Background

Methods/principal finding

Conclusions/significance

Publications

Novel sex cells and evidence for sex pheromones in diatoms.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure