134 research outputs found
A dedicated haem lyase is required for the maturation of a novel bacterial cytochrome c with unconventional covalent haem binding
In bacterial c-type cytochromes, the haem cofactor is covalently attached via two cysteine residues organized in a haem c-binding motif. Here, a novel octa-haem c protein, MccA, is described that contains only seven conventional haem c-binding motifs (CXXCH), in addition to several single cysteine residues and a conserved CH signature. Mass spectrometric analysis of purified MccA from Wolinella succinogenes suggests that two of the single cysteine residues are actually part of an unprecedented CX15CH sequence involved in haem c binding. Spectroscopic characterization of MccA identified an unusual high-potential haem c with a red-shifted absorption maximum, not unlike that of certain eukaryotic cytochromes c that exceptionally bind haem via only one thioether bridge. A haem lyase gene was found to be specifically required for the maturation of MccA in W. succinogenes. Equivalent haem lyase-encoding genes belonging to either the bacterial cytochrome c biogenesis system I or II are present in the vicinity of every known mccA gene suggesting a dedicated cytochrome c maturation pathway. The results necessitate reconsideration of computer-based prediction of putative haem c-binding motifs in bacterial proteomes
A 1-D modelling of streaming potential dependence on water content during drainage experiment in sand
The understanding of electrokinetics for unsaturated conditions is crucial
for numerous of geophysical data interpretation. Nevertheless, the behaviour of
the streaming potential coefficient C as a function of the water saturation Sw
is still discussed. We propose here to model both the Richards' equation for
hydrodynamics and the Poisson's equation for electrical potential for
unsaturated conditions using 1-D finite element method. The equations are first
presented and the numerical scheme is then detailed for the Poisson's equation.
Then, computed streaming potentials (SPs) are compared to recently published SP
measurements carried out during drainage experiment in a sand column. We show
that the apparent measurement of DV / DP for the dipoles can provide the SP
coefficient in these conditions. Two tests have been performed using existing
models for the SP coefficient and a third one using a new relation. The results
show that existing models of unsaturated SP coefficients C(Sw) provide poor
results in terms of SP magnitude and behaviour. We demonstrate that the
unsaturated SP coefficient can be until one order of magnitude larger than
Csat, its value at saturation. We finally prove that the SP coefficient follows
a non-monotonous behaviour with respect to water saturation. Key words:
Electrical properties; Electromagnetic theory; Hydrogeophysics; Hydrology;
Permeability and porosity; electrokinetic; streaming potential; self-potential;
water content; water saturation; unsaturated condition; finite element modelin
Heterogeneous clinical spectrum of DNAJC12-deficient hyperphenylalaninemia:From attention deficit to severe dystonia and intellectual disability
BACKGROUND: Autosomal recessive mutations in DNAJC12, encoding a cochaperone of HSP70 with hitherto unknown function, were recently described to lead to hyperphenylalaninemia, central monoamine neurotransmitter (dopamine and serotonin) deficiency, dystonia and intellectual disability in six subjects affected by homozygous variants.
OBJECTIVE: Patients exhibiting hyperphenylalaninemia in whom deficiencies in hepatic phenylalanine hydroxylase and tetrahydrobiopterin cofactor metabolism had been excluded were subsequently analysed for DNAJC12 variants.
METHODS: To analyse DNAJC12, genomic DNA from peripheral blood (Sanger sequencing), as well as quantitative messenger RNA (Real Time Quantitative Polymerase Chain Reaction (RT-qPCR)) and protein expression (Western blot) from primary skin fibroblasts were performed.
RESULTS: We describe five additional patients from three unrelated families with homozygosity/compound heterozygosity in DNAJC12 with three novel variants: c.85delC/p.Gln29Lysfs*38, c.596G>T/p.*199Leuext*42 and c.214C>T/p.(Arg72*). In contrast to previously reported DNAJC12-deficient patients, all five cases showed a very mild neurological phenotype. In two subjects, cerebrospinal fluid and primary skin fibroblasts were analysed showing similarly low 5-hydroxyindolacetic acid and homovanillic acid concentrations but more reduced expressions of mRNA and DNAJC12 compared with previously described patients. All patients responded to tetrahydrobiopterin challenge by lowering blood phenylalanine levels.
CONCLUSIONS: DNAJC12 deficiency appears to result in a more heterogeneous neurological phenotype than originally described. While early identification and institution of treatment with tetrahydrobiopterin and neurotransmitter precursors is crucial to ensure optimal neurological outcome in DNAJC12-deficient patients with a severe phenotype, optimal treatment for patients with a milder phenotype remains to be defined
Subclavian thrombosis in a patient with advanced lung cancer: a case report
<p>Abstract</p> <p>Introduction</p> <p>Lung cancer is now considered the most common cause of death among cancer patients. Although target biological regimens have emerged in recent years for non-small cell lung carcinoma, the survival and quality of life of patients with this condition still remain low. The five-year survival rate for all stages of lung cancer is 17% or less.</p> <p>Case presentation</p> <p>We describe the case of a 53-year-old Caucasian woman who was diagnosed with advanced stage IIIa (T2aN<sub>2</sub>M<sub>0</sub>) non-small cell lung carcinoma (adenocarcinoma) and underwent a complete left upper lobectomy three years ago. After two and a half years of follow-up, she suddenly presented with facial edema and venous distension and was immediately treated for superior vena cava syndrome. Because of a diagnostic check, a major clot was detected in the right subclavian vein. Our patient was informed about treatment options, and she was taken to the catheterization laboratory for percutaneous stenting of the superior vena cava to restore superior vena cava patency.</p> <p>Conclusion</p> <p>Lung cancer has a vast number of complications. Superior vena cava syndrome and thrombosis should be considered upon the presentation of a patient with obstructive symptoms. In this case report, even though we expected the clot to be on the side of the former lesion, it was present on the opposite side. Treatment should also start immediately in these patients with clinical suspicion of thrombosis to avoid further complications, even in cases with a differential diagnosis problem. Finally, although patients with non-small cell lung carcinoma have a high incidence of thromboembolic events, anticoagulant treatment is given only as maintenance therapy after a first event occurs.</p
Consensus guideline for the diagnosis and treatment of tetrahydrobiopterin (BH4) deficiencies
Background: Tetrahydrobiopterin (BH4) deficiencies comprise a group of six rare neurometabolic disorders characterized by insufficient synthesis of the monoamine neurotransmitters dopamine and serotonin due to a disturbance of BH4 biosynthesis or recycling. Hyperphenylalaninemia (HPA) is the first diagnostic hallmark for most BH4 deficiencies, apart from autosomal dominant guanosine triphosphate cyclohydrolase I deficiency and sepiapterin reductase deficiency. Early supplementation of neurotransmitter precursors and where appropriate, treatment of HPA results in significant improvement of motor and cognitive function. Management approaches differ across the world and therefore these guidelines have been developed aiming to harmonize and optimize patient care. Representatives of the International Working Group on Neurotransmitter related Disorders (iNTD) developed the guidelines according to the SIGN (Scottish Intercollegiate Guidelines Network) methodology by evaluating all available evidence for the diagnosis and treatment of BH4 deficiencies. Conclusion: Although the total body of evidence in the literature was mainly rated as low or very low, these consensus guidelines will help to harmonize clinical practice and to standardize and improve care for BH4 deficient patients
The Genetic Landscape and Epidemiology of Phenylketonuria
Phenylketonuria (PKU), caused by variants in the phenylalanine hydroxylase (PAH) gene, is the most common autosomal-recessive Mendelian phenotype of amino acid metabolism. We estimated that globally 0.45 million individuals have PKU, with global prevalence 1:23,930 live births (range 1:4,500 [Italy]-1:125,000 [Japan]). Comparing genotypes and metabolic phenotypes from 16,092 affected subjects revealed differences in disease severity in 51 countries from 17 world regions, with the global phenotype distribution of 62% classic PKU, 22% mild PKU, and 16% mild hyperphenylalaninemia. A gradient in genotype and phenotype distribution exists across Europe, from classic PKU in the east to mild PKU in the southwest and mild hyperphenylalaninemia in the south. The c.1241A gt G (p.Tyr414Cys)-associated genotype can be traced from Northern to Western Europe, from Sweden via Norway, to Denmark, to the Netherlands. The frequency of classic PKU increases from Europe (56%) via Middle East (71%) to Australia (80%). Of 758 PAH variants, c.1222C gt T (p.Arg408Trp) (22.2%), c.1066-11G gt A (IVS10-11G gt A) (6.4%), and c.782G gt A (p.Arg261Gln) (5.5%) were most common and responsible for two prevalent genotypes: p.[Arg408Trp];[Arg408Trp] (11.4%) and c.[1066-11G gt A];[1066-11G gt A] (2.6%). Most genotypes (73%) were compound heterozygous, 27% were homozygous, and 55% of 3,659 different genotypes occurred in only a single individual. PAH variants were scored using an allelic phenotype value and correlated with pre-treatment blood phenylalanine concentrations (n = 6,115) and tetrahydrobiopterin loading test results (n = 4,381), enabling prediction of both a genotype-based phenotype (88%) and tetrahydrobiopterin responsiveness (83%). This study shows that large genotype databases enable accurate phenotype prediction, allowing appropriate targeting of therapies to optimize clinical outcome
Genome-Wide Identification of Transcriptional Start Sites in the Plant Pathogen Pseudomonas syringae pv. tomato str. DC3000
RNA-Seq has provided valuable insights into global gene expression in a wide variety of organisms. Using a modified RNA-Seq approach and Illumina's high-throughput sequencing technology, we globally identified 5′-ends of transcripts for the plant pathogen Pseudomonas syringae pv. tomato str. DC3000. A substantial fraction of 5′-ends obtained by this method were consistent with results obtained using global RNA-Seq and 5′RACE. As expected, many 5′-ends were positioned a short distance upstream of annotated genes. We also captured 5′-ends within intergenic regions, providing evidence for the expression of un-annotated genes and non-coding RNAs, and detected numerous examples of antisense transcription, suggesting additional levels of complexity in gene regulation in DC3000. Importantly, targeted searches for sequence patterns in the vicinity of 5′-ends revealed over 1200 putative promoters and other regulatory motifs, establishing a broad foundation for future investigations of regulation at the genomic and single gene levels
Genome analysis and physiological comparison of Alicycliphilus denitrificans strains BC and K601T
The genomes of the Betaproteobacteria Alicycliphilus denitrificans strains BC and K601T have been sequenced to get insight into the physiology of the two strains. Strain BC degrades benzene with chlorate as electron acceptor. The cyclohexanol-degrading denitrifying strain K601T is not able to use chlorate as electron acceptor, while strain BC cannot degrade cyclohexanol. The 16S rRNA sequences of strains BC and K601T are identical and the fatty acid methyl ester patterns of the strains are similar. Basic Local Alignment Search Tool (BLAST) analysis of predicted open reading frames of both strains showed most hits with Acidovorax sp. JS42, a bacterium that degrades nitro-aromatics. The genomes include strain-specific plasmids (pAlide201 in strain K601T and pAlide01 and pAlide02 in strain BC). Key genes of chlorate reduction in strain BC were located on a 120 kb megaplasmid (pAlide01), which was absent in strain K601T. Genes involved in cyclohexanol degradation were only found in strain K601T. Benzene and toluene are degraded via oxygenase-mediated pathways in both strains. Genes involved in the meta-cleavage pathway of catechol are present in the genomes of both strains. Strain BC also contains all genes of the ortho-cleavage pathway. The large number of mono- and dioxygenase genes in the genomes suggests that the two strains have a broader substrate range than known thus far.This research was supported by the Technology Foundation, the Applied Science Division (STW) of the Netherlands Organization for Scientific Research (NWO), project number 08053, the graduate school WIMEK (Wageningen Institute for Environment and Climate Research, which is part of SENSE Research School for Socio-Economic and Natural Sciences of the Environment, www.wimek-new.wur.nl and www.sense.nl), SKB (Dutch Centre for Soil Quality Management and Knowledge Transfer, www.skbodem.nl) and the Consolider project CSD-2007-00055. The research was incorporated in the TRIAS (TRIpartite Approaches 469 toward Soil systems processes) program (http://www.nwo.nl/en/research-and-results/programmes/alw/trias-tripartite-approach-to-soil-system-processes/index. html). Flávia Talarico Saia was supported by a FAPESP (the State of São Paulo Research Foundation) scholarship (2006-01997/5). The work conducted by the DOE JGI is supported by the Office of Science of the United States Department of Energy under contract number DE-AC02-05CH11231. Alfons Stams acknowledges support by an ERC (European Research Counsil) advanced grant (project 323009). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
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