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Intercalation of the heteroaromatic π-donors tetraselenafulvalene (TSF) and tetramethyltetraselenafulvalene (TMTSF) into the layered host FeOCl results in new low-dimensional materials of stoichiometry FeOCl(TSF)1/8.5 and FeOCl(TMTSF)1/10. Powder x-ray diffracton data and FTIR spectra indicate that in each case the guest molecules are oriented perpendicular to the host layers and are present as the radical cations within the host galleries. Four-probe conductivity measurements show a 104 and 103-fold increase (for the TSF and TMTSF intercalates, respectively) in electrical conductivity over that of pristine FeOCl, although both FeOCl(TSF)1/8.5 and FeOCl(TMTSF)1/10 remain semiconductors.

Intercalation of TTF (tetrathiafulvalene), TTN (tetrathianaphthalene), and related organosulfur electron donors into Fe0C1 results in a significant expansion along the inter layer (b) axis, with the organosulfur molecules apparently inclined with respect to this axis. Electronic spectra suggest that the intercalates are semiconductors with band gaps of ca. 0.4 - 0.5 eV, consistent with previous conductivity data. Elastic neutron diffraction data (10K) show that magnetic ordering of the Fe0C1 host is abolished upon intercalation.

In a family study, levels of the C4 component of complement measured in 195 individuals show a continuous normal distribution. There is a slight but significant age effect, especially in females. Heritability is estimated at 62%. The effect of environment, however, remains substantial, and it is suggested that at some time during development the mechanism controlling the C4 levels establishes a general steady-state level whose effects remain after the divergence of sib environments with the approach of adulthood.

Five Tn5 mutants of Pseudomonas fluorescens AK-15 deficient in dissimilatory reduction of nitrite were isolated and characterized. Two insertions occurred inside the nitrite reductase structural gene (nirS) and resulted in no detectable nitrite reductase protein on a Western immunoblot. One mutant had Tn5 inserted inside nirC, the third gene in the same operon, and produced a defective nitrite reductase protein. Two other mutants had insertions outside of this nir operon and also produced defective proteins. All of the Nir- mutants characterized showed not only loss of nitrite reductase activity but also a significant decrease in nitric oxide reductase activity. When cells were incubated with 15NO in H2(18)O, about 25% of the oxygen found in nitrous oxide exchanged with H2O. The extent of exchange remained constant throughout the reaction, indicating the incorporation of 18O from H2(18)O reached equilibrium rapidly. In all nitrite reduction-deficient mutants, less than 4% of the 18O exchange was found, suggesting that the hydration and dehydration step was altered. These results indicate that the factors involved in dissimilatory reduction of nitrite influenced the subsequent NO reduction in this organism.

The mechanism of the denitrification and nitrosation reactions catalyzed by the heme cd-containing nitrite reductase from Pseudomonas stutzeri JM 300 has been studied with whole cell suspensions using H2(18)O, 15NO, and 15NO-2. The extent of H2(18)O exchange with the enzyme-bound nitrosyl intermediate, as determined by the 18O content of product N2O, decreased with increasing nitrite concentration, which is consistent with production of N2O by sequential reaction of two nitrite ions with the enzyme. Reaction of NO with whole cells in H2(18)O gave amounts of 18O in the N2O product consistent with equilibration of nitric oxide with a small pool of free nitrite. Using 15NO and NH2OH, competition between denitrification and nitrosation reactions was demonstrated, as is required if the enzyme-nitrosyl complex is an intermediate in both nitrosation and denitrification reactions. The first evidence for exchange of 18O between H2(18)O and a nitrosation intermediate occurring after the enzyme-nitrosyl complex, presumably an enzyme-bound nitrosamine, has been obtained. The collective results are most consistent with denitrification N2O originating via attack of NO-2 on a coordinated nitrosyl, as proposed earlier (Averill, B. A., and Tiedje, J. M. (1982) FEBS Lett. 138, 8-11).

We have obtained the iron K-edge extended X-ray adsorption fine structure spectra of the 3Fe ferredoxin II of Desulfovibrio gigas in the oxidized and reduced states. For both states, interpretation of the EXAFS data suggests that the Fe-S first shell coordination distance is near 2.25 A, in agreement with crystallographic studies of model compounds and proteins containing 2Fe-2S and 4Fe-4S centers, as well as with a recent crystallographic study of Azotobacter vinelandii ferredoxin I (Ghosh, D., Furey, W., Jr., O'Donnell, S., and Stout, C. D. (1981) J. Biol. Chem. 256, 4185-4192). The apparent Fe-Fe distance we obtain for the desulfovibrio protein (2.7 A) also agrees with similar distances seen in other Fe-S centers, except with the 3Fe cluster in the Azotobacter vinelandii ferredoxin I structure, for which an Fe-Fe distance of 4.2 A was reported. We conclude that either the two 3Fe ferredoxins have substantially different core dimensions, a possibility apparently unique to 3Fe centers among known Fe-S systems in proteins, or that one (or more) of the structural studies is in substantial error.

The time course of the precipitin reactions of concanavalin A with glycogen, dextran and ovalbumin was investigated by a light-scattering method near 30 degrees C in 10 mM-Tris/HCl buffer, pH 7.4, containing neutral salts, i.e. NaCl, KCl, NaBr, KI and NaClO4. With 0.8 microM-lectin and 0.36 mg of glycogen/ml, the half-life, t 1/2, of the precipitin reaction was independent of salt concentration between 0.1 M and 1.5 M, and was the same (175s) in the presence of NaCl, KCl, NaBr and KI but was significantly (27%) higher in NaClO4. In contrast, the five salts caused significant to marked enhancement in t 1/2 for the reactions of concanavalin A with dextran and ovalbumin. Likewise, whereas the turbidity produced in 1 h as a result of lectin-glycogen precipitation remained unchanged, those measured for the binding of dextran and ovalbumin were decreased in the presence of three salts. The increase in t 1/2 and decrease in turbidity were found to be higher with NaClO4, followed by KI; NaBr produced moderate and NaCl (or KCl) small but generally significant inhibition of the precipitin reactions with dextran and ovalbumin. The results showed that the lectin-ligand precipitin reactions involve salt-sensitive polar interactions that are less pronounced with compactly folded ligands such as glycogen.

Tn5 was used to generate mutants that were deficient in the dissimilatory reduction of nitrite for Pseudomonas sp. strain G-179, which contains a copper nitrite reductase. Three types of mutants were isolated. The first type showed a lack of growth on nitrate, nitrite, and nitrous oxide. The second type grew on nitrate and nitrous oxide but not on nitrite (Nir-). The two mutants of this type accumulated nitrite, showed no nitrite reductase activity, and had no detectable nitrite reductase protein bands in a Western blot (immunoblot). Tn5 insertions in these two mutants were clustered in the same region and were within the structural gene for nitrite reductase. The third type of mutant grew on nitrate but not on nitrite or nitrous oxide (N2O). The mutant of this type accumulated significant amounts of nitrite, NO, and N2O during anaerobic growth on nitrate and showed a slower growth rate than the wild type. Diethyldithiocarbamic acid, which inhibited nitrite reductase activity in the wild type, did not affect NO reductase activity, indicating that nitrite reductase did not participate in NO reduction. NO reductase activity in Nir- mutants was lower than that in the wild type when the strains were grown on nitrate but was the same as that in the wild type when the strains were grown on nitrous oxide. These results suggest that the reduction of NO and N2O was carried out by two distinct processes and that mutations affecting nitrite reduction resulted in reduced NO reductase activity following anaerobic growth with nitrate.

The purple acid phosphatase from beef spleen, which contains two iron atoms per molecule, is EPR silent in its native (oxidized) purple form. Treatment with mild reducing agents results in conversion to a pink, enzymatically active form, which exhibits an unusual EPR signal centered at g approximately equal to 1.77; double integration of the EPR spectrum gives one spin per two iron atoms. A similar EPR spectrum is observed for enzyme reduced anaerobically by one electron, using sodium dithionite. Variable-temperature magnetic susceptibility measurements show that the oxidized and reduced proteins are both antiferromagnetically coupled systems, with S = 0 and 1/2 ground states, respectively. Replacement of one of the iron atoms by zinc produces an FeZn enzyme with full catalytic activity. The FeZn enzyme exhibits a highly temperature dependent g = 4.3 EPR signal, and magnetic susceptibility data are consistent with an S = 5/2 paramagnet. Treatment of the FeZn enzyme with phosphate, a competitive inhibitor, results in sharpening of the EPR spectrum; double integration at 77 K gives one spin per iron. These results strongly suggest the presence of a spin-coupled bimetallic unit at the active site of the enzyme.

The compound (Et4N)2[Fe4S4(SCH2Ph)4] has been prepared and its structure determined by x-ray diffraction. The Fe4S4core of the anion possesses a configuration of D2dsymmetry that is closely related to the Fe4S4active-site structures of the high-potential iron protein from Chromatiumand the ferredoxin from Micrococcus aerogenes. Electronic properties of the tetrameric anion have been partially characterized by measurement of proton magnetic resonance, Mössbauer, photoelectron, and electronic spectra, and magnetic susceptibility. Comparison of corresponding properties of [Fe4S4(SCH2Ph)4]2-and the proteins implies that the oxidation levels of the synthetic tetramer, the reduced form of the high-potential protein, and the oxidized form of the 8-Fe ferredoxins are equivalent. The tetramer possesses the one-electron redox capacity associated with the 4-Fe centers of the ferredoxins. The structural and collective electronic features of [Fe4S4(SCH2Ph)4]2-reveal it to be the first well-defined synthetic analogue of the active site of an iron-sulfur protein.

BackgroundWestern Australia (WA) passed legislation supporting formal advance care planning (ACP) in 2010, allowing Advance Health Directive (AHD) and Enduring Power of Guardianship (EPG) forms. It is timely to audit the quality of end-of-life care provided in a rural area.AimReport ACP uptake and impact on end-of-life care in a rural hospital setting.MethodsThis retrospective case notes-based audit of 90 admissions resulting in death was conducted in five rural hospitals in the Great Southern region of WA in 2012: the 100-bed regional centre (N=50) and four more remote ∼10-bed facilities (N=10). A palliative care nurse used an in-house designed audit tool to collect data on demographics, process and outcomes measures. A palliative physician double coded five randomly selected sets of notes.ResultsMost patients elderly (M=79.6 years), admitted via ED (58%), on average 13 days before death. Malignancy accounted for 40% of deaths. Some form of ACP was documented in 34%, with 9% having an AHD and 1% having an EPG. 50% died on the Liverpool end-of-life care pathway, those on the pathway scored higher on a composite measure of care quality (χ2(2,90)=31.6, p<0.001). ACP documentation did not predict likelihood of being commenced on the pathway (p>0.05) or scores on the composite measure (p>0.05).DiscussionAs ACP is promoted in our community, our rural hospital network must develop system-wide responses to guarantee ACP influences care.ConclusionThis audit reports baseline data, which can be repeated following ACP-based interventions.

New intercalation compounds of the organic electron donors (I)‐(III) with the host FeOCl are prepared by direct reaction of solutions of the tetrathiolene molecules with solid FeOCl.

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The reaction sequence shown in the scheme yields the new title clusters.

The reactions of (I) with stoichiometric amounts of the lithium salt of the thiols (II) give the dimerization product (III).

Starting with o‐dinitrobenzene (I), the flavin derivative (V) is obtained by base‐catalyzed coupling of (I) with the amine (II) followed by catalytic hydrogenation and cyclocondensation with alloxan (IV).

, Li2Mo6Se6(I), dissolved in propylene carbonate.

Starting with the anthraquinone (IIa), the 1,8‐disubstituted anthracenes (Ia) ‐ (Ic) are prepared.

Neutron diffraction studies on powder samples of the title compounds establish that tetrathiafulvalene (TTF) intercalated into FeOCl (space group Pmnm) contributes to the diffraction pattern and exhibits long‐range order.