Analysis of allelic variants in the catalase gene in patients with the skin depigmenting disorder vitiligo

Vitiligo is an acquired hypomelanotic skin disorder characterised by circumscribed depigmented macules resulting from the loss of functional melanocytes from the cutaneous epidermis. Conditions that might result in epidermal oxidative stress and consequently damage to pigment cells have been reported in the skin of vitiligo patients, including low catalase activity and increases in hydrogen peroxide levels. However, the cause of the decrease in catalase activity has not been equivocally determined. Several allelic variants in the catalase gene, a number of which have deleterious effects upon the expression or function of the enzyme, have been described and the aim of the present work was to assess the relevance of catalase gene variants in patients with vitiligo. Associations between ten separate allelic variants in the catalase gene and a predisposition to vitiligo were investigated in case-control studies with 166 English patients and 169 ethnically-matched controls using DNA sequencing and restriction fragment length polymorphism-polymerase chain reaction methods. Of the ten allelic variants analysed, only a C/T single nucleotide polymorphism in exon 9 of the catalase gene was associated with vitiligo. The C/T genotype was significantly over-represented in the vitiligo patient group compared with the control cohort. Of 166 vitiligo genotypes, 66 (39.8%) had the C/T variant compared to 45/169 (26.6%) control genotypes (P = 0.030). No evidence for an association between other allelic variants in the catalase gene and vitiligo susceptibility was found. The low catalase activity in vitiligo patient epidermis is more likely to result from environmental conditions such as inhibitory levels of hydrogen peroxide rather than allelic variations in the catalase gene which affect either expression or function of the enzyme.     

Ceramides reduce CD36 cell surface expression and oxidised LDL uptake by monocytes and macrophages

Transglycosylation activity of endo-beta-N-acetylglucosaminidase HS (Endo HS) was investigated using native human transferrin as a donor of an asparagine-linked oligosaccharide and p-nitrophenyl-beta-d-glucose (PNP-beta-d-Glc) as an acceptor of the oligosaccharide. The amount of the product increased dependent on the concentration of the acceptors. Absorption spectrum, exoglycosidase digestion and matrix assisted laser desorption and ionization-time of flight (MALDI-TOF) mass analysis of the transglycosylation product indicated that the asialobiantennary complex type oligosaccharide of human transferrin was transferred to PNP-beta-d-Glc. Endo HS also transferred the oligosaccharide of human transferrin to PNP-alpha-d-Glc, PNP-alpha-d-Gal, PNP-beta-d-Gal, PNP-beta-d-Man, PNP-beta-d-Xyl, PNP-beta-d-GlcNAc, and PNP-glycerol at a different rate. No apparent difference in the K(m) value for human transferrin as an oligosaccharide donor was observed using different acceptors, PNP-beta-d-Glc and PNP-glycerol. The amount of the transglycosylation product successively increased and became constant and then very slightly decreased during the course of enzyme reaction. Endo HS was also transferred the triantennary complex type oligosaccharide of calf fetuin and the bi-, tri-, and tetrantennary complex type oligosaccharides of human alpha(1)-acid glycoprotein to PNP-beta-d-Glc. Furthermore, Endo HS transferred an asparagine-linked oligosaccharide from a hen egg glycopeptide to PNP-beta-d-Glc. The results demonstrate that Endo HS can transfer a wide variety of asparagine-linked complex type oligosaccharides to various monosaccharides. Endo HS was distinct from other enzymes in the specificity for oligosaccharide donors and acceptors.     

Predictors of belief that genetic test information about hemochromatosis should be shared with family members

We queried 101,951 white, Hispanic, black, Asian, American Indian (i.e., American Indian or Alaska Native in the United States and North American Indian, Metis, or Inuit in Canada) and Pacific Islander (including Native Hawaiian) adults who agreed to be genotypically and phenotypically screened for hemochromatosis as part of the Hemochromatosis and Iron Overload Screening (HEIRS) study about their views on sharing genetic test information with family members. Multiple logistic regression (adjusting for study site, age group, race/ethnicity, preferred language, gender, education group, income group, SF-36 General Health and Mental Health subscales, perceived benefits and limitations of genetic testing, and belief that genetic testing is a good idea) evaluated independent predictors of responding "Strongly Agree" or "Agree" versus "Disagree" or "Strongly Disagree" to the statement "Information about a person's genetic risk should be shared with family members". Agreement that genetic risk information should be shared with family members was high (93% in the overall sample of 78,952 who answered this question), but differed among racial/ethnic groups. Hispanics were significantly less likely to agree that genetic test information should be shared with family members (i.e., 88% versus 92% or more among all other ethnicities). The relationship of perceived limitations and benefits of testing, gender, and age group to the belief that information should be shared differed among racial/ethnic groups, with Spanish-preferring Hispanics being the most different from other subgroups.     

In situ trapping of activated initiator caspases reveals a role for caspase-2 in heat shock-induced apoptosis

Activation of 'initiator' (or 'apical') caspases-2, -8 or -9 (refs 1-3) is crucial for induction of apoptosis. These caspases function to activate executioner caspapses that, in turn, orchestrate apoptotic cell death. Here, we show that a cell-permeable, biotinylated pan-caspase inhibitor (bVAD-fmk) both inhibited and 'trapped' the apical caspase activated when apoptosis was triggered. As expected, only caspase-8 was trapped in response to ligation of death receptors, whereas only caspase-9 was trapped in response to a variety of other apoptosis-inducing agents. Caspase-2 was exclusively activated in heat shock-induced apoptosis. This activation of caspase-2 was also observed in cells protected from heat-shock-induced apoptosis by Bcl-2 or Bcl-xL. Reduced sensitivity to heat-shock-induced death was observed in caspase-2(-/-) cells. Furthermore, cells lacking the adapter molecule RAIDD failed to activate caspase-2 after heat shock treatment and showed resistance to apoptosis in this setting. This approach unambiguously identifies the apical caspase activated in response to apoptotic stimuli, and establishes caspase-2 as a proximal mediator of heat shock-induced apoptosis.     

Biosynthesis of hopanoids by sulfate-reducing bacteria (genus Desulfovibrio)

Sulfate reduction accounts for about a half of the remineralization of organic carbon in anoxic marine shelf regions. Moreover, it was already a major microbial process in the very early ocean at least 2.4 billion years before the present. Here we demonstrate for the first time the capability of sulfate-reducing bacteria (SRB) to biosynthesize hopanoids, compounds that are quantitatively important and widely distributed biomarkers in recent and fossil sediments dating back to the late Archean. We found high concentrations (9.8-12.3 mg per gram of dry cells) of non-extended and extended bacteriohopanoids (bacteriohopanetetrol, aminobacteriohopanetriol, aminobacteriohopanetetrol) in pure cultures of SRB belonging to the widely distributed genus Desulfovibrio. Biohopanoids were found--considered as membrane rigidifiers--in more than 50% of bacterial species analysed so far. However, their biosynthesis appeared to be restricted to aerobes or facultative anaerobes with a very few recently described exceptions. Consequently, findings of sedimentary hopanoids are often used as indication for oxygenated settings. Nevertheless, our findings shed new light on the presence of hopanoids in specific anoxic settings and suggests that SRB are substantial sources of this quantitatively important lipid class in recent but also past anoxic environments.     

WholePathwayScope: a comprehensive pathway-based analysis tool for high-throughput data

Background  

Analysis of High Throughput (HTP) Data such as microarray and proteomics data has provided a powerful methodology to study patterns of gene regulation at genome scale. A major unresolved problem in the post-genomic era is to assemble the large amounts of data generated into a meaningful biological context. We have developed a comprehensive software tool, WholePathwayScope (WPS), for deriving biological insights from analysis of HTP data.     

Split centromeric alpha-satellite FISH signals in a whole arm translocation 5p;10p: consequences and implications for interphase FISH studies

This is a case report of an apparently balanced whole arm translocation between the short arms of chromosomes 5 and 10 in which the centromeric alpha-satellite DNA is split between both derivative chromosomes for both probes, leading to abnormal signal patterns. The patient requested preimplantation genetic testing for the unbalanced products of the translocation. However, using centromeric alpha-satellite DNA probes as controls for the subtelomeric-specific probes in interphase was not informative because of the split signals. The ramifications of such variation in the alpha-satellite regions of chromosomes for other interphase FISH tests are discussed.