A possible malaria control approach involves the dissemination in mosquitoes of inherited symbiotic microbes to block Plasmodium transmission. However, in the Anopheles gambiae complex, the primary African vectors of malaria, there are limited reports of inherited symbionts that impair transmission. We show that a vertically transmitted microsporidian symbiont (Microsporidia MB) in the An. gambiae complex can impair Plasmodium transmission. Microsporidia MB is present at moderate prevalence in geographically dispersed populations of An. arabiensis in Kenya, localized to the mosquito midgut and ovaries, and is not associated with significant reductions in adult host fecundity or survival. Field-collected Microsporidia MB infected An. arabiensis tested negative for P. falciparum gametocytes and, on experimental infection with P. falciparum, sporozoites aren’t detected in Microsporidia MB infected mosquitoes. As a microbe that impairs Plasmodium transmission that is non-virulent and vertically transmitted, Microsporidia MB could be investigated as a strategy to limit malaria transmission.

Background: The demonstration that the recently discovered Anopheles symbiont Microsporidia MB blocks malaria transmission in Anophelesarabiensis and undergoes vertical and horizontal transmission suggests that it is a promising candidate for the development of a symbiont-based malaria transmission-blocking strategy. The infection prevalence and characteristics of Microsporidia MB in Anopheles gambiae sensu stricto (s.s.), another primary vector species of malaria in Kenya, were investigated. Methods: Field-collected females were confirmed to be Microsporidia MB-positive after oviposition. Egg counts of Microsporidia MB-infected and non-infected individuals were used to infer the effects of Microsporidia MB on fecundity. The time to pupation, adult sex ratio and survival were used to determine if Microsporidia MB infection has similar characteristics in the host mosquitoes An. gambiae and An. arabiensis. The intensity of Microsporidia MB infection in tissues of the midgut and gonads, and in carcasses, was determined by quantitative polymerase chain reaction. To investigate horizontal transmission, virgin males and females that were either Microsporidia MB-infected or non-infected were placed in standard cages for 48 h and allowed to mate; transmission was confirmed by quantitative polymerase chain reaction targeting Microsporidia MB genes. Results: Microsporidia MB was found to naturally occur at a low prevalence in An. gambiae s.s. collected in western Kenya. Microsporidia MB shortened the development time from larva to pupa, but other fitness parameters such as fecundity, sex ratio, and adult survival did not differ between Microsporidia MB-infected and non-infected hosts. Microsporidia MB intensities were high in the male gonadal tissues. Transmission experiments indicated that Microsporidia MB undergoes both maternal and horizontal transmission in An. gambiae s.s. Conclusions: The findings that Microsporidia MB naturally infects, undergoes maternal and horizontal transmission, and is avirulent in An. gambiae s.s. indicate that many of the characteristics of its infection in An. arabiensis hold true for the former. The results of the present study indicate that Microsporidia MB could be developed as a tool for the transmission-blocking of malaria across different Anopheles species. Graphical

Anopheles mosquitoes are colonized by diverse microorganisms that may impact on host biology and vectorial capacity. Eukaryotic symbionts such as fungi have been isolated from Anopheles, but whether they are stably associated with mosquitoes and transmitted transstadially across mosquito life stages or to subsequent generations remains largely unexplored. Here, we show that a Leptosphaerulina sp. fungus isolated from the midgut of An. gambiae can be stably associated with An. gambiae host and that it imposes low fitness cost when re-introduced through co-feeding. This fungus is transstadially transmitted across An. gambiae developmental stages and to their progeny. It is present in field-caught larvae and adult mosquitoes at moderate levels across geographical regions. We observed that Leptosphaerulina sp. induces a distinctive melanotic phenotype across the developmental stages of mosquito. As a eukaryotic symbiont that is stably associated with An. gambiae Leptosphaerulina sp. can be explored for paratransgenesis.

ObjectiveTo bioprospect optimal phenological phases as source of novel molecules from native golden yellow Pleurotus citrinopileatus across four phenologies in both aqueous and ethanol extracts, and identify novel molecules responsible for these activities.MethodsStandard qualitative assay, Folin–Ciocalteu assay; aluminium chloride spectrophotometric, 2, 2-diphenyl-1-picrylhydrazyl, 2, 2′-azinobis (3-ethylbenzothiazoline-6-suslfonic acid, ferricyanide reducing antioxidant power were used to determine total flavonoid, polyphenols, radical scavenging, and reducing power. Spectrophotometric methods were used for lycopene, β-carotene, and total carotenoids, while liquid chromatography quadrupole time of flight mass spectrometry was used for identification and comparative quantitation of polyphenols and flavonoids across the four phenological states. ChemSpider™ database was used for the identification of compounds based on their empirical formula, accurate mass and literature review of previously reported compounds in mushroom.ResultsPrimordial phases exhibited higher contents of secondary metabolites than mature basidiocarps. Polyphenols content differed across physiological phases with primordials exhibiting significant high contents (P<0.05) [(13.803 ± 0.797) mg gallic acid equivalent/g dry weight]. Distribution of total flavonoids was significantly different (P<0.05) across physiological states and ranged from (3.311 ± 0.730) to (14.824 ± 0.890) mg quercetin equivalent g dry weight. Ten polyphenol acids and seven flavonoids compounds identified varied across these phases with primordials exhibiting relatively high peak areas. Total antioxidant activities showed a positive correlation with total polyphenols (r=0.969; P<0.05) and total flavonoids (r=0.960; P<0.05) across these phenologies.ConclusionsThese findings provide evidence that primordials of golden yellow mushroom as opposed to their fruiting bodies are potent sources of bioactive health molecules

Background: The discovery of the Anopheles symbiont, Microsporidia MB in An. arabiensis and the subsequent demonstration that it blocks malaria transmission, undergoes vertical and horizontal transmission suggests that it is a promising candidate for developing a symbiont-based malaria transmission-blocking strategy. We investigated the prevalence and characteristics of Microsporidia MB in An. gambiae s.s., another primary malaria vector species in Kenya. Methods: Field collected females were confirmed Microsporidia MB positive after oviposition. The egg counting of Microsporidia MB infected and non-infected individuals used to infer the effects of Microsporidia MBon fecundity. The duration to pupation, the adult sex ratio and survival were quantified to determine if Microsporidia MBinfection has similar characteristics in An. gambiae and An. arabiensis hosts. The intensity of Microsporidia MB infections in tissues such as midgut, gonads and carcasses was determined by qPCR. To investigate horizontal transmission, virgin individuals of opposite sexes that were either Microsporidia MB infected or non-infected were placed in the standard cages for 48 hours and allowed to mate. After this period, transmission was confirmed by assessment of Microsporidia MB infection status by qPCR. Results: We observed that Microsporidia MB is naturally found at low prevalence in Anopheles gambiae s.s. collected in Western Kenya. Microsporidia MB shortened development time from larvae to pupae, but other fitness parameters such as fecundity, sex ratio, and adult survival did not differ between Microsporidia MB infected and non-infected host. Microsporidia MB intensities were high in the male gonadal tissue. Transmission experiments indicate that Microsporidia MB utilizes both maternal and horizontal transmission in An. gambiae s.s. Conclusions: The finding that Microsporidia MB naturally infects An. gambiae s.s., undergoes maternal and horizontal transmission and is avirulent signifies that many of the characteristics of Microsporidia MB infection observed in An. arabiensis hold true for Anopheles gambiae s.s. This is an early indication that Microsporidia MB could equally be developed as a tool for malaria transmission blocking across different Anopheles species.