Analysis of gamete and zygote motility in Allomyces

Pommerville, Jeffrey C.

doi:10.1016/0014-4827(78)90096-4

Cited by 37 publications

(23 citation statements)

References 31 publications

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“…Although the analogs with threshold concentrations of 10 gM are a millionfold less potent than sirenin, there is no doubt that the male gametes are attracted by these analogs, and that structural variation understandably results in either a lack of male attraction or attraction only at higher threshold concentrations. Unfortunately, it is not possible to carry out competition or inhibition binding studies between sirenin and analogs because male gametes do not exhibit sensory adaptation while in a solution of active attractant (12,13). Rather they continue to undergo almost continuous directional changes and the addition of a second attractant goes "unnoticed" by the male cells.…”

Section: Discussionmentioning

confidence: 99%

“…macrogynus has the ability to attract male gametes (7,11). This dual sexual attraction system ensures that male and female gametes can locate one another efficiently and results in essentially 100% ofthe female gametes in a solution being fertilized by male cells (12).…”

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confidence: 99%

“…Furthermore, Machlis (8) was able to demonstrate that d-sirenin and isosirenin lacked activity, strongly suggesting the presence of receptors with specific structural requirements. Receptor studies involving competition binding or inhibition have not been possible to carry out due to the lack of sensory adaptation to sirenin by male gametes (12,13).…”

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confidence: 99%

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Effects of Analogs of the Fungal Sexual Pheromone Sirenin on Male Gamete Motility in Allomyces macrogynus

Pommerville¹,

Strickland²,

Romo³

et al. 1988

Plant Physiol.

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ABSTRACrThe ability of various structural analogs of the sexual pheromone sirenin to attract male gametes of the aquatic fungus Allomyces macrogynus was determined. Previous studies had shown that several structural analogs and stereoisomers of natural I-sirenin were devoid of activity at physiological concentrations. We now report the discovery of a structural analog that exhibits biological activity indistinguishable from the natural pheromone. The bioassay system used to determine chemotaxis was calibrated using synthetic, racemic sirenin, which exhibited a threshold concentration for gamete attraction at an applied concentration of 10 picomolar. The new synthetic monohydroxy analog of sirenin also had a threshold concentration of 10 picomolar. In the process of developing a new total synthesis of sirenin, a variety of other analogs were prepared and tested. All of these analogs exhibited threshold concentrations at 1 micromolar or higher, although attraction at these higher concentrations still varied according to their structural resemblance to sirenin. Thus, the results of these studies demonstrate that the hydroxymethyl group attached to the six-membered ring of sirenin is not essential for biological activity at physiological concentrations. The studies with other analogs demonstrate that biological activity at any concentration involves a balance between hydrophilic hydroxyl groups and hydrophobic hydrocarbon groups in the structure.The gametes of the aquatic fungus Allomyces macrogynus exhibit a dual attraction system. It was demonstrated recently (15) that the female gametes are attracted to the male gametes as a result of the production by the male gametes of a sexual pheromone called parisin. On the other hand, it has been known for some time that the sexual pheromone sirenin (4) produced by the female gametes ofA. macrogynus has the ability to attract male gametes (7,11 or chemically synthesized l-sirenin was active; none of the analogs exhibited any biological activity in chemotaxis bioassays (8). Furthermore, Machlis (8) was able to demonstrate that d-sirenin and isosirenin lacked activity, strongly suggesting the presence of receptors with specific structural requirements. Receptor studies involving competition binding or inhibition have not been possible to carry out due to the lack of sensory adaptation to sirenin by male gametes (12, 13).More recent studies into the mechanism of male chemotaxis in A. macrogynus (13) have been hindered by the unavailability of structural analogs that can be used to determine the basic structural features of sirenin necessary for biological activity. In addition, synthetic sirenin has not been available for comparing the potency of synthetic analogs as pheromones.Results described in this report demonstrate that synthetic sirenin analogs can exhibit biological activity identical to that of naturally occurring sirenin. These results provide information about chemical recognition by the male gametes of A. macrogynus. MATERIALS AND METHODSCultures. These studies w...

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Effects of Analogs of the Fungal Sexual Pheromone Sirenin on Male Gamete Motility in Allomyces macrogynus

Pommerville¹,

Strickland²,

Romo³

et al. 1988

Plant Physiol.

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“…Data on gamete size and speed were found for two species of isogamous green algae (Haxo & Clendenning, 1953;Racey et al, 1981;RuK !er & Nultsch, 1985), one anisogamous green alga (Togashi et al, 1997), one anisogamous aquatic fungus (Pommerville, 1978), sperm of a brown seaweed (Maier & MuK ller, 1986), and sperm of four sea urchin species (Chia et al, 1975;Gray, 1955;Levitan, 1993;Levitan et al, 1991). The rank correlation between gamete speed and volume was not signi"cant by either the Spearman or Kendall methods (StatView).…”

Section: Numerical Valuesmentioning

confidence: 99%

Selection for High Gamete Encounter Rates Explains the Success of Male and Female Mating Types

Dusenbery

2000

Journal of Theoretical Biology

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Sexual reproduction occurs in many small eukaryotes by fusion of similar gametes (isogamy). In the absence of distinguishable sperm and eggs, male and female mating types are missing. However, species with distinct males and females have so prospered that almost all familiar plants and animals have these mating types. Why has sexual reproduction involving sperm and eggs been so successful? An answer is obtained by considering physical limitations on encounter rates between gametes. A biophysical model based on well-established relationships produces "tness landscapes for the evolution of gamete size and energy allocation between motility and pheromone production. These landscapes demonstrate that selection for high gamete encounter rates favors large, pheromone-producing eggs and small, motile sperm. Thus, broadcast-spawning populations with males and females can reproduce at lower population densities and survive under conditions where populations lacking males and females go extinct. It appears that physical constraints on gamete encounter rates are su$cient to explain the "rst two steps in the isogamyPanisogamyPoogamyPinternal fertilization evolutionary sequence observed in several lineages of the eukaryotes. Unlike previous models, assumptions concerning zygote "tness or decreasing speed of swimming with increasing gamete size are not required.

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“…Species of the genus Allomyces are anisogamous with small motile male cells and larger less-motile female cells [126]. The male gametes swarm towards the female gametes, efficiently guided by pheromones produced by the latter [116], similar to gamete chemotactic signalling in broadcast spawners (see §3).…”

Section: Fungi Do It Toomentioning

confidence: 99%

Sexual selection in hermaphrodites, sperm and broadcast spawners, plants and fungi

Beekman

Nieuwenhuis

Ortiz‐Barrientos

et al. 2016

Phil. Trans. R. Soc. B

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One contribution of 15 to a theme issue 'Weird sex: the underappreciated diversity of sexual reproduction'. Darwin was the first to recognize that sexual selection is a strong evolutionary force. Exaggerated traits allow same-sex individuals to compete over access to mates and provide a mechanism by which mates are selected. It is relatively easy to appreciate how inter-and intrasexual selection work in organisms with the sensory capabilities to perceive physical or behavioural traits that signal mate quality or mate compatibility, and to assess the relative quality of competitors. It is therefore not surprising that most studies of sexual selection have focused on animals with separate sexes and obvious adaptations that function in the context of reproductive competition. Yet, many sexual organisms are both male and female at the same time, often lack sexual dimorphism and never come into direct contact at mating. How does sexual selection act in such species, and what can we learn from them? Here, we address these questions by exploring the potential for sexual selection in simultaneous hermaphrodites, sperm-and broadcast spawners, plants and fungi. Our review reveals a range of mechanisms of sexual selection, operating primarily after gametes have been released, which are common in many of these groups and also quite possibly in more familiar (internally fertilizing and sexually dimorphic) organisms.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'.

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Analysis of gamete and zygote motility in Allomyces

Cited by 37 publications

References 31 publications

Effects of Analogs of the Fungal Sexual Pheromone Sirenin on Male Gamete Motility in Allomyces macrogynus

Effects of Analogs of the Fungal Sexual Pheromone Sirenin on Male Gamete Motility in Allomyces macrogynus

Selection for High Gamete Encounter Rates Explains the Success of Male and Female Mating Types

Sexual selection in hermaphrodites, sperm and broadcast spawners, plants and fungi

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