Dynamic Gut Microbiome across Life History of the Malaria Mosquito Anopheles gambiae in Kenya

The mosquito gut represents an ecosystem that accommodates a complex, intimately associated microbiome. It is increasingly clear that the gut microbiome influences a wide variety of host traits, such as fitness and immunity. Understanding the microbial community structure and its dynamics across mosquito life is a prerequisite for comprehending the symbiotic relationship between the mosquito and its gut microbial residents. Here we characterized gut bacterial communities across larvae, pupae and adults of Anopheles gambiae reared in semi-natural habitats in Kenya by pyrosequencing bacterial 16S rRNA fragments. Immatures and adults showed distinctive gut community structures. Photosynthetic Cyanobacteria were predominant in the larval and pupal guts while Proteobacteria and Bacteroidetes dominated the adult guts, with core taxa of Enterobacteriaceae and Flavobacteriaceae. At the adult stage, diet regime (sugar meal and blood meal) significantly affects the microbial structure. Intriguingly, blood meals drastically reduced the community diversity and favored enteric bacteria. Comparative genomic analysis revealed that the enriched enteric bacteria possess large genetic redox capacity of coping with oxidative and nitrosative stresses that are associated with the catabolism of blood meal, suggesting a beneficial role in maintaining gut redox homeostasis. Interestingly, gut community structure was similar in the adult stage between the field and laboratory mosquitoes, indicating that mosquito gut is a selective eco-environment for its microbiome. This comprehensive gut metatgenomic profile suggests a concerted symbiotic genetic association between gut inhabitants and host

The waaL gene mutation compromised the inhabitation of Enterobacter sp. Ag1 in the mosquito gut environment

Abstract Background The mosquito gut harbors a variety of bacteria that are dynamically associated with mosquitoes in various contexts. However, little is known about bacterial factors that affect bacterial inhabitation in the gut microbial community. Enterobacter sp. Ag1 is a predominant Gram negative bacterium in the mosquito midgut. Methods In a mutant library that was generated using transposon Tn5-mediated mutagenesis, a mutant was identified, in which the gene waaL was disrupted by the Tn5 insertion. The waaL encodes O antigen ligase, which is required for the attachment of O antigen to the outer core oligosaccharide of the lipopolysaccharide (LPS). Results The waaL − mutation caused the O antigen repeat missing in the LPS. The normal LPS structure was restored when the mutant was complemented with a plasmid containing waaL gene. The waaL − mutation did not affect bacterial proliferation in LB culture, the mutant cells grew at a rate the same as the wildtype (wt) cells. However, when waaL − strain were co-cultured with the wt strain or complemented strain, the mutant cells proliferated with a slower rate, indicating that the mutants were less competitive than wt cells in a community setting. Similarly, in a co-feeding assay, when fluorescently tagged wt strain and waaL − strain were orally co-introduced into the gut of Anopheles stephensi mosquitoes, the mutant cells were less prevalent in both sugar-fed and blood-fed guts. The data suggest that the mutation compromised the bacterial inhabitation in the gut community. Besides, the mutant was more sensitive to oxidative stress, demonstrated by lower survival rate upon exposure to 20 mM H2O2. Conclusion Lack of the O antigen structure in LPS of Enterobacter compromised the effective growth in co-culture and co-feeding assays. In addition, O-antigen was involved in protection against oxidative stress. The findings suggest that intact LPS is crucial for the bacteria to steadily stay in the gut microbial community

Dynamic Gut Microbiome across Life History of the Malaria Mosquito Anopheles gambiae in Kenya

The mosquito gut represents an ecosystem that accommodates a complex, intimately associated microbiome. It is increasingly clear that the gut microbiome influences a wide variety of host traits, such as fitness and immunity. Understanding the microbial community structure and its dynamics across mosquito life is a prerequisite for comprehending the symbiotic relationship between the mosquito and its gut microbial residents. Here we characterized gut bacterial communities across larvae, pupae and adults of Anopheles gambiae reared in semi-natural habitats in Kenya by pyrosequencing bacterial 16S rRNA fragments. Immatures and adults showed distinctive gut community structures. Photosynthetic Cyanobacteria were predominant in the larval and pupal guts while Proteobacteria and Bacteroidetes dominated the adult guts, with core taxa of Enterobacteriaceae and Flavobacteriaceae. At the adult stage, diet regime (sugar meal and blood meal) significantly affects the microbial structure. Intriguingly, blood meals drastically reduced the community diversity and favored enteric bacteria. Comparative genomic analysis revealed that the enriched enteric bacteria possess large genetic redox capacity of coping with oxidative and nitrosative stresses that are associated with the catabolism of blood meal, suggesting a beneficial role in maintaining gut redox homeostasis. Interestingly, gut community structure was similar in the adult stage between the field and laboratory mosquitoes, indicating that mosquito gut is a selective eco-environment for its microbiome. This comprehensive gut metatgenomic profile suggests a concerted symbiotic genetic association between gut inhabitants and host

Dataset Item 1, 2, and 3

This study examined the midgut metabolic profiles of Anopheles gambiae mosquitoes following feeding with sugar, human blood, mouse blood, and Plasmodium falciparum-infected human blood. GC/MS and LC/MS were used to determine the abundance of 512 metabolites. The dataset associated with this study includes 3 items, which are described as follows. Dataset Item 1 (Table) contains information about biochemicals, pathway assignment, and abundance, using the original scale. Dataset Item 2 (Table) contains information about biochemicals, pathway assignment, and abundance, using rescaled values. Dataset Item 3 (Images) contains graphical views of biochemical abundance. Each box plot presents the abundance of one compound in all samples

Data from: Anopheles gambiae: metabolomic profiles in sugar-fed, blood-fed and Plasmodium falciparum-infected midgut

The mosquito midgut is a physiological organ essential for the nutrient acquisition as well as an interface that encounters various mosquito borne pathogens. Metabolomic characterization would reveal biochemical fingerprints that are generated by various cellular processes. The metabolite profiles of the mosquito midgut will provide an overview of the biochemical events in both physiological states and the dynamic responses to pathogen infections. In this study, the midgut metabolic profiles of Anopheles gambiae mosquitoes following feeding with sugar, human blood, mouse blood, and Plasmodium falciparum-infected human blood were examined. A mass spectrometry system coupled to liquid and gas chromatography produced a time series of metabolites in the midgut at discrete conditions (sugar feeding, 24hr and 48hr post normal blood and P. falciparum-infected blood feeding). Triplicates were included to ensure system validity. A total of 512 individual compounds were identified, 511 were assigned to 8 super-pathways and 75 sub-pathways. The dataset can be used for further inquiry into the metabolic dynamics of sugar and blood digestion and of malaria parasite infection

Draft Genome Sequences of Elizabethkingia anophelis Strains R26T and Ag1 from the Midgut of the Malaria Mosquito Anopheles gambiae

Elizabethkingia anophelis is a species in the family Flavobacteriaceae. It is a dominant resident in the mosquito gut and also a human pathogen. We present the draft genome sequences of two strains of E. anophelis, R26T and Ag1, which were isolated from the midgut of the malaria mosquito Anopheles gambiae

Isoprenoid synthesis pathway in four bacterial species.

<p>The color code represents the enzymes that are present in the species.</p

Graphic view of a syntenic gene cluster that is conserved in five taxa of Bacteroidetes.

<p>The genes encoding the components of TonB dependent transporters are ExbB, ExbD and TonB. Locus ID of each gene is given in the boxes, with taxon prefix (e.g. D505_ for <i>E.a.</i>) in the ExbB box for each species. The box with * in <i>D. fermentans</i> represents a predicted gene encoding a hypothetic protein. The scale bar represents 1 kb in length. Phylogenetically, <i>E. anophelis</i> and <i>F. johnsoniae</i> belong to the class Flavobacteria, <i>Dyadobacter fermentans</i> belongs to the class Cytophagia, <i>Arcticibacter svalbardensis</i> is in the class Sphingobacteriia, and <i>Bacteroides thetaiotaomicron</i> is located in the class Bacteroidia.</p