Browsing by Author "Bletz, Molly C."

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    Arthropod-bacteria interactions influence assembly of aquatic host microbiome and pathogen defense
    (Royal Society of London, 2019) Greenspan, Sasha E.; Lyra, Mariana L.; Migliorini, Gustavo H.; Kersch-Becker, Monica F.; Bletz, Molly C.; Lisboa, Cybele Sabino; Pontes, Mariana R.; Ribeiro, Luisa P.; Neely, Wesley J.; Rezende, Felipe; Romero, Gustavo Q.; Woodhams, Douglas C.; Haddad, Celio F. B.; Toledo, Luis Felipe; Becker, C. Guilherme; University of Alabama Tuscaloosa; Universidade Estadual Paulista; University of Massachusetts Boston; Universidade Estadual de Campinas
    The host-associated microbiome is vital to host immunity and pathogen defense. In aquatic ecosystems, organisms may interact with environmental bacteria to influence the pool of potential symbionts, but the effects of these interactions on host microbiome assembly and pathogen resistance are unresolved. We used replicated bromeliad microecosystems to test for indirect effects of arthropod-bacteria interactions on host microbiome assembly and pathogen burden, using tadpoles and the fungal amphibian pathogen Batrachochytrium dendrobatidis as a model host-pathogen system. Arthropods influenced host microbiome assembly by altering the pool of environmental bacteria, with arthropod-bacteria interactions specifically reducing host colonization by transient bacteria and promoting antimicrobial components of aquatic bacterial communities. Arthropods also reduced fungal zoospores in the environment, but fungal infection burdens in tadpoles corresponded most closely with arthropod-mediated patterns in microbiome assembly. This result indicates that the cascading effects of arthropods on the maintenance of a protective host microbiome may be more strongly linked to host health than negative effects of arthropods on pools of pathogenic zoospores. Our work reveals tight links between healthy ecosystem dynamics and the functioning of host microbiomes, suggesting that ecosystem disturbances such as loss of arthropods may have downstream effects on host-associated microbial pathogen defenses and host fitness.
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    Host-associated microbiomes are predicted by immune system complexity and climate
    (BMC, 2020) Woodhams, Douglas C.; Bletz, Molly C.; Becker, C. Guilherme; Bender, Hayden A.; Buitrago-Rosas, Daniel; Diebboll, Hannah; Huynh, Roger; Kearns, Patrick J.; Kueneman, Jordan; Kurosawa, Emmi; LaBumbard, Brandon C.; Lyons, Casandra; McNally, Kerry; Schliep, Klaus; Shankar, Nachiket; Tokash-Peters, Amanda G.; Vences, Miguel; Whetstone, Ross; University of Massachusetts Boston; Smithsonian Institution; Smithsonian Tropical Research Institute; University of Alabama Tuscaloosa; University of Rwanda; Braunschweig University of Technology
    Background Host-associated microbiomes, the microorganisms occurring inside and on host surfaces, influence evolutionary, immunological, and ecological processes. Interactions between host and microbiome affect metabolism and contribute to host adaptation to changing environments. Meta-analyses of host-associated bacterial communities have the potential to elucidate global-scale patterns of microbial community structure and function. It is possible that host surface-associated (external) microbiomes respond more strongly to variations in environmental factors, whereas internal microbiomes are more tightly linked to host factors. Results Here, we use the dataset from the Earth Microbiome Project and accumulate data from 50 additional studies totaling 654 host species and over 15,000 samples to examine global-scale patterns of bacterial diversity and function. We analyze microbiomes from non-captive hosts sampled from natural habitats and find patterns with bioclimate and geophysical factors, as well as land use, host phylogeny, and trophic level/diet. Specifically, external microbiomes are best explained by variations in mean daily temperature range and precipitation seasonality. In contrast, internal microbiomes are best explained by host factors such as phylogeny/immune complexity and trophic level/diet, plus climate. Conclusions Internal microbiomes are predominantly associated with top-down effects, while climatic factors are stronger determinants of microbiomes on host external surfaces. Host immunity may act on microbiome diversity through top-down regulation analogous to predators in non-microbial ecosystems. Noting gaps in geographic and host sampling, this combined dataset represents a global baseline available for interrogation by future microbial ecology studies.
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    Host-associated microbiomes are predicted by immune system complexity and climate (vol 21, 23, 2020)
    (BMC, 2020) Woodhams, Douglas C.; Bletz, Molly C.; Becker, C. Guilherme; Bender, Hayden A.; Buitrago-Rosas, Daniel; Diebboll, Hannah; Huynh, Roger; Kearns, Patrick J.; Kueneman, Jordan; Kurosawa, Emmi; LaBumbard, Brandon C.; Lyons, Casandra; McNally, Kerry; Schliep, Klaus; Shankar, Nachiket; Tokash-Peters, Amanda G.; Vences, Miguel; Whetstone, Ross; University of Massachusetts Boston; Smithsonian Institution; Smithsonian Tropical Research Institute; University of Alabama Tuscaloosa; University of Rwanda; Braunschweig University of Technology
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    Low -load pathogen spillover predicts shifts in skin microbiome and survival of a terrestrial-breeding amphibian
    (Royal Society of London, 2019) Becker, C. Guilherme; Bletz, Molly C.; Greenspan, Sasha E.; Rodriguez, David; Lambertini, Carolina; Jenkinson, Thomas S.; Guimaraes, Paulo R., Jr.; Assis, Ana Paula A.; Geffers, Robert; Jarek, Michael; Toledo, Luis Felipe; Vences, Miguel; Haddad, Celio F. B.; University of Alabama Tuscaloosa; University of Massachusetts Boston; Texas State University San Marcos; Universidade Estadual de Campinas; University of California Berkeley; Universidade de Sao Paulo; Helmholtz Association; Helmholtz-Center for Infection Research; Braunschweig University of Technology; Universidade Estadual Paulista
    Wildlife disease dynamics are strongly influenced by the structure of host communities and their symbiotic microbiota. Conspicuous amphibian declines associated with the waterborne fungal pathogen Batrachochytrium dendrobatidis (Bd) have been observed in aquatic-breeding frogs globally. However, less attention has been given to cryptic terrestrial-breeding amphibians that have also been declining in tropical regions. By experimentally manipulating multiple tropical amphibian assemblages harbouring natural microbial communities, we tested whether Bd spillover from naturally infected aquatic-breeding frogs could lead to Bd amplification and mortality in our focal terrestrial-breeding host: the pumpkin toadlet Brachycephalus pitanga. We also tested whether the strength of spillover could vary depending on skin bacterial transmission within host assemblages. Terrestrial-breeding toadlets acquired lethal spillover infections from neighbouring aquatic hosts and experienced dramatic but generally non protective shifts in skin bacterial composition primarily attributable to their Bd infections. By contrast, aquatic-bleeding amphibians maintained mild Bd infections and higher survival, with shifts in bacterial microbiomes that were unrelated to Bd infections. Our results indicate that Bd spillover from even mildly infected aquatic-breeding hosts may lead to dysbiosis and mortality in terrestrial-breeding species, underscoring the need to further investigate recent population declines of terrestrial-breeding amphibians in the tropics.