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Ecological influences on the behaviour and fertility of malaria parasites.

Carter LM, Pollitt LC, Wilson LG, Reece SE - Malar. J. (2016)

Bottom Line: Male gametes need to locate and fertilize females in the challenging environment of the mosquito blood meal, but remarkably little is known about the ecology and behaviour of male gametes.Specifically, the data confirm that: (a) rates of male gametogenesis vary when induced by the family of compounds (tryptophan metabolites) thought to trigger gamete differentiation in nature; and (b) complex relationships between gametogenesis and mating success exist across parasite species.In addition, the data reveal that (c) microparticles of the same size as red blood cells negatively affect mating success; and (d) instead of swimming in random directions, male gametes may be attracted by female gametes.

View Article: PubMed Central - PubMed

Affiliation: Ashworth Laboratories, School of Biological Sciences, Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK.

ABSTRACT

Background: Sexual reproduction in the mosquito is essential for the transmission of malaria parasites and a major target for transmission-blocking interventions. Male gametes need to locate and fertilize females in the challenging environment of the mosquito blood meal, but remarkably little is known about the ecology and behaviour of male gametes.

Methods: Here, a series of experiments explores how some aspects of the chemical and physical environment experienced during mating impacts upon the production, motility, and fertility of male gametes.

Results and conclusions: Specifically, the data confirm that: (a) rates of male gametogenesis vary when induced by the family of compounds (tryptophan metabolites) thought to trigger gamete differentiation in nature; and (b) complex relationships between gametogenesis and mating success exist across parasite species. In addition, the data reveal that (c) microparticles of the same size as red blood cells negatively affect mating success; and (d) instead of swimming in random directions, male gametes may be attracted by female gametes. Understanding the mating ecology of malaria parasites, may offer novel approaches for blocking transmission and explain adaptation to different species of mosquito vectors.

No MeSH data available.


Related in: MedlinePlus

Microgametes move towards a female cue. The mean proportion of microgametes (±95 % confidence interval) at the interface with either a control treatments (RBC and/or asexual stage material) or female material treatments (live female gametes or lysed female gametes) at the start of the assay (0–6 min), or after 20–26 min in the chamber (End). Note that 95 % CI are given instead of SEM for clarity of the borderline difference. N = 3 independent infections
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Fig5: Microgametes move towards a female cue. The mean proportion of microgametes (±95 % confidence interval) at the interface with either a control treatments (RBC and/or asexual stage material) or female material treatments (live female gametes or lysed female gametes) at the start of the assay (0–6 min), or after 20–26 min in the chamber (End). Note that 95 % CI are given instead of SEM for clarity of the borderline difference. N = 3 independent infections

Mentions: To investigate whether microgametes swim in random directions or preferentially move towards females, whether microgametes were attracted or repelled by material (cues) generated from: live female gametes, lysed female gametes, live asexuals, lysed asexuals, and uninfected RBCs was tested. There was no significant difference in microgamete location when comparing all five cue treatments individually (χ4,72 = 7.82, P = 0.098, Table S4), or when comparing live female gametes to lysed females (χ2,92 = 0.19, P = 0.907), or live asexuals to lysed asexuals (χ2,72 = 2.33, P = 0.313). Therefore, the analysis was simplified by combining cues into three categories: “RBC”, “asexuals” and “females”. There was no significant difference in the location of microgametes exposed to “RBC” and “asexuals” (χ2,52 = 1.81, P = 0.404) and so the cue treatments were simplified further, into two categories: “control” (RBC, live asexuals and lysed asexuals) and “females” (live and lysed). There was a borderline significant trend for microgametes to accumulate at an interface with “females” and be repelled from an interface of “control” cues (Fig. 5; χ1,52 = 3.83, P = 0.051). Specifically, after 20 min, the proportion of microgametes at an interface with female material increased by 11 % (from 0.50 to 0.56), and reduced by 6 % at an interface with control material (from 0.49 to 0.46). Whilst this difference of 17 % is of borderline statistical significance, it suggests that female gametes attract males and that microgametes search the blood meal non-randomly to find mates.Fig. 5


Ecological influences on the behaviour and fertility of malaria parasites.

Carter LM, Pollitt LC, Wilson LG, Reece SE - Malar. J. (2016)

Microgametes move towards a female cue. The mean proportion of microgametes (±95 % confidence interval) at the interface with either a control treatments (RBC and/or asexual stage material) or female material treatments (live female gametes or lysed female gametes) at the start of the assay (0–6 min), or after 20–26 min in the chamber (End). Note that 95 % CI are given instead of SEM for clarity of the borderline difference. N = 3 independent infections
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4835847&req=5

Fig5: Microgametes move towards a female cue. The mean proportion of microgametes (±95 % confidence interval) at the interface with either a control treatments (RBC and/or asexual stage material) or female material treatments (live female gametes or lysed female gametes) at the start of the assay (0–6 min), or after 20–26 min in the chamber (End). Note that 95 % CI are given instead of SEM for clarity of the borderline difference. N = 3 independent infections
Mentions: To investigate whether microgametes swim in random directions or preferentially move towards females, whether microgametes were attracted or repelled by material (cues) generated from: live female gametes, lysed female gametes, live asexuals, lysed asexuals, and uninfected RBCs was tested. There was no significant difference in microgamete location when comparing all five cue treatments individually (χ4,72 = 7.82, P = 0.098, Table S4), or when comparing live female gametes to lysed females (χ2,92 = 0.19, P = 0.907), or live asexuals to lysed asexuals (χ2,72 = 2.33, P = 0.313). Therefore, the analysis was simplified by combining cues into three categories: “RBC”, “asexuals” and “females”. There was no significant difference in the location of microgametes exposed to “RBC” and “asexuals” (χ2,52 = 1.81, P = 0.404) and so the cue treatments were simplified further, into two categories: “control” (RBC, live asexuals and lysed asexuals) and “females” (live and lysed). There was a borderline significant trend for microgametes to accumulate at an interface with “females” and be repelled from an interface of “control” cues (Fig. 5; χ1,52 = 3.83, P = 0.051). Specifically, after 20 min, the proportion of microgametes at an interface with female material increased by 11 % (from 0.50 to 0.56), and reduced by 6 % at an interface with control material (from 0.49 to 0.46). Whilst this difference of 17 % is of borderline statistical significance, it suggests that female gametes attract males and that microgametes search the blood meal non-randomly to find mates.Fig. 5

Bottom Line: Male gametes need to locate and fertilize females in the challenging environment of the mosquito blood meal, but remarkably little is known about the ecology and behaviour of male gametes.Specifically, the data confirm that: (a) rates of male gametogenesis vary when induced by the family of compounds (tryptophan metabolites) thought to trigger gamete differentiation in nature; and (b) complex relationships between gametogenesis and mating success exist across parasite species.In addition, the data reveal that (c) microparticles of the same size as red blood cells negatively affect mating success; and (d) instead of swimming in random directions, male gametes may be attracted by female gametes.

View Article: PubMed Central - PubMed

Affiliation: Ashworth Laboratories, School of Biological Sciences, Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK.

ABSTRACT

Background: Sexual reproduction in the mosquito is essential for the transmission of malaria parasites and a major target for transmission-blocking interventions. Male gametes need to locate and fertilize females in the challenging environment of the mosquito blood meal, but remarkably little is known about the ecology and behaviour of male gametes.

Methods: Here, a series of experiments explores how some aspects of the chemical and physical environment experienced during mating impacts upon the production, motility, and fertility of male gametes.

Results and conclusions: Specifically, the data confirm that: (a) rates of male gametogenesis vary when induced by the family of compounds (tryptophan metabolites) thought to trigger gamete differentiation in nature; and (b) complex relationships between gametogenesis and mating success exist across parasite species. In addition, the data reveal that (c) microparticles of the same size as red blood cells negatively affect mating success; and (d) instead of swimming in random directions, male gametes may be attracted by female gametes. Understanding the mating ecology of malaria parasites, may offer novel approaches for blocking transmission and explain adaptation to different species of mosquito vectors.

No MeSH data available.


Related in: MedlinePlus