Curcumin inhibits nitrite-induced methemoglobin formation.

Curcumin protects hemoglobin from nitrite-induced oxidation to methemoglobin. The protection is not observed when curcumin is added after the autocatalytic stage of the oxidation of hemoglobin by nitrite. The ability of curcumin to scavenge superoxide may be responsible since superoxide is implicated in promoting the autocatalytic stage of oxidation of hemoglobin by nitrite.     

Segmental gradients specifying polarity and pattern in the wax moth,Galleria mellonella: The posterior margin as the source of a diffusible morphogen

The basis for our experiments was a report by Piepho and Hintze-Podufal 1971 about the ability of the segmental posterior margin (PM) to induce alteration of polarity and pattern in abdominal segments of the wax moth Galleria mellonella. We planned to determine (1) whether the occurrence of ectopic PM on the host segment is due to integration of donor PM cells into the host epidermis and, if not, (2) what is the communication process leading to these developmental changes. Various intersegmental implantation and grafting experiments were carried out in late last instar larvae and the response of the host cells was determined by noting changes in orientation and morphology of the scales and sockets in the adult segment. A piece of the 5th PM implanted into the middle of the 7th segment near the surface, with the implant and host epidermis facing each other, induced overlying host cells to form 7th PM-type scales. This pattern transformation is not due to integration of donor PM cells into the host epidermis since grafted PM cells always retain their segmental identity. The implanted PM may cause reorientation of overlying host scales in a centripetal manner with or without accompanying pattern change. Both polarity and pattern changes can occur even when a nucleopore filter (0.03 μm) or a thin slice of agar is interposed between implant and host epidermis. From these and two cases of cell-free induction, we conclude that the PM is probably the source of a diffusible morphogen which influences polarity and pattern. The morphogen appears to be produced only during early stages of the larval-pupal molt and the host cells are sensitive to the factor only during critical periods in morphogenesis. The segmental anterior margin (AM) has an influence on polarity but appears to exert this effect only through cell contact. Our results are discussed in relation to current models of polarity and pattern regulation in the insect integument.     

Novel post-translational modifications of Smad2 identified by mass spectrometry

Smad2 is a crucial component of transforming growth factor-β (TGFβ) signaling, and is involved in the regulation of cell proliferation, death and differentiation. Phosphorylation, ubiquitylation and acetylation of Smad2 have been found to regulate its activity. We used mass spectrometry to search for novel post-translational modifications (PTMs) of Smad2. Peptide mass fingerprinting (PMF) indicated that Smad2 can be acetylated, methylated, citrullinated, phosphorylated and palmitoylated. Sequencing of selected peptides validated methylation at Gly122 and hydroxylation at Trp18 of Smad2. We also observed a novel, so far unidentified modification at Tyr128 and Tyr151. Our observations open for further exploration of biological importance of the detected PTMs. Electronic Supplementary Material  Supplementary material is available for this article at and is accessible for authorized users.     

Effect of oxidizing adulterants on human urinary steroid profiles

Steroid profiling is the most versatile and informative technique adapted by doping control laboratories for detection of steroid abuse. The absolute concentrations and ratios of endogenous steroids including testosterone, epitestosterone, androsterone, etiocholanolone, 5α-androstane-3α,17β-diol and 5β-androstane-3α,17β-diol constitute the significant characteristics of a steroid profile. In the present study we report the influence of various oxidizing adulterants on the steroid profile of human urine. Gas chromatography–mass spectrometry analysis was carried out to develop the steroid profile of human male and female urine. Oxidants potassium nitrite, sodium hypochlorite, potassium permanganate, cerium ammonium nitrate, sodium metaperiodate, pyridinium chlorochromate, potassium dichromate and potassium perchlorate were reacted with urine at various concentrations and conditions and the effect of these oxidants on the steroid profile were analyzed. Most of the oxidizing chemicals led to significant changes in endogenous steroid profile parameters which were considered stable under normal conditions. These oxidizing chemicals can cause serious problems regarding the interpretation of steroid profiles and have the potential to act as masking agents that can complicate or prevent the detection of the steroid abuse.     

Dynamics of amino acid residues in globular proteins

The dynamic differential equation model developed and tested for bovine pancreatic trypsin inhibitor and tuna ferrocytochrome c in Ponnuswamy, P.K. & Bhaskaran, R. (Int. J. Peptide Protein Res. 24, 168-179, 1984) is extended for 17 more protein crystals in this work. Average displacements are computed for 20 amino acid residues observed in 19 proteins. Detailed information on the dynamic behaviour of the individual proteins and individual residues is presented. The effect of atomic packing on the fluctuations of the amino acid residues in alpha-chymotrypsin is illustrated. A number of general points on the dynamic characteristics of globular protein molecules are presented.