Nitroreductase Activites in Giardia lamblia: ORF 17150 Encodes a Quinone Reductase with Nitroreductase Activity

The intestinal diplomonadid Giardia lamblia is a causative agent of persistent diarrhea. Current treatments are based on nitro drugs, especially metronidazole. Nitro compounds are activated by reduction, yielding toxic intermediates. The enzymatic systems responsible for this activation are not completely understood. By fractionating cell free crude extracts by size exclusion chromatography followed by mass spectrometry, enzymes with nitroreductase (NR) activities are identified. The protein encoded by ORF 17150 found in two pools with NR activities is overexpressed and characterized. In pools of fractions with main NR activities, previously-known NRs are identified, as well as a previously uncharacterized protein encoded by ORF 17150. Recombinant protein 17150 is a flavoprotein with NADPH-dependent quinone reductase and NR activities. Besides a set of previously identified NRs, we have identified a novel enzyme with NR activity.

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Comparison of differential ultracentrifugation (DC) and size exclusion chromatography (SEC) based exosome isolation methods

10.1055/s-0038-1645025 ◽

2018 ◽

Author(s):

S Strachan ◽

E Kontopoulou ◽

D Reinhardt ◽

B Giebel ◽

B Thakur

Keyword(s):

Size Exclusion Chromatography ◽

Size Exclusion ◽

Isolation Methods ◽

Exclusion Chromatography

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CHARACTERIZATION OF A NEW LCAT MUTATION CAUSING FAMILIAL LCAT DEFICIENCY (FLD) AND THE ROLE OF APOE AS A MODIFIER GENE OF THE FLD PHENOTYPE

Clinical & Investigative Medicine ◽

10.25011/cim.v32i6s.11137 ◽

2009 ◽

Vol 32 (6S) ◽

pp. 3

Author(s):

A Baass ◽

H Wassef ◽

M Tremblay ◽

L Bernier ◽

R Dufour ◽

...

Keyword(s):

Modifier Gene ◽

Size Exclusion ◽

Plasma Lipoproteins ◽

Lipoprotein Profile ◽

Exclusion Chromatography ◽

Low Hdl ◽

Lcat Deficiency ◽

Apoe Genotypes

Introduction: LCAT (lecithin:cholesterol acyltransferase ) is an enzyme which plays an essential role in cholesterol esterification and reverse cholesterol transport. Familial LCAT deficiency (FLD) is a disease characterized by a defect in LCAT resulting in extremely low HDL-C, premature corneal opacities, anemia as well as proteinuria and renal failure. Method: We have identified two brothers presenting characteristics of familial LCAT deficiency. We sequenced the LCAT gene, measured the lipid profile as well as the LCAT activity in 15 members of this kindred. We also characterized the plasma lipoproteins by agarose gel electrophoresis and size exclusion chromatography and sequenced several candidate genes related to dysbetalipoproteinemia in this family. Results: We have identified the first French Canadian kindred with familial LCAT deficiency. Two brothers affected by FLD, were homozygous for a novel LCAT mutation. This c.102delG mutation occurs at the codon for His35 causing a frameshift that stops transcription at codon 61 abolishing LCAT enzymatic activity both in vivo and in vitro. It has a dramatic effect on the lipoprotein profile, with an important reduction of HDL-C in both heterozygotes (22%) and homozygotes (88%) and a significant decrease in LDL-C in heterozygotes (35%) as well as homozygotes (58%). Furthermore, the lipoprotein profile differed markedly between the two affected brothers who had different APOE genotypes. We propose that APOE could be an important modifier gene explaining heterogeneity in lipoprotein profiles observed among FLD patients. Our results suggest that a LCAT-/- genotype associated with an APOE ?2 allele could be a novel mechanism leading to dysbetalipoproteinemia.

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Structure of a shear-thickening polysaccharide extracted from the New Zealand black tree fern, Cyathea medullaris

10.26686/wgtn.12597809.v1 ◽

2020 ◽

Author(s):

M Wee ◽

M Mastrangelo ◽

Susan Carnachan ◽

Ian Sims ◽

K Goh

Keyword(s):

New Zealand ◽

Uronic Acid ◽

Average Molecular Weight ◽

Shear Thickening ◽

Water Soluble ◽

Size Exclusion ◽

Resonance Spectroscopy ◽

Tree Fern ◽

13C Nuclear Magnetic Resonance ◽

Exclusion Chromatography

A shear-thickening water-soluble polysaccharide was purified from mucilage extracted from the fronds of the New Zealand black tree fern (Cyathea medullaris or 'mamaku' in Māori) and its structure characterised. Constituent sugar analysis by three complementary methods, combined with linkage analysis (of carboxyl reduced samples) and 1H and 13C nuclear magnetic resonance spectroscopy (NMR) revealed a glucuronomannan comprising a backbone of 4-linked methylesterified glucopyranosyl uronic acid and 2-linked mannopyranosyl residues, branched at O-3 of 45% and at both O-3 and O-4 of 53% of the mannopyranosyl residues with side chains likely comprising terminal xylopyranosyl, terminal galactopyranosyl, non-methylesterified terminal glucopyranosyl uronic acid and 3-linked glucopyranosyl uronic acid residues. The weight-average molecular weight of the purified polysaccharide was ~1.9×106Da as determined by size-exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALLS). The distinctive rheological properties of this polysaccharide are discussed in relation to its structure. © 2014 Elsevier B.V.

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