Roma women in Athenian firms: do they face wage bias?

In the current study, we analyse the effect of having a Roma background on women's wages. By utilizing data from sixteen multiethnic municipalities in which Roma live, we estimate that 66.2 per cent of the wage differential between Roma and non-Roma female workers cannot be explained by differences in observed characteristics. Prejudices against Roma women are discussed and appear to explain the wage gap found here. The occupational segregation of the Roma in low-paid jobs and employers' statistical motivations are also found to influence wages earned by Roma. This study concludes that there is a need for better implementation of existing laws, rules and regulations, which would counter the discrimination against minority women in the labour market. In addition, a better means of assessing workers' skills might contribute to the reduction of wage discrimination, and greater educational achievement would significantly boost the economic status of Roma women.     

Stability of ultramer as copy number standards in real-time PCR

Since commercial copy number standards are not always available for real-time PCR, alternative sources of DNA are used. Unfortunately, stored genomic DNA or PCR amplicon has been shown to be unstable, resulting in variable copy number. More recently, the use of ultramer as copy number standard has been reported. However, there is little information on the stability of ultramer under different storage conditions. Thus the aim of this study was to determine the stability of ultramer as copy number standard under different storage conditions using different mixing methods. We found that ultramer copy number was not affected by storage at either 4 °C or − 20 °C over a period of 30 days. Furthermore, the method of mixing the ultramer did not appear to contribute to variability in results. Irrespective of storage temperature or mixing method, there was less than 5% variance in Ct value over a period of 30 days. A duplicate set of standards costs approximately $0.01. Therefore, the use of ultramer as copy number standards in real-time PCR, is cost effective and convenient.     

Different coexpressions of arthritis-relevant genes between different body organs and different brain regions in the normal mouse population

Structural changes in different parts of the brain in rheumatoid arthritis (RA) patients have been reported. RA is not regarded as a brain disease. Body organs such as spleen and lung produce RA-relevant genes. We hypothesized that the structural changes in the brain are caused by changes of gene expression in body organs. Changes in different parts of the brain may be affected by altered gene expressions in different body organs. This study explored whether an association between gene expressions of an organ or a body part varies in different brain structures. By examining the association of the 10 most altered genes from a mouse model of spontaneous arthritis in a normal mouse population, we found two groups of gene expression patterns between five brain structures and spleen. The correlation patterns between the prefrontal cortex, nucleus accumbens, and spleen were similar, while the associations between the other three parts of the brain and spleen showed a different pattern. Among overall patterns of the associations between body organs and brain structures, spleen and lung had a similar pattern, and patterns for kidney and liver were similar. Analysis of the five additional known arthritis-relevant genes produced similar results. Analysis of 10 nonrelevant-arthritis genes did not result in a strong association of gene expression or clearly segregated patterns. Our data suggest that abnormal gene expressions in different diseased body organs may influence structural changes in different brain parts.     

Contribution of genetic and epigenetic mechanisms to Wnt pathway activity in prevalent skeletal disorders

We reported previously that the expression of Wnt-related genes is lower in osteoporotic hip fractures than in osteoarthritis. We aimed to confirm those results by analyzing β-catenin levels and explored potential genetic and epigenetic mechanisms involved.     

Modelling family 2 cystatins and their interaction with papain

Cystatins are extensively studied cysteine protease inhibitors, found in wide range of organisms with highly conserved structural folds. S-type of cystatins is well known for their abundance in saliva, high selectivity and poorer activity towards host cysteine proteases in comparison to their immediate ancestor cystatin C. Despite more than 90% sequence similarity, the members of this group show highly dissimilar binding affinity towards papain. Cystatin M/E is a potent inhibitor of legumain and papain like cysteine proteases and recognized for its involvement in skin barrier formation and potential role as a tumor suppressor gene. However, the structures of these proteins and their complexes with papain or legumain are still unknown. In the present study, we have employed computational methods to get insight into the interactions between papain and cystatins. Three-dimensional structures of the cystatins are generated by homology modelling, refined with molecular dynamics simulation, validated through numerous web servers and finally complexed with papain using ZDOCK algorithm in Discovery Studio. A high degree of shape complementarity is observed within the complexes, stabilized by numerous hydrogen bonds (HB) and hydrophobic interactions. Using interaction energy, HB and solvent accessible surface area analyses, we have identified a series of key residues that may be involved in papain–cystatin interaction. Differential approaches of cystatins towards papain are also noticed which are possibly responsible for diverse inhibitory activity within the group. These findings will improve our understanding of fundamental inhibitory mechanisms of cystatin and provide clues for further research.     

Crystal structure of the CN-hydrolase SA0302 from the pathogenic bacterium Staphylococcus aureus belonging to the Nit and NitFhit Branch of the nitrilase superfamily

The nitrilases include a variety of enzymes with functional specificities of nitrilase, amidase, and hydrolase reactions. The crystal structure of the uncharacterized protein SA0302 from the pathogenic microorganism Staphylococcus aureus is solved at 1.7?Å resolution. The protein contains 261 amino acids and presents a four-layer αββα sandwich with a chain topology similar to that of a few known CN-hydrolase folds. In the crystal, the proteins are arranged as dimers whose monomers are related by a pseudo twofold rotation symmetry axis. Analysis of the sequences and structures of CN-hydrolases with known 3D structures shows that SA0302 definitely is a member of Branch 10 (Nit and NitFhit) of the nitrilase superfamily. Enzyme activities and substrate specificities of members of this branch are not yet characterized, in contrast to those of the members of Branches 1–9. Although the sequence identities between Branch 10 members are rather low, less than 30%, five conserved regions are common in this subfamily. Three of them contain functionally important catalytic residues, and the two other newly characterized ones are associated with crucial intramolecular and intermolecular interactions. Sequence homology of the area near the active site shows clearly that the catalytic triad of SA0302 is Glu41-Lys110-Cys146. We suggest also that the active site includes a fourth residue, the closely located Glu119. Despite an extensive similarity with other Nit-family structural folds, SA0302 displays an important difference. Protein loop 111–122, which follows the catalytic Lys110, is reduced to half the number of amino acids found in other Nit-family members. This leaves the active site fully accessible to solvent and substrates. We have identified conservative sequence motifs around the three core catalytic residues, which are inherent solely to Branch 10 of the nitrilase superfamily. On the basis of these new sequence fingerprints, 10 previously uncharacterized proteins also could be assigned to this hydrolase subfamily.

An animated interactive 3D complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:19     

The Modular Organisation and Stability of a Thermostable Family 10 Xylanase

The thermophilic marine bacterium Rhodothermus marinus produces a modular family 10 xylanase (Xyn10A). It consists of two N-terminal family 4 carbohydrate binding modules (CBMs) followed by a domain of unknown function (D3), and a catalytic module (CM) flanked by a small fifth domain (D5) at its C-terminus. Several truncated mutants of the enzyme have been produced and characterised with respect to biochemical properties and stability. Multiple calcium binding sites are shown to be present in the two N-terminal CBMs and recent evidence suggests that the third domain of the enzyme also has the ability to bind the same metal ligand. The specific binding of Ca²⁺ was demonstrated to have a pronounced effect on thermostability as shown by differential scanning calorimetry and thermal inactivation studies. Furthermore, deletion mutants of the enzyme were less stable than the full-length enzyme suggesting that module interactions contributed to the stability of the enzyme. Finally, recent evidence indicates that the fifth domain of Xyn10A is a novel type of module mediating cell-attachment.     

Glycoside hydrolase family 31 Escherichia coli α-xylosidase

Escherichia coli YicI is a retaining α-xylosidase, which strictly recognizes the α-xylosyl moiety at the non-reducing end, belonging to glycoside hydrolase family 31 (GH 31). We have elucidated key residues determining the substrate specificity at both glycone and aglycone sites of Escherichia coli α-xylosidase (YicI). Detection of distinguishing features between α-xylosidases and α-glucosidases of GH 31 in their close evolutionary relationship has been used for the modification of protein function, converting YicI into an α-glucosidase. Aglycone specificity has been characterized by its transxylosylation ability. YicI exhibits a preference for aldopyranosyl sugars having equatorial 4-OH as the acceptor substrate with 1,6 regioselectivity, resulting in transfer products. The disaccharide transfer products of YicI, α-d-Xylp-(1→6)-d-Manp, α-d-Xylp-(1→6)-d-Fruf, and α-d-Xylp-(1→3)-d-Frup, are novel oligosaccharides, which have never been reported. The transxylosylation products are moderately inhibitory towards intestinal α-glucosidases.