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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

Dose response to GAFs. Mean ± SEM of log2 transformed densities of exflagellating males (a) and ookinetes (b) relative to the pH 8 control, when exposed to 10−6 to 10−2 M xanthurenic acid (XA), kyneurenic acid (KA), or tryptophan (Tryp). n = 10–11 (independent infections) for each GAF and dose combination
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Fig2: Dose response to GAFs. Mean ± SEM of log2 transformed densities of exflagellating males (a) and ookinetes (b) relative to the pH 8 control, when exposed to 10−6 to 10−2 M xanthurenic acid (XA), kyneurenic acid (KA), or tryptophan (Tryp). n = 10–11 (independent infections) for each GAF and dose combination

Mentions: Plasmodium berghei exflagellation rates follow variable patterns accross the different GAF concentrations (Fig. 2a, GAF*concentration: χ2,82 = 17.74, P < 0.0001, Additional file 1: Table 1). In agreement with previous studies [5–7], XA is the most potent GAF. At its peak of 10−3 M XA induces >6-fold more exflagellation than KA and >11-fold more than Tryp, but has an inhibitory effect at the highest concentration. That Tryp induced exflagellation was unexpected, but it was the least potent GAF. Little variation in exflagellation occurs in response to KA and Tryp over the range of concentrations tested, though there is a slight trend for inhibition at the highest concentrations. In the range of 10−3 to 10−5 M, XA is just as potent as pH 8 but KA and Tryp induced less than 50 % of that by pH8. Overall, the results are consistent with observations that XA at ~10−3M induces more exflagellation than other GAFs, though KA induces less exflagellation than previous studies [5]. Discrepencies may be due to differences in culture set up; in particular, the slightly lower pH used here.Fig. 2


Ecological influences on the behaviour and fertility of malaria parasites.

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

Dose response to GAFs. Mean ± SEM of log2 transformed densities of exflagellating males (a) and ookinetes (b) relative to the pH 8 control, when exposed to 10−6 to 10−2 M xanthurenic acid (XA), kyneurenic acid (KA), or tryptophan (Tryp). n = 10–11 (independent infections) for each GAF and dose combination
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig2: Dose response to GAFs. Mean ± SEM of log2 transformed densities of exflagellating males (a) and ookinetes (b) relative to the pH 8 control, when exposed to 10−6 to 10−2 M xanthurenic acid (XA), kyneurenic acid (KA), or tryptophan (Tryp). n = 10–11 (independent infections) for each GAF and dose combination
Mentions: Plasmodium berghei exflagellation rates follow variable patterns accross the different GAF concentrations (Fig. 2a, GAF*concentration: χ2,82 = 17.74, P < 0.0001, Additional file 1: Table 1). In agreement with previous studies [5–7], XA is the most potent GAF. At its peak of 10−3 M XA induces >6-fold more exflagellation than KA and >11-fold more than Tryp, but has an inhibitory effect at the highest concentration. That Tryp induced exflagellation was unexpected, but it was the least potent GAF. Little variation in exflagellation occurs in response to KA and Tryp over the range of concentrations tested, though there is a slight trend for inhibition at the highest concentrations. In the range of 10−3 to 10−5 M, XA is just as potent as pH 8 but KA and Tryp induced less than 50 % of that by pH8. Overall, the results are consistent with observations that XA at ~10−3M induces more exflagellation than other GAFs, though KA induces less exflagellation than previous studies [5]. Discrepencies may be due to differences in culture set up; in particular, the slightly lower pH used here.Fig. 2

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