Microbial metabolism is the engine that drives global biogeochemical cycles, yet many key transformations are carried out by microbial consortia over short spatiotemporal scales that elude detection by traditional analytical approaches. We investigate syntrophic sulfur cycling in the 'pink berry' consortia of the Sippewissett Salt Marsh through an integrative study at the microbial scale. The p...

The precursor relationship of cystathionine in the biosynthesis of methionine by Neurospora crassa was first indicated by Horowitz (1947). Isotope competition studies with N. crassa yielded evidence that the sulfur of cystathionine can supply a large portion of the sulfur needed for growth (Roberts et al., 1955). Isolation of the cystathionine-cleaving enzymes and their respective reaction prod...

The diet-tissue discrimination factor is the amount by which a consumer's tissue varies isotopically from its diet, and is therefore a key element in models that use stable isotopes to estimate diet composition. In this study we measured discrimination factors in blood (whole blood, red blood cells and plasma), liver, muscle and feathers of Double-crested Cormorants (Phalacrocorax auritus) for ...

The Mars Science Laboratory (MSL) Curiosity rover has been assessing the habitability and geologic history of Gale crater, since landing in 2012. One primary objectives mission was to investigate a clay-bearing unit identified using orbital spectral data, designated Glen Torridon (GT) region. This region particular interest because its elevated abundance clay minerals that may have preserved ge...

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. [1] Signatures of sulfur mass-independent fractionation (S-MIF) are observed for sulfur minerals in Archean rocks, ...

Enzymatic methyl transfer, catalyzed by catechol-O-methyltransferase (COMT), is investigated using binding isotope effects (BIEs), time-resolved fluorescence lifetimes, Stokes shifts, and extended graphics processing unit (GPU)-based quantum mechanics/molecular mechanics (QM/MM) approaches. The WT enzyme is compared with mutants at Tyr68, a conserved residue that is located behind the reactive ...

Green coffee bean isotopes have been used to trace the effects of different climatic and geological characteristics associated with the Hawaii islands. Isotope ratio mass spectrometry (IRMS) and inductively coupled plasma mass spectrometry ((MC)-ICP-SFMS and ICP-QMS) were applied to determine the isotopic composition of carbon (δ13C), nitrogen (δ15N), sulfur (δ34S), and oxygen (δ18O), the isoto...

Future missions to Venus will require a focused investigation of the atmospheric composition, to complete the story of its formation and evolution drafted by the probes of the 1970s and 1980s and developed further by recent missions such as Venus Express. Priority measurements include the mixing ratios and isotope ratios of all noble gases, detection of trace species in the lower atmosphere inc...