Abstract  PESTAB Therapy of chronic poisonings with organochlorine compounds, such as DDT, BHC, 2-KF, dichloralurea, 2,4-D, polychloropinene, and hexachlorobutadiene, is reviewed. Since the mechanism of action of organochlorine compounds in humans is not known, specific antidote therapy is not available. Glucose, calcium gluconate, and vitamins, especially vitamin B, are useful during the initial stage of the chronic poisoning, characterized by autonomic dystonia and the asthenic syndrome. Belladonna preparations are used for elimination of autonomic irritability and of vasculay spasms, and tranquilizers are given to reduce emotional lability. Vitamin preparations, cocarboxylase, adenosine triphosphatase, and oxygen therapy are used to control hypoxia and to increase tonus. Electrophoresis according to Shcherbak with calcium chloride, vitamin B1, dimedrol, or novocaine is also useful. Vitamin B12 is given to control toxic polyneuritis. Hemorrhagic vasculitis is treated with vitamins C and P. B vitamins, thiamine, riboflavin, glucose, and insulin are used for the therapy of toxic hepatitis. Impairments of gastric secretory function are corrected by specific diets, nicotinic acid, and pyridoxine. Vitamins C and B, thiamine, folic acid, and iron preparations are useful in anemia.

Abstract  A new application of capillary electrophoresis (CE) for measuring inorganic anions in hailstones was carried out. Five hailstone specimens were collected from large blocks of ice that fell in January 2000 in some provinces of Spain. Sample handling and preparation procedures were performed with care. CE analysis of anions was carried out using indirect UV detection at 254 nm with a negative power supply (-15 kV) and hydrostatic injection (10 cm for 30 s) at 35 degrees C. Anion separation was completed in less than 4 min. The working electrolyte consisted of 4.7 mM sodium chromate, 4.0 mM OFM-OH (tetradecyltrimethylammonium hydroxide), 10 mM CHES [2-(N-cyclohexylamino)ethanesulfonic acid], and 0.1 mM calcium gluconate (pH 9.1). Good repeatability of migration times after eight injections (<0.7% RSD), adequate linearity responses (r2>0.9) as well as satisfactory detection limits (<0.35 ppm) were achieved. The analytical results provided by CE were compared with those obtained by traditional wet-chemical (WCH) methods. Most of the results obtained by CE were consistent with those of WCH, except for one sample.

Abstract  Lactobionic acid, [4-beta-(galactosido)-D-gluconic acid] = LBA, is the major component of the Wisconsin organ transplantation preservant fluid and may suppress oxygen radical-induced tissue damage upon reperfusion by the control of FeII autoxidation. FeII and FeIII complexes of LBA and the related gluconic acid (GLC) have been studied herein by titrimetric, infrared, and electrochemical methods (CV; DPP). FeII(GLC) forms quickly at pH 7, but FeII(LBA) reacts in two steps, the second requiring 4 hr. The initial complex lacks coordination of the LBA carboxylate (C-1) and is bound by the "2,3,5" hydroxyl groups. The slow rearrangement forms a "1,2,3,6" chelate which FeII(LBA) shares in common with the donor set of the FeIII(LBA) complex. Titration data shows the removal of three protons from LBA through pH 5 and an additional proton from pH 6 to 9 which is indicative of the [FeIII(LBA)(OH)(H2O)]- formulation with LBA donating at the "1,2,3,6" positions. The more stable, second form of FeII(LBA) has been investigated in its oxidation mechanisms with H2O2 and O2 using selected trapping agents for HO. and ferryl intermediates. Eighty-six percent of the oxidation events of FeII(LBA)/H2O2 occurs in steps involving formation and reduction of freely diffusible HO.. These pathways are altered by the known HO. traps t-butanol, dmso, ethanol, and methanol in the manner predictable for beta-oxidizing radicals (from t-butanol or dmso) and alpha-reducing radicals (from ethanol and methanol). Fourteen percent of the FeII(LBA)/H2O2 reaction occurs via FeIVO intermediates not trapped by t-butanol or dmso, but intercepted by primary and secondary alcohols. The HO. generating pathways are responsible for a competitive LBA ligand oxidation at the C-2 position via HO., formed from FeII(LBA) and H2O2 within the original reaction cage. Competitive ligand oxidation at C-2 is absent for the FeII(LBA)/O2 autoxidation, indicative of a different redox mechanism. The FeII(LBA)/O2 reaction rate is first-order in each component and is insensitive to the presence of t-butanol as an HO. trap. These observations support a ferryl intermediate in the autoxidation pathway and the absence of HO. or free H2O2 during autoxidation. Although chelation of FeII by hard ligand donors such as edta4-, Cl-, or HPO4(2-) accelerate the rate of autoxidation of FeII, chelation of carboxylate, alkoxy, and hydroxyl donors of LBA does not accelerate autoxidation. The implications of these findings, and the absence of an inner-sphere coordination role of the 4-beta-(galactosido) functionality toward the action of LBA in organ preservant fluids, are discussed.

Abstract  About twenty years ago, the cofactor pyrroloquinoline quinone, PQQ, was discovered. Here the author gives his personal view on the reasons why this cofactor was so lately discovered and how the steps in its identification were made. The discovery not only led to subsequent studies on the physiological significance of PQQ but also initiated investigations on other enzymes where the presence of PQQ was expected, resulting in the discovery of three other quinone cofactors, TPQ, TTQ, and LTQ, which differ from PQQ as they are part of the protein chain of the enzyme to which they belong. Enzymes using quinone cofactors, the so-called quinoproteins, copper-quinoproteins, and quinohemoproteins, are mainly involved in the direct oxidation of alcohols, sugars, and amines. Some of the PQQ-containing ones participate in incomplete bacterial oxidation processes like the conversion of ethanol into vinegar and of D-glucose into (5-keto)gluconic acid. Soluble glucose dehydrogenase is the sensor in diagnostic test strips used for glucose determination in blood samples of diabetic patients. Quinohemoprotein alcohol dehydrogenases have an enantiospecificity suited for the kinetic resolution of racemic alcohols to their enantiomerically pure form, certain enantiomers being interesting candidates as building block for synthesis of high-value-added chemicals. Making up for balance after twenty years of quinoprotein research, the following conclusions can be drawn: since quinoproteins do not catalyze unique reactions, we know now that there are more enzymes which catalyze one and the same reaction than we did before, but do not understand the reason for this (compare e.g. NAD/NADP-dependent glucose dehydrogenases, flavoprotein glucose oxidase/dehydrogenase, and soluble/membrane-bound, PQQ-containing glucose dehydrogenases, enzymes all catalyzing the oxidation of beta-D-glucose to delta-gluconolactone but being quite different from each other); however, taking a pragmatic point of view, the foregoing can also be regarded as a positive development since as illustrated by the examples given above, the enlargement of the catalytic arsenal with quinoprotein enzymes provides in more possibilities for enzyme applications; the hopes that PQQ could be a new vitamin have diminished strongly after it has become clear that its occurrance is restricted to bacteria; the impact factor is broader than just the development of the field of quinoproteins, since together with that of enzymes containing a one-electron oxidized amino acid residue as cofactor, it has emphasized that cofactors not only derive from nucleotides (e.g. FAD, NAD) but also from amino acids. Finally, strong indications exist to assume that this is not the end of the story since other quinone cofactors seem awaiting their discovery.

Abstract  1. Although calcium gluconate (CG) is recommended in the treatment of hydrofluoric acid (HF) eye burn its efficacy seems to be controversial, and controlled human or animal studies are limited. The study's objective is to compare the efficacy of 1% CG and normal saline irrigation for the treatment of HF eye injury in animals. 2. 0.05 ml 2% HF was instilled to anesthetized rabbit's eyes. One minute later, four treatment groups were studies: (1) irrigation with normal saline followed by topical antibiotics, corticosteroids and cycloplegics for 48 h (n = 10); (2) irrigation with 1% CG followed by the same topical treatment (n = 9); (3) as group 1 and 1% CG drops over 48 h (n = 10); (4) as group 3, and injection of 1% CG subconjunctivally after irrigation (n = 9). 3. Corneal erosion area, corneal haziness, conjunctival status, vascularization (pannus) and acidity were assessed before injury, immediately after initial treatment and 1, 2, 7 and 14 days thereafter by slit lamp aided by fluorescein staining. 4. Conjunctival pH dropped from 6.0-6.5 to 2.5-3 after injury and increased to 6-6.5 after irrigation. Corneal erosion: smaller in groups 2, 3, significantly so at 2 days, but not different at 14 days. Corneal haziness: more severe in group 4, at 14 days, insignificant. Conjunctival damage: significantly worse in group 4 at 2, 7 and 14 days. Pannus appeared in 2-4 eyes in each group. 5. It seems that for HF injury 1% CG did not have any significant advantage over saline irrigation and topical treatment only. It might have some initial and temporary effect on healing process especially that involving erosion. Given subconjunctivally, 1% CG may be toxic and worsens clinical outcome.

Abstract  In glucose minimal medium a PTS- strain of Escherichia coli [delta (ptsH ptsI crr)] could grow slowly (doubling time, d = 10 h). When the population reached 5 x 10(6) to 2 x 10(7) cells ml-1, mutants growing rapidly (d = 1.5 h) appeared and rapidly outgrew the initial population. These mutants (EF mutants) do not use a constitutive galactose permease for glucose translocation. They synthesize sufficient pyrroloquinoline quinone (PQQ) to yield a specific activity of glucose dehydrogenase (GDH) equivalent to that found in the parent strain grown in glucose minimal medium supplemented with 1 nM-PQQ. Membrane preparations containing an active GDH oxidized glucose to gluconic acid, which was also present in the culture supernatant of EF strains in glucose minimal medium. Glucose utilization is the only phenotypic trait distinguishing EF mutants from the parent strain. Glucose utilization by EF mutants was strictly aerobic as expected from a PQQ-dependent catabolism. The regulation of PQQ production by E. coli is discussed.

Abstract  We assessed mechanisms of acetylcholine- and bradykinin-induced relaxations in human omental resistance vessels. Ring segments (approximately 200 microns normalized ID) were dissected from omental biopsies obtained from women at laparotomy (nonpregnant) or at cesarean delivery (pregnant) and were studied under isometric conditions in a Mulvany-Halpern myograph. All arginine vasopressin-preconstricted vessels relaxed in a strictly endothelium-dependent manner to acetylcholine and bradykinin; maximal relaxations were not decreased by either NG-nitro-L-arginine or indomethacin. By contrast, bradykinin failed to relax vessels that had been preconstricted with potassium gluconate. In the combined presence of NG-nitro-L-arginine and indomethacin, addition of charybdotoxin, a selective antagonist of some calcium-sensitive potassium channels, did not inhibit maximal bradykinin-induced relaxation. By contrast, addition of 10 mmol/L tetraethylammonium chloride abolished relaxation in vessels from nonpregnant women but not in vessels from gravidas. We conclude that bradykinin relaxes these human resistance arteries in an endothelium-dependent but predominantly nitric oxide- and prostanoid-independent manner; relaxation likely depends on the action of an endothelium-derived hyperpolarizing vasodilator. Furthermore, in striking contrast to mechanistic insights from animal studies, human pregnancy appears to augment a mechanism of endothelium-dependent relaxation in these vessels that is insensitive to the inhibitors noted above. Whether a similar novel vasodilator mechanism in vivo contributes to the physiological vasodilation that characterizes human gestation or whether failure of such a mechanism might lead to preeclampsia remains the subject of future study.

Abstract  Membrane-integrated quinoprotein glucose dehydrogenase from Acinetobacter calcoaceticus was produced by heterologous expression of the gene for it in an Escherichia coli recombinant strain. The apoenzyme (lacking the cofactor pyrroloquinoline quinone, PQQ) was solubilized with Triton X-100 and purified to homogeneity. Reconstitution of the apoenzyme to full activity in the assay was achieved with a stoichiometric amount of PQQ in the presence of Mg2+. Just as for other PQQ-containing dehydrogenases where Ca2+ fulfills this role, Mg2+ anchors PQQ to the mGDH protein and activates the bound cofactor. This occurs in a precise way since high anomer specificity was found for the enzyme toward the sugars tested. Although the steady-state-type kinetics were as expected for a dye-linked dehydrogenase (ping-pong) and the PQQ in it was present in oxidized form, addition of glucose to the holoenzyme resulted in a very slow but continuous production of gluconolactone; i.e., the reaction did not stop after one turnover, with O2 apparently acting as an (albeit poor) electron acceptor by reoxidizing PQQH2 in the enzyme. The surprisingly low reactivity with glucose, in the absence of dye, as compared to the activity observed in the steady-state assay appeared to be due to formation of an anomalous enzyme form, mGDH. Formation of normal holoenzyme, mGDH, reducing added glucose immediately to gluconolactone (in one turnover), was achieved by treating mGDH with sulfite, by reconstituting apoenzyme with PQQ in the presence of sulfite, or by applying assay conditions to mGDH (addition of PMS/DCPIP). As compared to other quinoprotein dehydrogenases, mGDH appears to be unique with respect to the mode of PQQ-binding, as expressed by the special conditions for reconstitution and the absorption spectra of the bound cofactor, and the reactivity of the reduced enzyme toward O2. The primary cause for this seems not to be related to a different preference for the activating bivalent metal ion but to the special way of binding of PQQ to mGDH.

Abstract  The production of citric and gluconic acids from fig by Aspergillus niger ATCC 10577 in solid-state fermentation was investigated. The maximal citric and gluconic acids concentration (64 and 490 g/kg dry figs, respectively), citric acid yield (8%), and gluconic acid yield (63%) were obtained at a moisture level of 75%, initial pH 7.0, temperature 30 degrees C, and fermentation time in 15 days. However, the highest biomass dry weight (40 g/kg wet substrate) and sugar utilization (90%) were obtained in cultures grown at 35 degrees C. The addition of 6% (w/w) methanol into substrate increased the concentration of citric and gluconic acid from 64 and 490 to 96 and 685 g/kg dry fig, respectively.

Abstract  A new family of activated glycosidic compounds has been designed and synthesized: (2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-2-nitrophenylmethane (1). It is stable in conditions commonly used for synthesis, and it can be converted to a sugar lactone derivative merely by photoirradiation (λ=365 nm): 2,3,4,6-tetra-O-acetyl-D-glucono-1,5-lactone (2). A mechanism for the reaction is proposed. The photochemical conversion of 1 in the presence of methanol has also been demonstrated, giving rise to methyl 2,3,4,6-tetra-O-acetyl-D-gluconate (3).

Abstract  Butyrate has an antitumorigenic effect on colorectal cancer cell lines. Dietary sodium gluconate (GNA) promotes butyrate production in the large intestine. Accordingly, we examined the effect of dietary GNA on tumorigenesis in the large intestine in rats. Male Fisher-344 rats (n = 32) were divided into 4 groups: 2 diets (with or without 50 g GNA/kg basal diet) X 2 treatments (with or without carcinogen administration). Colonic tumors were induced by 3 intraperitoneal injections of azoxymethane (115 mg/kg body wt, 1 time/wk) and dietary deoxycholic acid (2 g/kg basal diet). The experiment was conducted for 33 wk except for a few rats. Ingestion of GNA increased cecal butyrate concentration at the end of experiment (P < 0.01). No tumor development occurred in the untreated groups. Ingestion of GNA decreased the incidence of tumors in rats administered the carcinogen (37.5 vs. 100%, P < 0.05). Ingestion of GNA also decreased the mean number of tumors per rat (0.5 +/- 0.8 vs. 2.8 +/- 1.5, P < 0.01). beta-Catenin accumulation and TdT-mediated dUTP nick end labeling (TUNEL) positive cells in tumors were histochemically examined. The results of this study suggested that the antitumorigenic effect of GNA may involve the stimulation of apoptosis through enhanced butyrate production in the large intestine.

Abstract  The mineral phosphate-solubilizing (MPS) activity of a Pantoea agglomerans strain, namely MMB051, isolated from an iron-rich, acidic soil near Ciudad Piar (Bolívar State, Venezuela), was characterized on a chemically defined medium (NBRIP). Various insoluble inorganic phosphates, including tri-calcium phosphate [Ca(3)(PO(4))(2)], iron phosphate (FePO(4)), aluminum phosphate (AlPO(4)), and Rock Phosphate (RP) were tested as sole sources of P for bacterial growth. Solubilization of Ca(3)(PO(4))(2) was very efficient and depended on acidification of the external milieu when MMB051 cells were grown in the presence of glucose. This was also the case when RP was used as the sole P source. On the other hand, the solubilization efficiency toward more insoluble mineral phosphates (FePO(4) and AlPO(4)) was shown to be very low. Even though gluconic acid (GA) was detected on culture supernatants of strain MMB051, a consequence of the direct oxidation pathway of glucose, inorganic-P solubilization seemed also to be related to other processes dependent on active cell growth. Among these, proton release by ammonium (NH(4)(+) ) fixation appeared to be of paramount importance to explain inorganic-P solubilization mediated by strain MMB051. On the contrary, the presence of nitrate (NO(3)(-) ) salts as the sole N source affected negatively the ability of MMB051 cells to solubilize inorganic P.

Abstract  The Na(+)/H(+) exchanger has been the only unequivocally demonstrated H(+)-transport mechanism in the synaptosomal preparation. We had previously suggested that a Cl(-)-H(+) symporter (in its acidifying mode) is involved in cytosolic pH regulation in the synaptosomal preparation. Supporting this suggestion, we now show that: (1) when synaptosomes are transferred from PSS to either gluconate or sulfate solutions, the Fura-2 ratio remains stable instead of increasing as it does in 50 mM K solution. This indicates that these anions do not promote a plasma membrane depolarization. (2) Based in the recovery rate from the cytosolic alkalinization, the anionic selectivity of the Cl(-)-H(+) symporter is NO(3)(-) > Br(-) > Cl(-) > I(-) = isethionate = sulfate = methanesulfonate = gluconate. (3) PCMB 10 muM inhibits the gluconate-dependent alkalinization by 30 +/- 6%. (4) Neither Niflumic acid, 9AC, Bumetanide nor CCCP inhibits the recovery from the cytosolic alkalinization.

Abstract  Ion channels from the midgut apical membrane of gypsy moth (Lymantria dispar) larvae were studied following mechanical fusion of brush-border membrane vesicles with planar phospholipid bilayer membranes. In symmetrical 300 mmol l(-)(1) KCl (pH 9.0), nine different channels with conductances ranging from 27 to 795 pS and linear current/voltage relationships were resolved. In the presence of a KCl gradient across the bilayer (450 mmol l(-)(1 )cis/150 mmol l(-)(1 )trans), 11 different conductance levels ranging from 16 to 850 pS were detected. The channels were slightly cationic: the zero-current reversal potential was shifted by -5 mV to -21 mV compared with symmetrical KCl conditions, corresponding to p(K)/p(Cl) permeability ratios of 1.5-8.0. Most channels were neither voltage-dependent nor Ca(2+)-sensitive and displayed complex gating kinetics. Addition of Ba(2+) or Cs(+) to both sides of the bilayer had little effect on channel activity, but fewer distinct channels were observed when KCl was replaced by potassium gluconate, suggesting an effect of Cl(-) on channel activity. A reduced number of channels was also detected when KCl was replaced by N-methyl- d-glucamine-HCl. Under asymmetrical N-methyl-d-glucamine-HCl conditions, only anionic channels were observed. They exhibited current rectification (35 pS at negative voltages and 81 pS at positive voltages) and were strongly voltage-dependent.

Abstract  Nanostructured carbon xerogels with controlled pore texture are used as catalyst support for the oxidation in aqueous phase of D-glucose into D-gluconic acid on Pd-Bi/C catalysts. X-ray photoelectron spectroscopy shows that metal active sites are not homogeneously dispersed in the spherical support particle but are concentrated in an external spherical layer. The influence of mass transfers on reaction kinetics is highlighted. Internal diffusional limitations are quantified using the Weisz modulus. It is shown that measuring the true kinetic reaction rate implies to choose the experimental conditions within a small range of values. (C) 2010 Elsevier B.V. All rights reserved.

Abstract  Biomasses of methylotrophic bacteria, yielded by biotechnological processes as waste products, can represent a source of ubiquinones, especially of the ubiquinone-10. Possibilities for the separation of ubiquinones were studied on waste biomasses from the microbial production of gluconic acid, from the production of intracellular poly-beta-hydroxybutyric acid (PHB) and from the sewage treatment. The ubiquinones are extracted with supercritical CO2 in the presence of methanol or ethanol as entrainer. The separation of ubiquinones with supercritical extraction was more effective than with conventional extraction methods. The advantages are especially the low extract quantities and the high ubiquinone content in the extracts. The crude ubiquinones can be purified by using the preparative HPLC technique.

Abstract  75As NMR (Nuclear Magnetic Resonance) was used as a probe of arsenate interactions in solution. The linewidth at half-height of the 75As NMR signal of arsenate was studied as a function of solution pH and temperature. Below pH 11.5, the 75As signal was too broad to be detected, but at higher pH, up to pH = 13.5, the signal became much narrower. This indicates that the arsenate species AsO4(3-) is quite symmetric, but the asymmetry of HAsO4(2-) is sufficient to cause extensive quadrupolar relaxation of the 75As nucleus. A full pH range 75As and proton NMR study of the interaction of arsenate with ethanol, ethylene glycol, glycerol, ribose, mannose, glucose, gluconic acid and acetate was undertaken in order to follow arsenate ester formation. The 75As line broadening effects and the proton ligand shifts observed indicate that complexation of arsenate by ribose, mannose, glucose, ethanol, ethylene glycol, and glycerol occurs at pH 12.7. However, no significant interaction is detected by NMR with gluconic acid or acetate. The effect of the nucleoside adenosine is quite small and those of phosphate and of the nucleotides AMP and ADP are negligible. The interaction of arsenate with potential cationic centers, such as the basic amino acids lysine and arginine and some macrocyclic triamines, was also studied. Such interaction depends on the pKa for protonation of the amine groups.

Abstract  Hazmat emergency preparedness is critical, especially as Hong Kong prepares for major international events, such as the 2008 Olympic Equestrian Games. No published medical study has described the identities and quantities of dangerous goods (DG) in the Kowloon area and listed what antidotes are needed for these DG. This study describes what hazardous materials are most common in Kowloon to prioritise emergency preparedness and training. Materials & methods: Design: A descriptive, cross-sectional study. Setting: The Hong Kong Special Administrative Region, specifically Kowloon. Sample: The Hong Kong Fire Services Department (HKFSD) Dangerous Goods Database (DGD). Interventions: Descriptive statistical analyses with Stata 9.2. Chiefoutcome: Identifying and quantifying dangerous goods in the HKFSD DGD. Results: Most DG do not have antidotes. The most common DG with recognised antidotes are carbon monoxide, methylene chloride, fluorine, fluorides, fluoroboric acid, cyanides, nitriles, methanol, nitrobenzene, nitrites, and nitrates. The most common categories of DG are substances giving off inflammable vapours, compressed gases, and corrosive and poisonous substances. Conclusions: Hazmat emergency preparedness and training should emphasize these most common categories of DG. Disaster planning should ensure adequate antidotes for DG with recognised antidotes, i.e., oxygen for carbon monoxide and methylene chloride; calcium gluconate or calcium chloride for fluorine, fluorides, and fluoroboric acid; hydroxocobalamin for cyanides and nitriles; ethanol for methanol; and methylene blue for methaemoglobinaemia produced by nitrobenzene, nitrites, and nitrates. Supportive care is essential for patients exposed to hazardous materials because most dangerous goods do not have antidotes.

Abstract  This study used batch reactors to characterize the mechanisms and rates of elemental release (Al, Ca, K, Mg, Na, F, Fe, P, Sr, and Si) during interaction of a single bacterial species (Burkholderia fungorum) with granite at T = 28 degrees C for 35 days. The objective was to evaluate how actively metabolizing heterotrophic bacteria might influence granite weathering on the continents. We supplied glucose as a C source, either NH4 or NO3 as N sources, and either dissolved PO4 or trace apatite in granite as P sources. Cell growth occurred under all experimental conditions. However, solution pH decreased from similar to 7 to 4 in NH4-bearing reactors, whereas pH remained near-neutral in NO3-bearing reactors. Measurements of dissolved CO2 and gluconate together with mass-balances for cell growth suggest that pH lowering in NH4-bearing reactors resulted from gluconic acid release and H+ extrusion during NH4 uptake. In NO3-bearing reactors, B. fungormum likely produced gluconic acid and consumed H+ simultaneously during NO3 utilization. Over the entire 35-day period, NH4-bearing biotic reactors yielded the highest release rates for all elements considered. However, chemical analyses of biomass show that bacteria scavenged Na, P, and Sr during growth. Abiotic control reactors followed different reaction paths and experienced much lower elemental release rates compared to biotic reactors. Because release rates inversely correlate with pH, we conclude that proton-promoted dissolution was the dominant reaction mechanism. Solute speciation modeling indicates that formation of Al-F and Fe-F complexes in biotic reactors may have enhanced mineral solubilities and release rates by lowering Al and Fe activities. Mass-balances further reveal that Ca-bearing trace phases (calcite, fluorite, and fluorapatite) provided most of the dissolved Ca, whereas more abundant phases (plagioclase) contributed negligible amounts. Our findings imply that during the incipient stages of granite weathering, heterotrophic bacteria utilizing glucose and NH4 only moderately elevate silicate weathering reactions that consume atmospheric CO2. However, by enhancing the dissolution of non-silicate, Ca-bearing trace minerals, they could contribute to high Ca/Na ratios commonly observed in granitic watersheds. (c) 2007 Elsevier Ltd. All rights reserved.

Abstract  It is still a challenge to link specific metabolic activities to certain species in a microbial community because of methodological limitations. We developed a method to analyze the specific metabolic activity of a single bacterial species within a consortium making use of [(13)C(7)]-toluene for metabolic labelling of proteins. Labelled proteins were subsequently analyzed by 2D gel electrophoresis (2-DE) and mass spectrometry (MS) to characterize their identity as well as their (13)C content as an indicator for function and activity of the host organism. To establish this method, we analyzed the metabolic incorporation of (13)C carbon atoms into proteins of Aromatoleum aromaticum strain EbN1. This strain is capable of metabolizing toluene under nitrate-reducing conditions and was grown in either pure culture or in a mixed consortium with a gluconate-consuming enrichment culture. First, strain EbN1 was grown with non-labelled toluene or labelled [(13)C(7)]-toluene as carbon sources, respectively, and their proteins were subjected to 2-DE. In total, 60 unique proteins were identified by MALDI-MS/MS. From 38 proteins, the levels of (13)C incorporation were determined as 92.3+/-0.8%. Subsequently, we mixed strain EbN1 and the enrichment culture UFZ-1, which does not grow on toluene but on gluconate, and added non-labelled toluene, [(13)C(7)]-toluene and/or non-labelled gluconate as carbon sources. The isotope labelling of proteins was analyzed after 2-DE by MS as a quantitative indicator for metabolic transformation of isotopic-labelled toluene by the active species of the consortium. Incorporation of (13)C was exclusively found in proteins from strain EbN1 at a content of 82.6+/-2.3%, as an average calculated from 19 proteins, demonstrating the suitability of the method used to identify metabolic active species with specific properties within a mixed culture.

Abstract  We report a 27-week, 850 g infant with severe Streptococcus group B sepsis and life-threatening hyperkalemia due to progressive anuria. On the fourth day of life, after he failed treatment with diuretics, salbutamol, insulin, calcium gluconate and sodium bicarbonate, he was treated with sorbitol-free Kayexalate enemas. Potassium level slowly decreased from 9.2 mmol/l to normal level along with a recovery of normal urine output. On the 11th day of life, clinical and radiological signs of a perforated necrotizing enterocolitis (NEC) occurred and the patient required surgical intestinal resection. Histologic examination of the ileum specimen revealed areas of necrosis with fibrosis and giant cell reaction to a nonpolarizable material consistent with sodium polystyrene sulfonate. Usually, Kayexalate is suspended in hyperosmolar sorbitol solutions and the elevated osmolarity seems to be responsible for hemorrhagic colitis, transmural necrosis and definitely NEC. Our case report shows that Kayexalate per se, and not necessarily suspended in sorbitol, can lead to gastrointestinal tract complications and NEC in preterm infants.

Abstract  Mechanistic investigation of the oxidative degradation of d-fructose (D-Fruc) has been studied by spectrophotometric technique. Molecular mechanics (MM +) calculations suggest that the potential energy (PE/kcal mol-1) of the d-fruc (opening structure) is at least three (3.71) times more stable than the PE of the cycling structure of the same matrix. The oxidation constant (Kox) of the anionic form of the d-Fruc (Fruc-NaOH) is about seven times greater than that of the protonated form (Fruc-H2SO4). Therefore, the anionic form is more highly oxidizable than is the cationic form of this matrix. The limit of detection can be as low as 18 ppm (mg L-1) of d-Fruc. This is about 60 times lower than the blood sugar level (BSL) or 100 times lower than that reported previously. The proposed procedure was applied successfully for the oxidation of D-Fruc in uni-fructose powder. The anionic form of D-Fruc (Fruc-NaOH) has the ability to store energy about 744.72 kJ g-1 h at 608 nm in a condensed lightweight form. Kinetic parameters of the oxidative degradation of the anionic form of D-Fruc at different concentration were deduced. A number of models were used to evaluate the kinetic parameters. The mechanism of the degradation of D-Fruc is explained on the basis of kinetic parameters. [ABSTRACT FROM AUTHOR] Copyright of Spectroscopy Letters is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts)

Abstract  The use of solid-state fermentation (SFF) of low cost substrates by fungal species to generate organic acid solutions for washing of lead from a contaminated soil was evaluated in this study. SFF filtrates were generated by fermentation of four substrates (corn cobs, apple pomace, rice and hay) with three fungal species (Aspergillus niger NRRL 2001 (A. niger 1), Aspergillus niger ATCC 64065 (A. niger 2), Aspergillus foetidus NRRL 337) at three fermentation times. The concentration and speciation of organic acids of the filtrates was found to be a function of the substrate type, the fungal species and the fermentation time. Fermentation of rice resulted in the highest concentrations of citric acid while fermentation of corn cobs, apple pomace and hay tended to generate oxalic acid with an increasing fraction of this acid as the fermentation progressed. Batch extraction tests that employed the SSF filtrates revealed that soluble lead concentrations as high as 35 mg/l could be achieved. Filtrates containing elevated concentrations of citric acid resulted in the greatest lead extraction while oxalic acid inhibited solubilization. Due to the buffering of pH that was provided by the soil in the batch tests this factor did not appear to influence lead extraction. Lead extraction was observed over an extended period of time in a column test. Lead extraction was strongly influenced by the pH of the soil column and less strongly influenced by the organic acid content of the SSF filtrate. The speciation of organic acids was substantially modified from primarily citric acid in the SSF filtrate to gluconic acid in the soil column discharge.