Development of an analytical method for 3-monochloropropane-1, 2-diol in soy sauce using 4-heptanone as derivatizing agent

3-Monochloro-1,2-propane diol is a suspected carcinogen found in hydrolysed vegetable protein products such as soy sauce. A method is described for the analysis of 3-monochloro-1,2-propane diol in soy sauce by gas chromatography-mass spectrometry at a concentration range of 1–5000 ng g−1 using 4-heptanone as the derivatizing ketone and 3-monochloro-1,2-propane diol-d5 as the internal standard. The limit of detection for the method in the soy sauce matrix was 0.48 ng g−1 and the limit of quantification was 1.2 ng g−1

A versatile and scalable strategy for glycoprofiling bifidobacterial consumption of human milk oligosaccharides.

Human milk contains approximately 200 complex oligosaccharides believed to stimulate the growth and establishment of a protective microbiota in the infant gut. The lack of scalable analytical techniques has hindered the measurement of bacterial metabolism of these and other complex prebiotic oligosaccharides. An in vitro, multi-strain, assay capable of measuring kinetics of bacterial growth and detailed oligosaccharide consumption analysis by FTICR-MS was developed and tested simultaneously on 12 bifidobacterial strains. For quantitative consumption, deuterated and reduced human milk oligosaccharide (HMO) standards were used. A custom software suite developed in house called Glycolyzer was used to process the large amounts of oligosaccharide mass spectra automatically with (13)C corrections based on de-isotoping protocols. High growth on HMOs was characteristic of Bifidobacterium longum biovar infantis strains, which consumed nearly all available substrates, while other bifidobacterial strains tested, B. longum bv. longum, B. adolescentis, B. breve and B. bifidum, showed low or only moderate growth ability. Total oligosaccharide consumption ranged from a high of 87% for B. infantis JCM 7009 to only 12% for B. adolescentis ATCC 15703. A detailed analysis of consumption glycoprofiles indicated strain-specific capabilities towards differential metabolism of milk oligosaccharides. This method overcomes previous limitations in the quantitative, multi-strain analysis of bacterial metabolism of HMOs and represents a novel approach towards understanding bacterial consumption of complex prebiotic oligosaccharides

Mucopolysaccharidosis type I, unique structure of accumulated heparan sulfate and increased N-sulfotransferase activity in mice lacking α-L-iduronidase

Mucopolysaccharide (MPS) diseases are characterized by accumulation of glycosaminoglycans (GAGs) due to deficiencies in lysosomal enzymes responsible for GAG breakdown. Using a murine model of MPSI Hurler (MPSIH), we have quantified the heparan sulfate (HS) accumulation resulting from α-l-iduronidase (Idua) deficiency. HS levels were significantly increased in liver and brain tissue from 12-week-old Idua(−/−) mice by 87- and 20-fold, respectively. In addition, HS chains were shown to contain significantly increased N-, 2-O-, and 6-O-sulfation. Disaccharide compositional analyses also uncovered an HS disaccharide uniquely enriched in MPSIH, representing the terminal iduronic acid residue capping the non-reducing end of the HS chain, where no further degradation can occur in the absence of Idua. Critically, we identified that excess HS, some of which is colocalized to the Golgi secretory pathway, acts as a positive regulator of HS-sulfation, increasing the N-sulfotransferase activity of HS-modifying N-deacetylase/N-sulfotransferase enzymes. This mechanism may have severe implications during disease progression but, now identified, could help direct improved therapeutic strategies

The bipolar assembly domain of the mitotic motor kinesin-5.

An outstanding unresolved question is how does the mitotic spindle utilize microtubules and mitotic motors to coordinate accurate chromosome segregation during mitosis? This process depends upon the mitotic motor, kinesin-5, whose unique bipolar architecture, with pairs of motor domains lying at opposite ends of a central rod, allows it to crosslink microtubules within the mitotic spindle and to coordinate their relative sliding during spindle assembly, maintenance and elongation. The structural basis of kinesin-5's bipolarity is, however, unknown, as protein asymmetry has so far precluded its crystallization. Here we use electron microscopy of single molecules of kinesin-5 and its subfragments, combined with hydrodynamic analysis plus mass spectrometry, circular dichroism and site-directed spin label electron paramagnetic resonance spectroscopy, to show how a staggered antiparallel coiled-coil 'BASS' (bipolar assembly) domain directs the assembly of four kinesin-5 polypeptides into bipolar minifilaments