Frankia sp., the actinomycetous endophyte in nitrogen-fixing actinorhizal nodules, may differentiate two forms from its hyphae: vesicles and sporangia. In root nodules of Comptonia peregrina (L.) Coult. and Myrica gale L., sporangia may be either absent or present. Nitrogenase activity and symbiotic efficiency were contrasted in spore(+) and spore(-) nodules of these two host genera. Seedlings ...

Nitrogen fixation associated with sugarcane was monitored ushg acetylene reducti,on tests and bacteriological techniques. Soil cores and trash from cane fields showed acetylene reducing activity. This activity was usually low in association with sandy soils. Where high activity was detected in soil cores it correlat~d with the wet weight of roots in each core. Nitrogen-fixing bacteria resemblin...

Heterotelechelic polystyrene (PS), poly(tert-butyl acrylate) (PtBA), and poly (methyl acrylate) (PMA), containing both azide and triisopropylsilyl (TIPS) protected acetylene end groups, were prepared in good control (Mw/Mn 1.24) by atom transfer radical polymerization (ATRP). The end groups were independently applied in two successive ‘‘click’’ reactions, that is: first the azide termini were f...

The ammonia monooxygenase (AMO) of Nitrosomonas europaea is a metalloenzyme that catalyses the oxidation of ammonia to hydroxylamine. We have identified histidine 191 of AmoA as the binding site for the oxidized mechanism-based inactivator acetylene. Binding of acetylene changed the molecular mass of His-191 from 155.15 to 197.2 Da (+42.05), providing evidence that acetylene was oxidized to ket...

We have investigated, by means of ab initio and DFT calculations, the magnitude of through-space spin-spin couplings (JCH and JHH) in CH/π bonded van der Waals dimers involving acetylene, and in a structurally related covalent compound (4ethynylphenanthrene). Within regions where the interaction is stabilizing JHH couplings are very small (< 0.1 Hz) for all complexes. In the acetylene-methane c...

Acetylene-black paste without a light scattering layer was applied to meso-porous TiO2 photo-electrode films with a crystalline framework, a low residual carbon, and a tunable morphological pore size. The thermal-treated TiO2 photo-electrode films had an increased acetylene-black concentration with an increase in artificial pores and a decrease in residual carbon. The performance of dye-sensiti...