Real-time molecular monitoring of chemical environment in obligate anaerobes during oxygen adaptive response

Holman, Hoi‐Ying N.; Wozei, Eleanor; Zhang, Lin; Comolli, Luis R.; Borglin, Sharon; Hazen, Terry C.; Downing, Kenneth H.

doi:10.1073/pnas.0902070106

Cited by 37 publications

(34 citation statements)

References 51 publications

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“…As expected, there was no growth of D. vulgaris in single culture, in GY medium, as D. vulgaris cannot grow on glucose or other hexoses, because of lack of permeases 18 . Survival of D. vulgaris in single culture in GY medium can be explained by its capacity to accumulate and to use polyglucose and elemental sulfur particles when necessary 19 . Its capacity to use sulfur particles was confirmed by the production of H 2 S at a concentration of 0.15 mM (at the end of the exponential phase), higher than that of 0.035 mM sulfate derived from the inorganic nutrients and yeast extract present in the GY medium.…”

Section: Resultsmentioning

confidence: 99%

Nutritional stress induces exchange of cell material and energetic coupling between bacterial species

et al. 2015

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Knowledge of the behaviour of bacterial communities is crucial for understanding biogeochemical cycles and developing environmental biotechnology. Here we demonstrate the formation of an artificial consortium between two anaerobic bacteria, Clostridium acetobutylicum (Gram-positive) and Desulfovibrio vulgaris Hildenborough (Gram-negative, sulfate-reducing) in which physical interactions between the two partners induce emergent properties. Molecular and cellular approaches show that tight cell-cell interactions are associated with an exchange of molecules, including proteins, which allows the growth of one partner (D. vulgaris) in spite of the shortage of nutrients. This physical interaction induces changes in expression of two genes encoding enzymes at the pyruvate crossroads, with concomitant changes in the distribution of metabolic fluxes, and allows a substantial increase in hydrogen production without requiring genetic engineering. The stress induced by the shortage of nutrients of D. vulgaris appears to trigger the interaction.

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Section: Resultsmentioning

confidence: 99%

Nutritional stress induces exchange of cell material and energetic coupling between bacterial species

et al. 2015

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“…PCL is a thermoplastic semi-crystalline polyester which contains five non-polar methylene groups and one polar ester group per chain link, and itis characterized by a broad band at ~ 2850 cm -1 for stretching vibration of methyl and methylene, and the band at ~ 1750 cm -1 signifies stretching vibration of carbonyl [31]. Post gyration, the typical absorption peaks of PCL could still be seen in all of them ( Figure 9) and details are given in Table 6.…”

Section: Molecular Structurementioning

confidence: 99%

Beads, beaded-fibres and fibres: Tailoring the morphology of poly(caprolactone) using pressurised gyration

Hong

Edirisinghe

Muthusubramanian

2016

Materials Science and Engineering: C

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This work focuses on forming bead on string poly(caprolactone) (PCL) by using gyration under pressure. The fibre morphology of bead on string is an interesting feature that falls between bead-free fibres and droplets, and it could be effectively controlled by the rheological properties of spinning dopes and the major processing parameters of the pressurised gyration system which are working pressure and rotating speed. Bead products were not always spherical in shape and tender to be more elliptical, therefore both their width and length were measured. The average bead width and length produced spanned a range 145 -660µm and 140 -1060µm, respectively. The average distance between two adjacent beads (i.e. inter-bead distance) and the bead size (width and length) are shown to be a function of processing parameters and polymer concentration. An interesting morphology i.e. beads with short fibre was observed when using a high polymer concentration. Bead on string structure agglomeration was promoted by a low polymer concentration. Formation of droplets or agglomerated bead on string is promoted below 5wt% polymer concentration, and beads with short fibre were present in the microstructure beyond a polymer concentration of 20 wt%.

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“…SR-FTIR takes advantage of three technologies: (i) the well-known sensitivity of infrared spectroscopy to the bond vibration frequencies in a molecule for determining molecular functional groups, (ii) the convenience of a light microscope to locate areas for molecular and composition analysis, and (iii) the 100-to 1000-fold increase in signal-to-noise provided by a bright SR-based infrared light source. Using photons in the mid-infrared region (B2.5 to B15.5 mm wavelength, or B4000 to B650 wavenumber in cm À 1 ), SR-FTIR spectromicroscopy has been successfully used to characterize microbial activities in geological materials and in both hydrated and dried biofilms (Holman et al, 2009;Hazen et al, 2010;Holman et al, 2010), in spite of the limitation that some signals may be ambiguous.…”

Section: Molecular Analysis Controlsmentioning

confidence: 99%

Tackling the minority: sulfate-reducing bacteria in an archaea-dominated subsurface biofilm

et al. 2012

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Archaea are usually minor components of a microbial community and dominated by a large and diverse bacterial population. In contrast, the SM1 Euryarchaeon dominates a sulfidic aquifer by forming subsurface biofilms that contain a very minor bacterial fraction (5%). These unique biofilms are delivered in high biomass to the spring outflow that provides an outstanding window to the subsurface. Despite previous attempts to understand its natural role, the metabolic capacities of the SM1 Euryarchaeon remain mysterious to date. In this study, we focused on the minor bacterial fraction in order to obtain insights into the ecological function of the biofilm. We link phylogenetic diversity information with the spatial distribution of chemical and metabolic compounds by combining three different state-of-the-art methods: PhyloChip G3 DNA microarray technology, fluorescence in situ hybridization (FISH) and synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectromicroscopy. The results of PhyloChip and FISH technologies provide evidence for selective enrichment of sulfate-reducing bacteria, which was confirmed by the detection of bacterial dissimilatory sulfite reductase subunit B (dsrB) genes via quantitative PCR and sequence-based analyses. We further established a differentiation of archaeal and bacterial cells by SR-FTIR based on typical lipid and carbohydrate signatures, which demonstrated a co-localization of organic sulfate, carbonated mineral and bacterial signatures in the biofilm. All these results strongly indicate an involvement of the SM1 euryarchaeal biofilm in the global cycles of sulfur and carbon and support the hypothesis that sulfidic springs are important habitats for Earth's energy cycles. Moreover, these investigations of a bacterial minority in an Archaea-dominated environment are a remarkable example of the great power of combining highly sensitive microarrays with label-free infrared imaging.

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Real-time molecular monitoring of chemical environment in obligate anaerobes during oxygen adaptive response

Cited by 37 publications

References 51 publications

Nutritional stress induces exchange of cell material and energetic coupling between bacterial species

Nutritional stress induces exchange of cell material and energetic coupling between bacterial species

Beads, beaded-fibres and fibres: Tailoring the morphology of poly(caprolactone) using pressurised gyration

Tackling the minority: sulfate-reducing bacteria in an archaea-dominated subsurface biofilm

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