Simultaneous storage of medical images in the spatial and frequency domain: A comparative study

Background  

Digital watermarking is a technique of hiding specific identification data for copyright authentication. This technique is adapted here for interleaving patient information with medical images, to reduce storage and transmission overheads.     

Randomly distributed crossovers may generate block-like patterns of linkage disequilibrium: an act of genetic drift

There is considerable interest in identifying and characterizing block-like patterns of linkage disequilibrium (LD; haplotype blocks) in the human genome as these may facilitate the identification of complex disease genes via genome-wide association studies. Although recombination hot-spots have been suggested as the primary mechanism to explain the block-like pattern of LD, other forces, such as genetic drift, may also be important. To this end, we have studied the effect of various recombination models on patterns of LD by using extensive simulations. As expected, haplotype blocks were observed under a model allowing recombination hot-spots. However, we also observed similar block-like patterns in the models where recombination crossovers are randomly and uniformly distributed, and we demonstrate that these blocks are generated by genetic drift. We caution that genetic drift may be an alternative mechanism (in addition to recombination hot-spots) that can lead to block-like patterns of LD. Our findings highlight the necessity of characterizing haplotype blocks in world-wide populations.     

Exploring residues crucial for nitrilase function by site directed mutagenesis to gain better insight into sequence-function relationships

Nitrilases represent a very important class of enzymes having an array of applications. In the present scenario, where the indepth information about nitrilases is limited, the present work is an attempt to shed light on the residues crucial for the nitrilase activity. The nitrilase sequences demonstrating varying degree of identity with P. putida nitrilase were explored. A stretch of residues, fairly conserved throughout the range of higher (96%) to lower (27%) sequence identity among different nitrilases was selected and investigated for the possible functional role in nitrilase enzyme system. Subsequently, the alanine substitution mutants (T48A, W49A, L50A, P51A, G52A, Y53A and P54A) were generated. Substitution of the rationally selected conserved residues altered the substrate recognition ability, catalysis and affected the substrate specificity but had very little impact on enantioselectivity and pattern of nitrile hydrolysis.     

The Fragilis interferon-inducible gene family of transmembrane proteins is associated with germ cell specification in mice

Background  

Specification of primordial germ cells in mice depends on instructive signalling events, which act first to confer germ cell competence on epiblast cells, and second, to impose a germ cell fate upon competent precursors. fragilis, an interferon-inducible gene coding for a transmembrane protein, is the first gene to be implicated in the acquisition of germ cell competence.     

Relationship between CD107a expression and cytotoxic activity

NK cells play important roles in innate immunity against tumors and infections of the host. Studies show that CD107a (LAMP-1) may be a marker for degranulation of NK and activated CD8⁺ T cells. In our study, the relationship between the expression of CD107a, cytokine secretion and cytotoxic activity in CD56⁺ NK, CD8⁺ T cells and lymphocytes has been determined after various stimuli. Effector cells from PBMCs of healthy subjects were isolated and K562 cell line was used as target of cytotoxicity. IL-2 stimulation resulted in a significant increase of CD107a expression in CD56⁺ NK, CD8⁺ T cells and lymphocytes. Increased expression of CD107a after IL-2 stimulation of NK cells was parallel to the increase of cytotoxicity. Our results suggest that CD107a expression may be a sensitive marker for the cytotoxic activity determination.