Microbiome - HH-RA.org

Bibliography Tag: microbiome

Zhao et al., 2016

Zhao, Y., Zhang, Y., Wang, G., Han, R., & Xie, X.; “Effects of chlorpyrifos on the gut microbiome and urine metabolome in mouse (Mus musculus);” Chemosphere, 2016, 153, 287-293; DOI: 10.1016/j.chemosphere.2016.03.055.

ABSTRACT:

In this study, the toxic effects of chlorpyrifos (CPF) on the gut microbiome and related urine metabolome in mouse (Mus musculus) were investigated. Mice were exposed to a daily dose of 1 mg kg(-1) bodyweight of CPF for 30 d. As a result, CPF significantly altered the gut microbiota composition in terms of the relative abundance of key microbes. Meanwhile, CPF exposure induced the alterations of urine metabolites related to the metabolism of amino acids, energy, short-chain fatty acids (SCFAs), phenyl derivatives and bile acids. High correlations were observed between perturbed gut microbiome and altered metabolic profiles. These perturbations finally resulted in intestinal inflammation and abnormal intestinal permeability, which were also confirm by the histologic changes in colon and remarkable increase of lipopolysaccharide (LPS) and diamine oxidase (DAO) in the serum of CPF-treated mice. Our findings will provide a new perspective to reveal the mechanism of CPF toxicity. FULL TEXT

Hantsoo et al., 2019

Hantsoo, L., Jasarevic, E., Criniti, S., McGeehan, B., Tanes, C., Sammel, M. D., Elovitz, M. A., Compher, C., Wu, G., & Epperson, C. N.; “Childhood adversity impact on gut microbiota and inflammatory response to stress during pregnancy;” Brain, Behavior, and Immunity, 2019, 75, 240-250; DOI: 10.1016/j.bbi.2018.11.005.

ABSTRACT:

BACKGROUND: Adverse childhood experiences (ACEs), such as abuse or chronic stress, program an exaggerated adult inflammatory response to stress. Emerging rodent research suggests that the gut microbiome may be a key mediator in the association between early life stress and dysregulated glucocorticoid-immune response. However, ACE impact on inflammatory response to stress, or on the gut microbiome, have not been studied in human pregnancy, when inflammation increases risk of poor outcomes. The aim of this study was to assess the relationships among ACE, the gut microbiome, and cytokine response to stress in pregnant women.

METHODS: Physically and psychiatrically healthy adult pregnant women completed the Adverse Childhood Experiences Questionnaire (ACE-Q) and gave a single stool sample between 20 and 26weeks gestation. Stool DNA was isolated and 16S sequencing was performed. Three 24-hour food recalls were administered to assess dietary nutrient intake. A subset of women completed the Trier Social Stress Test (TSST) at 22-34weeks gestation; plasma interleukin-6 (IL-6), interleukin-1beta (IL-1beta), high sensitivity C-reactive protein (hsCRP), tumor necrosis factor alpha (TNF-alpha), and cortisol were measured at four timepoints pre and post stressor, and area under the curve (AUC) was calculated.

RESULTS: Forty-eight women completed the ACE-Q and provided stool; 19 women completed the TSST. Women reporting 2 or more ACEs (high ACE) had greater differential abundance of gut Prevotella than low ACE participants (q=5.7×10^-13). Abundance of several gut taxa were significantly associated with cortisol, IL-6, TNF-alpha and CRP AUCs regardless of ACE status. IL-6 response to stress was buffered among high ACE women with high intake of docosahexaenoic acid (DHA) (p=0.03) and eicosapentaenoic acid (EPA) (p=0.05).

DISCUSSION: Our findings suggest that multiple childhood adversities are associated with changes in gut microbiota composition during pregnancy, and such changes may contribute to altered inflammatory and glucocorticoid response to stress. While preliminary, this is the first study to demonstrate an association between gut microbiota and acute glucocorticoid-immune response to stress in a clinical sample. Finally, exploratory analyses suggested that high ACE women with high dietary intake of omega-3 polyunsaturated fatty acids (PUFAs) had a dampened inflammatory response to acute stress, suggesting potentially protective effects of omega-3s in this high-risk population. Given the adverse effects of inflammation on pregnancy and the developing fetus, mechanisms by which childhood adversity influence the gut-brain axis and potential protective factors such as diet should be further explored.

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Mesnage and Antoniou, 2020

Mesnage, Robin, & Antoniou, Michael N.; “Computational modelling provides insight into the effects of glyphosate on the shikimate pathway in the human gut microbiome;” Current Research in Toxicology, 2020, 1, 25-33; DOI: 10.1016/j.crtox.2020.04.001.

ABSTRACT:

The herbicide active ingredient glyphosate can affect the growth of microorganisms, which rely on the shikimate pathway for aromatic amino acid biosynthesis. However, it is uncertain whether glyphosate exposure could lead to perturbations in the population of human gut microbiota. We have addressed this knowledge gap by analysing publicly available datasets to provide new insights into possible effects of glyphosate on the human gut microbiome. Comparison of the abundance of the shikimate pathway in 734 paired metagenomes and metatranscriptomes indicated that most gut bacteria do not possess a complete shikimate pathway, and that this pathway is mostly transcriptionally inactive in the human gut microbiome. This suggests that gut bacteria are mostly aromatic amino acid auxotrophs and thus relatively resistant to a potential growth inhibition by glyphosate. As glyphosate blocking of the shikimate pathway is via inhibition of EPSPS, we classified E. coli EPSPS enzyme homologues as class I (sensitive to glyphosate) and class II (resistant to glyphosate). Among 44 subspecies reference genomes, accounting for 72% of the total assigned microbial abundance in 2144 human faecal metagenomes, 9 subspecies have class II EPSPS. The study of publicly available gut metagenomes also indicated that glyphosate might be degraded by some Proteobacteria in the human gut microbiome using the carbon–phosphorus lyase pathway. Overall, there is limited experimental evidence available for the effects of glyphosate on the human gut microbiome. Further investigations using more advanced molecular profiling techniques are needed to ascertain whether glyphosate and glyphosate-based herbicides can alter the function of the gut microbiome with consequent health implications. FULL TEXT

Dechartres et al., 2019

Dechartres, J., Pawluski, J. L., Gueguen, M. M., Jablaoui, A., Maguin, E., Rhimi, M., & Charlier, T. D.; “Glyphosate and glyphosate-based herbicide exposure during the peripartum period affects maternal brain plasticity, maternal behaviour and microbiome;” Journal of Neuroendocrinology, 2019, 31(9), e12731; DOI: 10.1111/jne.12731.

ABSTRACT:

Glyphosate is found in a large array of non-selective herbicides such as Roundup(R) (Monsanto, Creve Coeur, MO, USA) and is by far the most widely used herbicide. Recent work in rodent models suggests that glyphosate-based herbicides during development can affect neuronal communication and result in altered behaviours, albeit through undefined mechanisms of action. To our knowledge, no study has investigated the effects glyphosate or its formulation in herbicide on maternal behaviour and physiology. In the present study, relatively low doses of glyphosate (5 mg kg(-1) d(-1) ), Roundup(R) (5 mg kg(-1) d(-1) glyphosate equivalent), or vehicle were administered by ingestion to Sprague-Dawley rats from gestational day (GD) 10 to postpartum day (PD)22. The treatments significantly altered licking behaviour toward pups between PD2 and PD6. We also show in the dams at PD22 that Roundup exposure affected the maturation of doublecortin-immunoreactive new neurones in the dorsal dentate gyrus of the hippocampus of the mother. In addition, the expression of synaptophysin was up-regulated by glyphosate in the dorsal and ventral dentate gyrus and CA3 regions of the hippocampus, and down-regulated in the cingulate gyrus. Although a direct effect of glyphosate alone or its formulation on the central nervous system is currently not clear, we show that gut microbiota is significantly altered by the exposure to the pesticides, with significant alteration of the phyla Bacteroidetes and Firmicutes. This is the first study to provide evidence that glyphosate alone or in formulation (Roundup) differentially affects maternal behaviour and modulates neuroplasticity and gut microbiota in the mother. FULL TEXT

Wang et al., 2020

Wang, G. H., Berdy, B. M., Velasquez, O., Jovanovic, N., Alkhalifa, S., Minbiole, K. P. C., & Brucker, R. M.; “Changes in Microbiome Confer Multigenerational Host Resistance after Sub-toxic Pesticide Exposure;” Cell Host & Microbe, 2020; DOI: 10.1016/j.chom.2020.01.009.

ABSTRACT:

The gut is a first point of contact with ingested xenobiotics, where chemicals are metabolized directly by the host or microbiota. Atrazine is a widely used pesticide, but the role of the microbiome metabolism of this xenobiotic and the impact on host responses is unclear. We exposed successive generations of the wasp Nasonia vitripennis to subtoxic levels of atrazine and observed changes in the structure and function of the gut microbiome that conveyed atrazine resistance. This microbiome-mediated resistance was maternally inherited and increased over successive generations, while also heightening the rate of host genome selection. The rare gut bacteria Serratia marcescens and Pseudomonas protegens contributed to atrazine metabolism. Both of these bacteria contain genes that are linked to atrazine degradation and were sufficient to confer resistance in experimental wasp populations. Thus, pesticide exposure causes functional, inherited changes in the microbiome that should be considered when assessing xenobiotic exposure and as potential countermeasures to toxicity. FULL TEXT

Perro, 2019

Perro, Michelle, “Childhood Leukemia, the Microbiome, and Glyphosate: A Doctor’s Perspective,” GMOScience.org, January 15, 2019.

SUMMARY:

Childhood leukemia is on the rise
Exposure to pesticides is known to increase the risk of childhood leukemia, as well as other types of cancer
New research links an impoverished gut microbiome (bacterial community) and chronic inflammation with increased risk of childhood leukemia
Diet-related ways are being sought to improve the microbiome and prevent the inflammation that triggers childhood leukemia
Glyphosate herbicides are used on around 90% of GM crops; glyphosate has been classified as a probable carcinogen by the World Health Organization’s cancer agency IARC
Exposure to glyphosate-based and other pesticides has been shown to disrupt the gut microbiome in laboratory animals
People who eat organic food have been found to have a 25% reduced risk of cancer
Clinical experience shows that switching to an organic and non-GMO diet improves people’s health
Controlled studies are needed to verify how switching to an organic and non-GMO diet affects the microbiome and certain disease conditions.

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Perro and Adams, 2017

Perro, Michelle and Adams, Vincanne, “What’s Making Our Children Sick? How Industrial Food Is Causing an Epidemic of Chronic Illness, and What Parents (and Doctors) Can Do About It,” Chelsea Green Publishing, 2017.

SUMMARY:

With chronic disorders among American children reaching epidemic levels, hundreds of thousands of parents are desperately seeking solutions to their children’s declining health, often with little medical guidance from the experts. What’s Making Our Children Sick? convincingly explains how agrochemical industrial production and genetic modification of foods is a culprit in this epidemic. Is it the only culprit? No. Most chronic health disorders have multiple causes and require careful disentanglement and complex treatments. But what if toxicants in our foods are a major culprit, one that, if corrected, could lead to tangible results and increased health? Using patient accounts of their clinical experiences and new medical insights about pathogenesis of chronic pediatric disorders—taking us into gut dysfunction and the microbiome, as well as the politics of food science—this book connects the dots to explain our kids’ ailing health.

What’s Making Our Children Sick? explores the frightening links between our efforts to create higher-yield, cost-efficient foods and an explosion of childhood morbidity, but it also offers hope and a path to effecting change. The predicament we now face is simple. Agroindustrial “innovation” in a previous era hoped to prevent the ecosystem disaster of DDT predicted in Rachel Carson’s seminal book in 1962, Silent Spring. However, this industrial agriculture movement has created a worse disaster: a toxic environment and, consequently, a toxic food supply. Pesticide use is at an all-time high, despite the fact that biotechnologies aimed to reduce the need for them in the first place. Today these chemicals find their way into our livestock and food crop industries and ultimately onto our plates. Many of these pesticides are the modern day equivalent of DDT. However, scant research exists on the chemical soup of poisons that our children consume on a daily basis. As our food supply environment reels under the pressures of industrialization via agrochemicals, our kids have become the walking evidence of this failed experiment. What’s Making Our Children Sick? exposes our current predicament and offers insight on the medical responses that are available, both to heal our kids and to reverse the compromised health of our food supply.

Sherwin et al., 2019

Sherwin, E., Bordenstein, S. R., Quinn, J. L., Dinan, T. G., & Cryan, J. F.; “Microbiota and the social brain;” Science, 2019, 366(6465); DOI: 10.1126/science.aar2016.

ABSTRACT:

Sociability can facilitate mutually beneficial outcomes such as division of labor, cooperative care, and increased immunity, but sociability can also promote negative outcomes, including aggression and coercion. Accumulating evidence suggests that symbiotic microorganisms, specifically the microbiota that reside within the gastrointestinal system, may influence neurodevelopment and programming of social behaviors across diverse animal species. This relationship between host and microbes hints that host-microbiota interactions may have influenced the evolution of social behaviors. Indeed, the gastrointestinal microbiota is used by certain species as a means to facilitate communication among conspecifics. Further understanding of how microbiota influence the brain in nature may be helpful for elucidating the causal mechanisms underlying sociability and for generating new therapeutic strategies for social disorders in humans, such as autism spectrum disorders (ASDs). FULL TEXT

Daisley et al., 2018

Daisley, B. A., Trinder, M., McDowell, T. W., Collins, S. L., Sumarah, M. W., & Reid, G.; “Microbiota-Mediated Modulation of Organophosphate Insecticide Toxicity by Species-Dependent Interactions with Lactobacilli in a Drosophila melanogaster Insect Model;” Applied and Environmental Microbiology, 2018, 84(9); DOI: 10.1128/AEM.02820-17.

ABSTRACT:

Despite the benefits to the global food supply and agricultural economies, pesticides are believed to pose a threat to the health of both humans and wildlife. Chlorpyrifos (CP), a commonly used organophosphate insecticide, has poor target specificity and causes acute neurotoxicity in a wide range of species via the suppression of acetylcholinesterase. This effect is exacerbated 10- to 100-fold by chlorpyrifos oxon (CPO), a principal metabolite of CP. Since many animal-associated symbiont microorganisms are known to hydrolyze CP into CPO, we used a Drosophila melanogaster insect model to investigate the hypothesis that indigenous and probiotic bacteria could affect CP metabolism and toxicity. Antibiotic-treated and germfree D. melanogaster insects lived significantly longer than their conventionally reared counterparts when exposed to 10 muM CP. Drosophila melanogaster gut-derived Lactobacillus plantarum, but not Acetobacterindonesiensis, was shown to metabolize CP. Liquid chromatography tandem-mass spectrometry confirmed that the L. plantarum isolate preferentially metabolized CP into CPO when grown in CP-spiked culture medium. Further experiments showed that monoassociating germfree D. melanogaster with the L. plantarum isolate could reestablish a conventional-like sensitivity to CP. Interestingly, supplementation with the human probiotic Lactobacillus rhamnosus GG (a strain that binds but does not metabolize CP) significantly increased the survival of the CP-exposed germfree D. melanogaster This suggests strain-specific differences in CP metabolism may exist among lactobacilli and emphasizes the need for further investigation. In summary, these results suggest that (i) CPO formation by the gut microbiota can have biologically relevant consequences for the host, and (ii) probiotic lactobacilli may be beneficial in reducing in vivo CP toxicity.IMPORTANCE An understudied area of research is how the microbiota (microorganisms living in/on an animal) affects the metabolism and toxic outcomes of environmental pollutants such as pesticides. This study focused specifically on how the microbial biotransformation of chlorpyrifos (CP; a common organophosphate insecticide) affected host exposure and toxicity parameters in a Drosophila melanogaster insect model. Our results demonstrate that the biotransformation of CP by the gut microbiota had biologically relevant and toxic consequences on host health and that certain probiotic lactobacilli may be beneficial in reducing CP toxicity. Since inadvertent pesticide exposure is suspected to negatively impact the health of off-target species, these findings may provide useful information for wildlife conservation and environmental sustainability planning. Furthermore, the results highlight the need to consider microbiota composition differences between beneficial and pest insects in future insecticide designs. More broadly, this study supports the use of beneficial microorganisms to modulate the microbiota-mediated biotransformation of xenobiotics. FULL TEXT

Xia et al., 2018

Xia, X., Sun, B., Gurr, G. M., Vasseur, L., Xue, M., & You, M.; “Gut Microbiota Mediate Insecticide Resistance in the Diamondback Moth, Plutella xylostella (L.);” Frontiers in Microbiology, 2018, 9, 25; DOI: 10.3389/fmicb.2018.00025.

ABSTRACT:

The development of insecticide resistance in insect pests is a worldwide concern and elucidating the underlying mechanisms is critical for effective crop protection. Recent studies have indicated potential links between insect gut microbiota and insecticide resistance and these may apply to the diamondback moth, Plutella xylostella (L.), a globally and economically important pest of cruciferous crops. We isolated Enterococcus sp. (Firmicutes), Enterobacter sp. (Proteobacteria), and Serratia sp. (Proteobacteria) from the guts of P. xylostella and analyzed the effects on, and underlying mechanisms of insecticide resistance. Enterococcus sp. enhanced resistance to the widely used insecticide, chlorpyrifos, in P. xylostella, while in contrast, Serratia sp. decreased resistance and Enterobacter sp. and all strains of heat-killed bacteria had no effect. Importantly, the direct degradation of chlorpyrifos in vitro was consistent among the three strains of bacteria. We found that Enterococcus sp., vitamin C, and acetylsalicylic acid enhanced insecticide resistance in P. xylostella and had similar effects on expression of P. xylostella antimicrobial peptides. Expression of cecropin was down-regulated by the two compounds, while gloverin was up-regulated. Bacteria that were not associated with insecticide resistance induced contrasting gene expression profiles to Enterococcus sp. and the compounds. Our studies confirmed that gut bacteria play an important role in P. xylostella insecticide resistance, but the main mechanism is not direct detoxification of insecticides by gut bacteria. We also suggest that the influence of gut bacteria on insecticide resistance may depend on effects on the immune system. Our work advances understanding of the evolution of insecticide resistance in this key pest and highlights directions for research into insecticide resistance in other insect pest species. FULL TEXT

Bibliography Index