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Amongst iron-oxidizing bacteria playing a key role in the natural attenuation of arsenic in acid mine drainages (AMDs), members of the Ferrovum genus were identified in mine effluent or water treatment plants, and were shown to dominate biogenic precipitates in field pilot experiments. In order to address the question of the in situ activity of the uncultivated Ferrovum sp. CARN8 strain in the Carnoulès AMD, we assembled its genome using metagenomic and metatranscriptomic sequences and we determined standardized expression values for protein-encoding genes. Our results showed that this microorganism was indeed metabolically active and allowed us to sketch out its metabolic activity in its natural environment. Expression of genes related to the respiratory chain and carbon fixation suggests aerobic energy production coupled to ferrous iron oxidation and chemolithoautotrophic growth. Notwithstanding the presence of nitrogenase genes in its genome, expression data also indicated that Ferrovum sp. CARN8 relied on ammonium import rather than nitrogen fixation. The expression of flagellum and chemotaxis genes hints that at least a proportion of this strain population was motile. Finally, apart from some genes related to metal resistance showing surprisingly low expression values, genes involved in stress response were well expressed as expected in AMDs. [ABSTRACT FROM AUTHOR]

Skin fibroblast cultures from patients with inherited lysosomal enzymopathies, α-N-acetylgalactosaminidase (α-NAGA) and α-galactosidase A deficiencies (Schindler and Fabry disease, respectively), and from normal controls were used to study in situ degradation of blood group A and B glycosphingolipids. Glycosphingolipids A-6-2 (GalNAc (α1→3)[Fucα1→2]Gal(β1→4)GlcNAc(β1→3)Gal(β1→ 4)Glc (β1→1′)Cer, IV2-α-fucosyl-IV3-α-N-acetylgalactosaminylneolactotetraosylceramide), B-6-2 (Gal(α1→3)[Fucα1→ 2] Gal (β1→4)GlcNAc(β1→3)Gal(β1→4)Glc(β1→1′)Cer, IV2- α-fucosyl-IV3-α-galactosylneolactotetraosylceramide), and globoside (GalNAc(β1→3)Gal(α1→4)Gal(β1→4)Glc(β1→1′) Cer, globotetraosylceramide) were tritium labeled in their ceramide moiety and used as natural substrates. The degradation rate of glycolipid A-6-2 was very low in fibroblasts of all the α-NAGA-deficient patients (less than 7% of controls), despite very heterogeneous clinical pictures, ruling out different residual enzyme activities as an explanation for the clinical heterogeneity. Strongly elevated urinary excretion of blood group A glycolipids was detected in one patient with blood group A, secretor status (five times higher than upper limit of controls), in support of the notion that blood group A-active glycolipids may contribute as storage compounds in blood group A patients. When glycolipid B-6-2 was fed to α-galactosidase A-deficient cells, the degradation rate was surprisingly high (50% of controls), while that of globotriaosylceramide was reduced to less than 15% of control average, presumably reflecting differences in the lysosomal enzymology of polar glycolipids versus less-polar ones.Relatively high-degree degradation of substrates with α-d-Galactosyl moieties hints at a possible contribution of other enzymes.

The degradation of blood group glycolipid A-6-2 (GalNAc(α1→3)[Fucα1→2]Gal(β1→4)GlcNAc(β1→3)Gal (β1→4)Glc(β1→1′)Cer, IV2-α-fucosyl-IV3-α-N-acetylgalactosaminylneolactotetraosylceramide), tritium-labeled in its ceramide moiety, was studied in situ, in skin fibroblast cultures from normal controls, from patients with defects of lysosomal α-N-acetylgalactosaminidase, and from patients with other lysosomal storage diseases. Uptake of the glycolipid with apolipoprotein E-coated liposomes was linear with time and with the amount of glycolipid added. In normal cells, the expected array of less polar products and some lipids resulting from re-using the liberated sphingosine, mainly sphingomyelin and phosphatidylcholine, were formed. In α-N-acetylgalactosaminidase-deficient cells, the glycolipid was virtually not degraded; product formation was less than 2% of the normal control rate, suggesting that blood group A-active glycolipids contribute as storage compounds to the pathogenesis of this disease. The expected accumulation of degradation intermediates was seen in fucosidosis, and in Sandhoff, Gaucher, and Farber disease cells, whereas normal turnover rates were found in Tay-Sachs disease cells, GM2 activator-deficient (variant AB of GM2 gangliosidosis) and in sulfatide activator- (sap-B-) deficient cells. In GM1 gangliosidosis and in sap precursor-deficient cells, the lysosomal glycolipid catabolism was found to be strongly retarded; accumulation of individual products could not be seen. Skin fibroblasts from patients with α-N-acetylgalactosaminidase deficiency (Schindler disease) cannot degrade the major blood group A glycolipid.—Asfaw, B., D. Schindler, J. Ledvinová, B. Černý, F. Šmíd, and E. Conzelmann. Degradation of blood group A glycolipid A-6-2 by normal and mutant human skin fibroblasts.

An in situ nuclear magnetic resonance (NMR) bioreactor was developed and employed to monitor microbial metabolism under batch growth conditions in real time. We selected Moorella thermoacetica ATCC 49707 as a test case. M. thermoacetica (formerly Clostridium thermoaceticum) is a strictly anaerobic, thermophilic, acetogenic, gram-positive bacterium with potential for industrial production of chemicals. The metabolic profiles of M. thermoacetica were characterized during growth in batch mode on xylose (a component of lignocellulosic biomass) using the new generation NMR bioreactor in combination with high-resolution NMR (HR-NMR) spectroscopy. In situ NMR measurements were performed using water-suppressed H-1 NMR spectroscopy at 500 MHz, and aliquots of the bioreactor contents were taken for 600-MHz HR-NMR spectroscopy at specific intervals to confirm metabolite identifications and expand metabolite coverage. M. thermoacetica demonstrated the metabolic potential to produce formate, ethanol, and methanol from xylose, in addition to its known capability of producing acetic acid. Real-time monitoring of bioreactor conditions showed a temporary pH decrease, with a concomitant increase in formic acid during exponential growth. Fermentation experiments performed outside of the magnet showed that the strong magnetic field employed for NMR detection did not significantly affect cell metabolism. Use of the in situ NMR bioreactor facilitated monitoring of the fermentation process, enabling identification of intermediate and endpoint metabolites and their correlation with pH and biomass produced during culture growth. Real-time monitoring of culture metabolism using the NMR bioreactor in combination with HR-NMR spectroscopy will allow optimization of the metabolism of microorganisms producing valuable bioproducts. [ABSTRACT FROM AUTHOR]