Isolation of a haemorrhagic protein toxin (SA-HT) from the Indian venomous butterfish (Scatophagus argus, Linn) sting extract

A haemorrhagic protein toxin (SA-HT) was isolated and purified from the spine extract of the Indian venomous butterfish, S. argus Linn, by two step ion exchange chromatography. The toxin was homogeneous in native and SDS-PAGE gel. SDS-molecular weight of the toxin was found to be 18.1 +/- 0.09 kDa. SA-HT produced severe haemorrhage on stomach wall but devoid of cutaneous haemorrhage. UV, EDTA, trypsin, protease, cyproheptadine, indomethacin, acetylsalicylic acid and BW755C treatment significantly antagonized the haemorrhagic activity of SA-HT. The toxin produced dose and time dependent oedema on mice hind paw, which was significantly encountered by cyproheptadine, indomethacin and BW755C. SA-HT increased capillary permeability on guinea pig dorsal flank. On isolated guineapig ileum, rat fundus and uterus, SA-HT produced slow contraction which was completely antagonised by prostaglandin blocker SC19220. On isolated rat duodenum, SA-HT produced slow relaxation. SA-HT significantly increased plasma plasmin, serum MDA level and decreased serum SOD level indicating the possible involvement of cyclooxygenase and lipooxygenase pathway.     

Two new end-to-end single dicyanamide bridged Cu(II) complexes with Schiff base ligands: Structural, electrochemical and magnetic properties

The synthesis, crystal structures and magnetic properties of two different copper(II) complexes of formula [Cu(L¹)(dca)]_n · nClO₄ (1) and [Cu(L²)]₂(dca)(ClO₄) (2) [L¹ = N,N-dimethylethylene-N′-(pyridine-2-carbaldiiminato), HL² = N,N-dimethylethylene-N′-salicylaldiiminato, dca = dicyanamide anion] are described. Spectroscopic and electrochemical properties have also been discussed. A one-dimensional chain structure with single, symmetrical, μ_1,5-dca bridges is found in compound 1. The copper atom in 1 has a square pyramidal geometry. A tridentate Schiff base ligand, having NNN donor sites, and one nitrogen atom from dca occupy the basal plane. N(18) of a neighbouring unit occupies the apical site. The Schiff base used in compound 2 is a tridentate anion with NNO donor sites, which changes the structure in a dinuclear unit of copper atoms bridged by single end-to-end dicyanamide ion. The environment around copper in 2 is square planar. Magnetic susceptibility measurements for 1 and 2 reveal the occurrence of weak antiferromagnetic interaction through the dca ligand.     

Real-time monitoring of RAG-catalyzed DNA cleavage unveils dynamic changes in coding end association with the coding end complex

During V(D)J recombination, the RAG1/2 recombinase is thought to play an active role in transferring newly excised recombination ends from the RAG post-cleavage complex (PCC) to the non-homologous end joining (NHEJ) machinery to promote appropriate antigen receptor gene assembly. However, this transfer mechanism is poorly understood, partly because of the technical difficulty in revealing weak association of coding ends (CEs) with one of the PCCs, coding end complex (CEC). Using fluorescence resonance energy transfer (FRET) and anisotropy measurement, we present here real-time monitoring of the RAG1/2-catalyzed cleavage reaction, and provide unequivocal evidence that CEs are retained within the CEC in the presence of Mg(2+). By examining the dynamic fluorescence changes during the cleavage reaction, we compared the stability of CEC assembled with core RAG1 paired with full-length RAG2, core RAG2 or a frameshift RAG2 mutant that was speculated to destabilize the PCC, leading to increased aberrant joining. While the latter two CECs exhibit similar stability, the full-length RAG2 renders a less stable CEC unless H3K4me3 peptides are added. Interestingly, the RAG2 mutant appears to modulate the structure of the RAG-12RSS pre-cleavage complex. Thus, the fluorescence-based detection offers a sensitive, quantitative and continuous assessment of pre-cleavage complex assembly and CEC stability.     

Inheritance of dermatoglyphic asymmetry in 500 Indian pedigrees: complex segregation analysis

The major aim of this study is to determine the mode of inheritance of asymmetry of quantitative dermatoglyphic traits based on principal factors through the application of complex segregation (genetic model fitting) analyses on a large ethnically homogeneous sample of 500 Indian pedigrees (2435 individuals) of two generations. By segregation analysis of the traits- PC1_FA both Mendelian and Environmental models were rejected (< 0.001) with the General model, i.e. that despite presence of significant inheritance (rejection of Environmental model), the nature of inheritance is more complex, than Mendelian one. Although a little genetic effect was observed due to familial correlations on asymmetry traits, no evidence was found of major gene contribution to be involved, but this does not contradict the notion postulated by several earlier authors that asymmetry (fluctuating) provides a measure of developmental instability in human.     

Antitumor potential of Castanopsis indica (Roxb. ex Lindl.) A. DC. leaf extract against Ehrlich's ascites carcinoma cell

Methanol extract of C. indica (MECI) leaves showed direct cytotoxicity on Ehrlich ascites carcinoma (EAC) cell in a dose dependant manner and there was significant decrease in the tumor volume, viable cell count, tumor weight and elevated the life span of EAC tumor bearing mice. Hematological profile and biochemical estimations were significantly restored to normal levels in MECI treated as compared to EAC control mice. MECI treatment significantly modulated the tissue antioxidant assay parameters as compared to the EAC control mice. The results revealed that MECI possesses significant dose dependent antitumor potential which may be due to its cytotoxicity and antioxidant properties.