A sulfate-reducing bacterium using trinitrotoluene (TNT) as the sole nitrogen source was isolated with pyruvate and sulfate as the energy sources. The organism was able to reduce TNT to triaminotoluene (TAT) in growing cultures and cell suspensions and to further transform TAT to still unknown products. Pyruvate, H2, or carbon monoxide served as the electron donors for the reduction of TNT. The limiting step in TNT conversion to TAT was the reduction of 2,4-diamino-6-nitrotoluene (2,4-DANT) to triaminotoluene. The reduction proceeded via 2,4-diamino-6-hydroxylaminotoluene (DAHAT) as an intermediate. The intermediary formation of DAHAT was only observed in the presence of carbon monoxide or hydroxylamine, respectively. The reduction of DAHAT to triaminotoluene was inhibited by both CO and NH2OH. The inhibitors as well as DANT and DAHAT significantly inhibited sulfide formation from sulfite. The data were taken as evidence for the involvement of dissimilatory sulfite reductase in the reduction of DANT and/or DAHAT to triaminotoluene. Hydrogenase purified from Clostridium pasteurianum and carbon monoxide dehydrogenase partially purified from Clostridium thermoaceticum also catalyzed the reduction of DANT in the presence of methyl viologen or ferredoxin, however, as the main reduction product DAHAT rather than triaminotoluene was formed. The findings could explain the function of CO as an electron donor for the DANT reduction (to DAHAT) and the concomitant inhibitory effect of CO on triaminotoluene formation (from DAHAT) by the inhibition of sulfite reductase.(ABSTRACT TRUNCATED AT 250 WORDS)

D edicated to Professor A chim Trebst on the occasion o f his 60th birthdayCarbon Isotope Fractionation. Autotrophy. A cetyl-C oA Pathway, Reductive Citric Acid Cycle, Calvin Cycle Carbon isotope fractionation during autotrophic growth o f different bacteria which possess different autotrophic C 0 2 fixation pathways has been studied. 13C /l2C -R atios in the cell carbon of the follow ing bacteria were determined ( C 0 2 fixation pathway suggested or proven in paren theses): A lkaligenes eutrophus (reductive pentose phosphate cycle), D esulfobacterium autotrophicum and A cetobacterium w oodii (reductive acetyl-C oA pathway), D esulfobacter hydrogenophilus and T herm oproteus neutrophilus (reductive citric acid cycle). The A ö l3C values, which indicate the p e r m ille deviation o f the 13C content o f cell carbon from that o f the C O : used as the sole carbon source, range from -10%c (reductive citric acid cycle) over -26%c (reductive pentose phosphate cycle) to -36%c (reductive acetyl-C oA pathway). A cetate formed via the acetyl-C oA pathway by the acetogenic Acetobacterium w oodii showed a A 6 I3C = -40%c. These data are discussed in view of the different C 0 2 fixation reactions used by the bacteria and especially with regard to the isotopic com position of sedim entary carbon through time.

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The authors propose an on-chip microfluidic flow chemistry for non-covalent functionalization of single-walled carbon nanotubes (SWCNTs) as channel material in nanoelectronic carbon-nanotube field-effect transistors (CNT-FETs) specifically aiming for personalized optoplasmonic sensor solutions. Applying pyrene alkanethiol derivatives, dissolved in chloroform, and a dispersion of gold nanoparticles in triglyme, the authors conduct the proof-of-principle to fabricate arrays of photosensitive CNT-FETs using flow chemistry on wafercompatible hardware. The spectral photoresponse of the obtained sensor devices appears clear and reproducible and can be related to the surface plasmon polaritons of the gold nanoparticles. The sensor devices yield photometric responsivities of R A % 8 Â 10 À3 AW À1 and response times of t 0 % 9 s. The results extend a previously reported approach for covalent functionalization (Blaudeck et al., Microelectron. Eng. 2015, 137, 135) and show the potential of flow chemistry combined with wafer-level microfabrication for selectively functionalized nanostructured sensor arrays.

Biodegradation of 2,4,6-trinitrophenol (picric acid) byRhodococcus erythropolis HLPM-1 proceeds via initial hydrogenation of the aromatic ring system. Here we present evidence for the formation of a hydride-Meisenheimer complex (anionic ς-complex) of picric acid and its protonated form under physiological conditions. These complexes are key intermediates of denitration and productive microbial degradation of picric acid. For comparative spectroscopic identification of the hydride complex, it was necessary to synthesize this complex for the first time. Spectroscopic data revealed the initial addition of a hydride ion at position 3 of picric acid. This hydride complex readily picks up a proton at position 2, thus forming a reactive species for the elimination of nitrite. Cell extracts ofR. erythropolis HLPM-1 transform the chemically synthesized hydride complex into 2,4-dinitrophenol. Picric acid is used as the sole carbon, nitrogen, and energy source by R. erythropolisHLPM-1.