Bosak Tanja

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Bosak
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Tanja
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  • Preprint
    Consumption of atmospheric hydrogen during the life cycle of soil-dwelling actinobacteria
    ( 2013-10) Meredith, Laura K. ; Rao, Deepa ; Bosak, Tanja ; Klepac-Ceraj, Vanja ; Tada, Kendall R. ; Hansel, Colleen M. ; Ono, Shuhei ; Prinn, Ronald G.
    Microbe-mediated soil uptake is the largest and most uncertain variable in the budget of atmospheric hydrogen (H2). The diversity and ecophysiological role of soil microorganisms that can consume low atmospheric abundances of H2 with high-affinity [NiFe]-hydrogenases is unknown. We expanded the library of atmospheric H2-consuming strains to include four soil Harvard Forest Isolate (HFI) Streptomyces spp., Streptomyces cattleya, and Rhodococcus equi by assaying for high-affinity hydrogenase (hhyL) genes and quantifying H2 uptake rates. We find that aerial structures (hyphae and spores) are important for Streptomyces H2 consumption; uptake was not observed in Streptomyces griseoflavus Tu4000 (deficient in aerial structures) and was reduced by physical disruption of Streptomyces sp. HFI8 aerial structures. H2 consumption depended on the life cycle stage in developmentally distinct actinobacteria: Streptomyces sp. HFI8 (sporulating) and R. equi (non-sporulating, non-filamentous). Strain HFI8 took up H2 only after forming aerial hyphae and sporulating, while R. equi only consumed H2 in the late exponential and stationary phase. These observations suggest that conditions favoring H2 uptake by actinobacteria are associated with energy and nutrient limitation. Thus, H2 may be an important energy source for soil microorganisms inhabiting systems in which nutrients are frequently limited.
  • Article
    Microbial functional diversity across biogeochemical provinces in the central Pacific Ocean
    (National Academy of Sciences, 2022-09-13) Saunders, Jaclyn K. ; McIlvin, Matthew R. ; Dupont, Christopher L. ; Kaul, Drishti ; Moran, Dawn M. ; Horner, Tristan J. ; Laperriere, Sarah ; Webb, Eric A. ; Bosak, Tanja ; Santoro, Alyson E. ; Saito, Mak A.
    Enzymes catalyze key reactions within Earth’s life-sustaining biogeochemical cycles. Here, we use metaproteomics to examine the enzymatic capabilities of the microbial community (0.2 to 3 µm) along a 5,000-km-long, 1-km-deep transect in the central Pacific Ocean. Eighty-five percent of total protein abundance was of bacterial origin, with Archaea contributing 1.6%. Over 2,000 functional KEGG Ontology (KO) groups were identified, yet only 25 KO groups contributed over half of the protein abundance, simultaneously indicating abundant key functions and a long tail of diverse functions. Vertical attenuation of individual proteins displayed stratification of nutrient transport, carbon utilization, and environmental stress. The microbial community also varied along horizontal scales, shaped by environmental features specific to the oligotrophic North Pacific Subtropical Gyre, the oxygen-depleted Eastern Tropical North Pacific, and nutrient-rich equatorial upwelling. Some of the most abundant proteins were associated with nitrification and C1 metabolisms, with observed interactions between these pathways. The oxidoreductases nitrite oxidoreductase (NxrAB), nitrite reductase (NirK), ammonia monooxygenase (AmoABC), manganese oxidase (MnxG), formate dehydrogenase (FdoGH and FDH), and carbon monoxide dehydrogenase (CoxLM) displayed distributions indicative of biogeochemical status such as oxidative or nutritional stress, with the potential to be more sensitive than chemical sensors. Enzymes that mediate transformations of atmospheric gases like CO, CO2, NO, methanethiol, and methylamines were most abundant in the upwelling region. We identified hot spots of biochemical transformation in the central Pacific Ocean, highlighted previously understudied metabolic pathways in the environment, and provided rich empirical data for biogeochemical models critical for forecasting ecosystem response to climate change.