Limits...
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

Chamber design and assay set up for the chemotaxis experiment. Three coverslips (1 large rectangular and 2 small and square) were fixed on to each slide to create a chamber at the centre. For each assay, 7 µl microgamete culture was placed into the chamber, followed immediately by 2 μl of the treatment to create an interface. “A” represents the area counted for the away location, and “I” for the interface location. a View from above, b view from the side (not to scale)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig1: Chamber design and assay set up for the chemotaxis experiment. Three coverslips (1 large rectangular and 2 small and square) were fixed on to each slide to create a chamber at the centre. For each assay, 7 µl microgamete culture was placed into the chamber, followed immediately by 2 μl of the treatment to create an interface. “A” represents the area counted for the away location, and “I” for the interface location. a View from above, b view from the side (not to scale)

Mentions: This experiment tested whether P. berghei microgametes preferentially aggregate in regions containing material from females, when compared to regions containing material from RBC or asexual stages. Glass chambers were constructed using slides, coverslips fixed with optical adhesive (Norland) and UV light, as detailed in Fig. 1, to create an assay environment without ‘flow’. This means that all microgamete movement is due to Brownian motion plus their own motility. For each assay, microgametes were isolated from 20 μl infected blood, placed into 20 μl ookinete media (RPMI + 10 % fetal calf serum, pH 8, 20 °C) for 20 min (to allow sufficient time for the activation of male gametocytes, exflagellation and release of microgametes), and then spun down at 2000 rpm for 1 min to produce a supernatant containing purified microgametes. 7 μl of the supernatant was placed in the test chamber, immediately followed by 2 μl of the cue treatment material, as illustrated in Fig. 1. This arrangement creates two distinct, separate regions within the sample chamber: inside or at the interface with the cue treatment (“I”) and at least 12.5 mm away (“A”) from the interface. The probability that any particles (i.e., cue material and cells) placed at the interface had diffused into the ‘A’ location within 20 min—the total duration of the experiments—is less than 6 × 10−13 assuming typical molecular diffusivity, no edge effects, and that the distance along the chamber is the only relevant quantity (i.e., concentration is constant as a function of channel width and height) [44].Fig. 1


Ecological influences on the behaviour and fertility of malaria parasites.

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

Chamber design and assay set up for the chemotaxis experiment. Three coverslips (1 large rectangular and 2 small and square) were fixed on to each slide to create a chamber at the centre. For each assay, 7 µl microgamete culture was placed into the chamber, followed immediately by 2 μl of the treatment to create an interface. “A” represents the area counted for the away location, and “I” for the interface location. a View from above, b view from the side (not to scale)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig1: Chamber design and assay set up for the chemotaxis experiment. Three coverslips (1 large rectangular and 2 small and square) were fixed on to each slide to create a chamber at the centre. For each assay, 7 µl microgamete culture was placed into the chamber, followed immediately by 2 μl of the treatment to create an interface. “A” represents the area counted for the away location, and “I” for the interface location. a View from above, b view from the side (not to scale)
Mentions: This experiment tested whether P. berghei microgametes preferentially aggregate in regions containing material from females, when compared to regions containing material from RBC or asexual stages. Glass chambers were constructed using slides, coverslips fixed with optical adhesive (Norland) and UV light, as detailed in Fig. 1, to create an assay environment without ‘flow’. This means that all microgamete movement is due to Brownian motion plus their own motility. For each assay, microgametes were isolated from 20 μl infected blood, placed into 20 μl ookinete media (RPMI + 10 % fetal calf serum, pH 8, 20 °C) for 20 min (to allow sufficient time for the activation of male gametocytes, exflagellation and release of microgametes), and then spun down at 2000 rpm for 1 min to produce a supernatant containing purified microgametes. 7 μl of the supernatant was placed in the test chamber, immediately followed by 2 μl of the cue treatment material, as illustrated in Fig. 1. This arrangement creates two distinct, separate regions within the sample chamber: inside or at the interface with the cue treatment (“I”) and at least 12.5 mm away (“A”) from the interface. The probability that any particles (i.e., cue material and cells) placed at the interface had diffused into the ‘A’ location within 20 min—the total duration of the experiments—is less than 6 × 10−13 assuming typical molecular diffusivity, no edge effects, and that the distance along the chamber is the only relevant quantity (i.e., concentration is constant as a function of channel width and height) [44].Fig. 1

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