Fast Change Detection

Automated detection of changes in a sequence of images captured under fixed background and steady light condition is an often required operation having widespread application. Possible application areas can be as diverse as from military to atmospheric science, from medicine to video surveillance, etc. There are many approaches to the problem of detecting changes; the more reliable one tries to make these more complex and computationally expensive these become, requiring sophisticated algorithms and specialised hardware. However, often one needs to use simple and computationally cheap procedures to be used with cots hardware when the problem scenario has static features with transient change in features associated to some small part of the image or field of view. A super-pixel-based change detection algorithm has been descried here that is basically a modification of the image differencing technique. The procedure has been seen to detect even a small transient change in intensity at a frame rate of as high as fifty frames per second using cots hardware.Defence Science Journal, 2011, 61(1), pp.51-56, DOI:http://dx.doi.org/10.14429/dsj.61.47

Anion-induced increases in the affinity of colcemid binding to tubulin

Colcemid binds tubulin rapidly and reversibly in contrast to colchicine which binds tubulin relatively slowly and essentially irreversibly. At 37° C the association rate constant for colcemid binding is 1.88 × 106 M-1 h-1, about 10 times higher than that for colchicine; this is reflected in the activation energies for binding which are 51.4 kJ/mol for colcemid and 84.8 kJ/mol for colchicine. Scatchard analysis indicates two binding sites on tubulin having different affinities for colcemid. The high-affinity site (Ka= 0.7 × 105 M-1 at 37° C) is sensitive to temperature and binds both colchicine and colcemid and hence they are mutually competitive inhibitors. The low-affinity site (Kb= 1.2 × 104 M-1) is rather insensitive to temperature and binds only colcemid. Like colchicine, 0.6 mol of colcemid are bound/mol of tubulin dimer (at the high-affinity site) and the reaction is entropy driven (163 J K-1 mol-1). Similar to colchicine, colcemid binding to tubulin is stimulated by certain anions (viz. sulfate and tartrate) but by a different mechanism. Colcemid binding affinity at the lower-affinity site of tubulin is increased in the presence of ammonium sulfate. Interestingly, the lower-affinity site on tubulin for colcemid, even when converted to higher affinity in presence of ammonium sulfate, is not recognized by colchicine. We conclude that tubulin possesses two binding sites, one of which specifically recognized the groups present on the B-ring of colchicine molecule and is effected by the ammonium sulfate, whereas the higher-affinity site, which could accommodate both colchicine and colcemid, possibly recognized the A and C ring of colchicine

Functional and Structural Analyses of CYP1B1 Variants Linked to Congenital and Adult-Onset Glaucoma to Investigate the Molecular Basis of These Diseases

Glaucoma, the leading cause of irreversible blindness, appears in various forms. Mutations in CYP1B1 result in primary congenital glaucoma (PCG) by an autosomal recessive mode of inheritance while it acts as a modifier locus for primary open angle glaucoma (POAG). We investigated the molecular basis of the variable phenotypes resulting from the defects in CYP1B1 by using subclones of 23 CYP1B1 mutants reported in glaucoma patients, in a cell based system by measuring the dual activity of the enzyme to metabolize both retinol and 17β-estradiol. Most variants linked to POAG showed low steroid metabolism while null or very high retinol metabolism was observed in variants identified in PCG. We examined the translational turnover rates of mutant proteins after the addition of cycloheximide and observed that the levels of enzyme activity mostly corroborated the translational turnover rate. We performed extensive normal mode analysis and molecular-dynamics-simulationsbased structural analyses and observed significant variation of fluctuation in certain segmental parts of the mutant proteins, especially at the B-C and F-G loops, which were previously shown to affect the dynamic behavior and ligand entry/exit properties of the cytochrome P450 family of proteins. Our molecular study corroborates the structural analysis,and suggests that the pathologic state of the carrier of CYP1B1 mutations is determined by the allelic state of the gene. To our knowledge, this is the first attempt to dissect biological activities of CYP1B1 for correlation with congenital and adult onset glaucomas

SLC45A2 (solute carrier family 45 member 2)

SLC45A2 gene, having a chromosomal location 5p13.2, encodes a membrane associated transporter protein (MATP). MATP is a transmembrane protein. It is present in the melanosomal membrane in the melanocytes. It maintains the osmotic potential by regulating the pH of the melanosomal lumen. Defects in the SLC45A2 gene causes oculocutaneous albinism type IV; OCA I

SLC24A5 (solute carrier family 24 (sodium/potassium/calcium exchanger), member 5)

SLC24A5 is a member of the potassium-dependent sodium/calcium exchanger family and encodes an intracellular membrane protein. Sequence variations in this gene have been associated with differences in skin pigmentation, and the defective protein leads to Oculocutaneous albinism type VI, OCA6

Oculocutaneous Albinism

Review on Oculocutaneous Albinis