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Impact of gut microbiota on the fly's germ line.

Elgart M, Stern S, Salton O, Gnainsky Y, Heifetz Y, Soen Y - Nat Commun (2016)

Bottom Line: Unlike vertically transmitted endosymbionts, which have broad effects on their host's germ line, the extracellular gut microbiota is transmitted horizontally and is not known to influence the germ line.We further show that the main impact on oogenesis is linked to the lack of gut Acetobacter species, and we identify the Drosophila Aldehyde dehydrogenase (Aldh) gene as an apparent mediator of repressed oogenesis in Acetobacter-depleted flies.The finding of interactions between the gut microbiota and the germ line has implications for reproduction, developmental robustness and adaptation.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.

ABSTRACT
Unlike vertically transmitted endosymbionts, which have broad effects on their host's germ line, the extracellular gut microbiota is transmitted horizontally and is not known to influence the germ line. Here we provide evidence supporting the influence of these gut bacteria on the germ line of Drosophila melanogaster. Removal of the gut bacteria represses oogenesis, expedites maternal-to-zygotic-transition in the offspring and unmasks hidden phenotypic variation in mutants. We further show that the main impact on oogenesis is linked to the lack of gut Acetobacter species, and we identify the Drosophila Aldehyde dehydrogenase (Aldh) gene as an apparent mediator of repressed oogenesis in Acetobacter-depleted flies. The finding of interactions between the gut microbiota and the germ line has implications for reproduction, developmental robustness and adaptation.

No MeSH data available.


Related in: MedlinePlus

Lack of gut microbiota represses oogenesis and alters early embryonic development in the next generation.(a) Representative images of DAPI-stained ovaries at day 6 after eclosion, shown for untreated case (control) and for females developed from dechorionated eggs that were placed on food without bacteria (Dechor.) and food supplemented with single species of native Acetobacter (Dechor.+Aceto) or Lactobacillus (Dechor.+Lacto). Note the reduction in the size of the ovary and the number of mature oocytes without extracellular gut bacteria. (b) Number of oocytes per ovary and percentages of oocytes at stages 8–10 and 11–14 for the cases in a. Mean±s.e. based on three replicated experiments each with >20 ovaries. (c) Egg deposition over 4 h period relative to control. Mean fold-change ±s.e. based on three replicated experiments, each containing >20 females. (d) Total number of eggs deposited per female over a period of 5 days. Mean±s.e. based on three replicates, each with n>7. (e) Scatter plot of transcript levels (RPKM) in embryos of bacterial-depleted flies (Dechor.) versus control embryos (both at 2 h after egg deposition, ‘AED'). Each point represents average transcript levels based on 6 RNA-seq analyses per condition (three wild-type strains, each measured in duplicates). Blue and green overlays display maternal and zygotic transcripts selected based on Thomsen et al.29 and De-Renzis et al.31, respectively. (f) Global reduction in the levels of maternal transcripts and reciprocal increase in zygotic transcripts in 2 h AED embryos of bacterial-depleted flies versus control embryos. Maternal and zygotic transcripts were defined based on Lott et al.30. (g) Correlation between the half-life of maternal transcripts (based on ref. 29) and their extent of reduction in bacterial-depleted (Decor.) versus control embryos. (h) Representative enrichments of Gene Ontology (GO) annotations in groups of transcripts that were differentially expressed in 2 h AED embryos of bacterial-depleted flies compared to control embryos (pink and light blue) or to a stage-matched transcriptome (red and blue). Enrichment is represented by −log10 of (Benjamini corrected) P value. A more comprehensive account is provided in Supplementary Data 3 and 4. (i) Estimation of the developmental stage of 2 h AED embryos of bacterial-depleted flies (Decor.) and control embryos, based on transcriptome mapping to published time course data30. Blue and green traces display the average time course for sets of Maternal and Zygotic transcripts listed in Supplementary Data 2. Estimation and normalization was based on Efroni et al.39 using maternal genes as a reference. *P<0.05, ** P<0.01, *** P<0.001 (Student's t-test).
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f1: Lack of gut microbiota represses oogenesis and alters early embryonic development in the next generation.(a) Representative images of DAPI-stained ovaries at day 6 after eclosion, shown for untreated case (control) and for females developed from dechorionated eggs that were placed on food without bacteria (Dechor.) and food supplemented with single species of native Acetobacter (Dechor.+Aceto) or Lactobacillus (Dechor.+Lacto). Note the reduction in the size of the ovary and the number of mature oocytes without extracellular gut bacteria. (b) Number of oocytes per ovary and percentages of oocytes at stages 8–10 and 11–14 for the cases in a. Mean±s.e. based on three replicated experiments each with >20 ovaries. (c) Egg deposition over 4 h period relative to control. Mean fold-change ±s.e. based on three replicated experiments, each containing >20 females. (d) Total number of eggs deposited per female over a period of 5 days. Mean±s.e. based on three replicates, each with n>7. (e) Scatter plot of transcript levels (RPKM) in embryos of bacterial-depleted flies (Dechor.) versus control embryos (both at 2 h after egg deposition, ‘AED'). Each point represents average transcript levels based on 6 RNA-seq analyses per condition (three wild-type strains, each measured in duplicates). Blue and green overlays display maternal and zygotic transcripts selected based on Thomsen et al.29 and De-Renzis et al.31, respectively. (f) Global reduction in the levels of maternal transcripts and reciprocal increase in zygotic transcripts in 2 h AED embryos of bacterial-depleted flies versus control embryos. Maternal and zygotic transcripts were defined based on Lott et al.30. (g) Correlation between the half-life of maternal transcripts (based on ref. 29) and their extent of reduction in bacterial-depleted (Decor.) versus control embryos. (h) Representative enrichments of Gene Ontology (GO) annotations in groups of transcripts that were differentially expressed in 2 h AED embryos of bacterial-depleted flies compared to control embryos (pink and light blue) or to a stage-matched transcriptome (red and blue). Enrichment is represented by −log10 of (Benjamini corrected) P value. A more comprehensive account is provided in Supplementary Data 3 and 4. (i) Estimation of the developmental stage of 2 h AED embryos of bacterial-depleted flies (Decor.) and control embryos, based on transcriptome mapping to published time course data30. Blue and green traces display the average time course for sets of Maternal and Zygotic transcripts listed in Supplementary Data 2. Estimation and normalization was based on Efroni et al.39 using maternal genes as a reference. *P<0.05, ** P<0.01, *** P<0.001 (Student's t-test).

Mentions: We investigated the influence of extracellular gut bacteria on reproductive capacity of the fly by eliminating the bacteria using egg dechorionation and sterilization18. This led to substantial changes in the ovary (Fig. 1a,b), which included reduction in the number of oocytes per ovary and in the fraction of late-stage oocytes (Fig. 1b; Supplementary Fig. 1A). These changes were consistent with a strong reduction in egg deposition (Fig. 1c,d; Supplementary Fig. 1B). Similar results were observed in a Wolbachia-free fly strain (Oregon R), indicating that the repression of oogenesis and reproduction in bacterial-depleted flies is independent of Wolbachia (Supplementary Fig. 1A,B). Notably, the reduction in egg deposition did not compromise survival to adulthood of the deposited eggs (Supplementary Fig. 1C). Successful re-colonization of the larval gut with bacteria from an isolated Acetobacter species, Colony 1 (ref. 28) (Supplementary Fig. 1D), completely restored the oogenesis phenotypes (Fig. 1a–c). Similar rescue was observed when these bacteria were introduced in the adult stage (Supplementary Fig. 1E), indicating that the suppression of oogenesis in bacterial-depleted flies is reversible at any time and does not reflect irreversible failure of development. Recolonization of isolated Lactobacillus (Colony 7)28, on the other hand, led only to a partial rescue; it prevented the reduction in oocyte maturation, but not in the total number of eggs per ovary and egg deposition (Fig. 1b,c). qPCR-based analysis of bacterial content in the ovary of females with intact gut bacteria showed that Acetobacter and Lactobacillus spp. are not present in the ovary (Supplementary Fig. 1F), indicating that removal of gut bacteria impacts oogenesis from a remote location.


Impact of gut microbiota on the fly's germ line.

Elgart M, Stern S, Salton O, Gnainsky Y, Heifetz Y, Soen Y - Nat Commun (2016)

Lack of gut microbiota represses oogenesis and alters early embryonic development in the next generation.(a) Representative images of DAPI-stained ovaries at day 6 after eclosion, shown for untreated case (control) and for females developed from dechorionated eggs that were placed on food without bacteria (Dechor.) and food supplemented with single species of native Acetobacter (Dechor.+Aceto) or Lactobacillus (Dechor.+Lacto). Note the reduction in the size of the ovary and the number of mature oocytes without extracellular gut bacteria. (b) Number of oocytes per ovary and percentages of oocytes at stages 8–10 and 11–14 for the cases in a. Mean±s.e. based on three replicated experiments each with >20 ovaries. (c) Egg deposition over 4 h period relative to control. Mean fold-change ±s.e. based on three replicated experiments, each containing >20 females. (d) Total number of eggs deposited per female over a period of 5 days. Mean±s.e. based on three replicates, each with n>7. (e) Scatter plot of transcript levels (RPKM) in embryos of bacterial-depleted flies (Dechor.) versus control embryos (both at 2 h after egg deposition, ‘AED'). Each point represents average transcript levels based on 6 RNA-seq analyses per condition (three wild-type strains, each measured in duplicates). Blue and green overlays display maternal and zygotic transcripts selected based on Thomsen et al.29 and De-Renzis et al.31, respectively. (f) Global reduction in the levels of maternal transcripts and reciprocal increase in zygotic transcripts in 2 h AED embryos of bacterial-depleted flies versus control embryos. Maternal and zygotic transcripts were defined based on Lott et al.30. (g) Correlation between the half-life of maternal transcripts (based on ref. 29) and their extent of reduction in bacterial-depleted (Decor.) versus control embryos. (h) Representative enrichments of Gene Ontology (GO) annotations in groups of transcripts that were differentially expressed in 2 h AED embryos of bacterial-depleted flies compared to control embryos (pink and light blue) or to a stage-matched transcriptome (red and blue). Enrichment is represented by −log10 of (Benjamini corrected) P value. A more comprehensive account is provided in Supplementary Data 3 and 4. (i) Estimation of the developmental stage of 2 h AED embryos of bacterial-depleted flies (Decor.) and control embryos, based on transcriptome mapping to published time course data30. Blue and green traces display the average time course for sets of Maternal and Zygotic transcripts listed in Supplementary Data 2. Estimation and normalization was based on Efroni et al.39 using maternal genes as a reference. *P<0.05, ** P<0.01, *** P<0.001 (Student's t-test).
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Related In: Results  -  Collection

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f1: Lack of gut microbiota represses oogenesis and alters early embryonic development in the next generation.(a) Representative images of DAPI-stained ovaries at day 6 after eclosion, shown for untreated case (control) and for females developed from dechorionated eggs that were placed on food without bacteria (Dechor.) and food supplemented with single species of native Acetobacter (Dechor.+Aceto) or Lactobacillus (Dechor.+Lacto). Note the reduction in the size of the ovary and the number of mature oocytes without extracellular gut bacteria. (b) Number of oocytes per ovary and percentages of oocytes at stages 8–10 and 11–14 for the cases in a. Mean±s.e. based on three replicated experiments each with >20 ovaries. (c) Egg deposition over 4 h period relative to control. Mean fold-change ±s.e. based on three replicated experiments, each containing >20 females. (d) Total number of eggs deposited per female over a period of 5 days. Mean±s.e. based on three replicates, each with n>7. (e) Scatter plot of transcript levels (RPKM) in embryos of bacterial-depleted flies (Dechor.) versus control embryos (both at 2 h after egg deposition, ‘AED'). Each point represents average transcript levels based on 6 RNA-seq analyses per condition (three wild-type strains, each measured in duplicates). Blue and green overlays display maternal and zygotic transcripts selected based on Thomsen et al.29 and De-Renzis et al.31, respectively. (f) Global reduction in the levels of maternal transcripts and reciprocal increase in zygotic transcripts in 2 h AED embryos of bacterial-depleted flies versus control embryos. Maternal and zygotic transcripts were defined based on Lott et al.30. (g) Correlation between the half-life of maternal transcripts (based on ref. 29) and their extent of reduction in bacterial-depleted (Decor.) versus control embryos. (h) Representative enrichments of Gene Ontology (GO) annotations in groups of transcripts that were differentially expressed in 2 h AED embryos of bacterial-depleted flies compared to control embryos (pink and light blue) or to a stage-matched transcriptome (red and blue). Enrichment is represented by −log10 of (Benjamini corrected) P value. A more comprehensive account is provided in Supplementary Data 3 and 4. (i) Estimation of the developmental stage of 2 h AED embryos of bacterial-depleted flies (Decor.) and control embryos, based on transcriptome mapping to published time course data30. Blue and green traces display the average time course for sets of Maternal and Zygotic transcripts listed in Supplementary Data 2. Estimation and normalization was based on Efroni et al.39 using maternal genes as a reference. *P<0.05, ** P<0.01, *** P<0.001 (Student's t-test).
Mentions: We investigated the influence of extracellular gut bacteria on reproductive capacity of the fly by eliminating the bacteria using egg dechorionation and sterilization18. This led to substantial changes in the ovary (Fig. 1a,b), which included reduction in the number of oocytes per ovary and in the fraction of late-stage oocytes (Fig. 1b; Supplementary Fig. 1A). These changes were consistent with a strong reduction in egg deposition (Fig. 1c,d; Supplementary Fig. 1B). Similar results were observed in a Wolbachia-free fly strain (Oregon R), indicating that the repression of oogenesis and reproduction in bacterial-depleted flies is independent of Wolbachia (Supplementary Fig. 1A,B). Notably, the reduction in egg deposition did not compromise survival to adulthood of the deposited eggs (Supplementary Fig. 1C). Successful re-colonization of the larval gut with bacteria from an isolated Acetobacter species, Colony 1 (ref. 28) (Supplementary Fig. 1D), completely restored the oogenesis phenotypes (Fig. 1a–c). Similar rescue was observed when these bacteria were introduced in the adult stage (Supplementary Fig. 1E), indicating that the suppression of oogenesis in bacterial-depleted flies is reversible at any time and does not reflect irreversible failure of development. Recolonization of isolated Lactobacillus (Colony 7)28, on the other hand, led only to a partial rescue; it prevented the reduction in oocyte maturation, but not in the total number of eggs per ovary and egg deposition (Fig. 1b,c). qPCR-based analysis of bacterial content in the ovary of females with intact gut bacteria showed that Acetobacter and Lactobacillus spp. are not present in the ovary (Supplementary Fig. 1F), indicating that removal of gut bacteria impacts oogenesis from a remote location.

Bottom Line: Unlike vertically transmitted endosymbionts, which have broad effects on their host's germ line, the extracellular gut microbiota is transmitted horizontally and is not known to influence the germ line.We further show that the main impact on oogenesis is linked to the lack of gut Acetobacter species, and we identify the Drosophila Aldehyde dehydrogenase (Aldh) gene as an apparent mediator of repressed oogenesis in Acetobacter-depleted flies.The finding of interactions between the gut microbiota and the germ line has implications for reproduction, developmental robustness and adaptation.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.

ABSTRACT
Unlike vertically transmitted endosymbionts, which have broad effects on their host's germ line, the extracellular gut microbiota is transmitted horizontally and is not known to influence the germ line. Here we provide evidence supporting the influence of these gut bacteria on the germ line of Drosophila melanogaster. Removal of the gut bacteria represses oogenesis, expedites maternal-to-zygotic-transition in the offspring and unmasks hidden phenotypic variation in mutants. We further show that the main impact on oogenesis is linked to the lack of gut Acetobacter species, and we identify the Drosophila Aldehyde dehydrogenase (Aldh) gene as an apparent mediator of repressed oogenesis in Acetobacter-depleted flies. The finding of interactions between the gut microbiota and the germ line has implications for reproduction, developmental robustness and adaptation.

No MeSH data available.


Related in: MedlinePlus