Interaction of nitrobenzoxadiazole derivatives of piperazine and aniline with bovine serum albumine in silico and in vitro

Albumin is a globular protein of plasma of mammalian blood participating in transport of hydrophobic metabolites and drugs. Thus, studies devoted to its binding are valuable as a part of evaluation of new potential drugs or fluorescent probes for in vivo usage. Here we describe results concerning synthesis and bovine serum albumin binding assay both in silico (docking) and in vitro (spectrophotometric and spectrofluorimetric titrations) for four new 7-nitrobenzoxadiazol-4-yl (NBD) derivatives of aniline and piperazine. Experimental dissociation constant for NBD-ethynylaniline 4 was calculated to be about 10 µmol/L.

Bence-Jones Protein, Rat IGG, H.R.P, Alkaline Phosphatase, Bovine Serum Albumine used as Antigens in the Immune Response of the Sea Star.

Immunocompetent cells were described in the sea star Asterina gibbosa: they recognize specifically various antigens. In the present work, Asterina gibbosa were immunized with Bence-Jones protein, other ones with Rat IGG, at last certain with H.RP (Horse-radish Peroxydase) and the last ones with Alkaline Phosphatase: a crossed immune reaction occurs between Rat IGG and B.J protein, but not between B.J and H.R.P not between Rat IGG and H.R.P and not between Alkaline Phosphatase and B.J, not between Alkaline Phosphatase and Rat IGG, used as antigens.

The occurence of a nitrate reductase inactivating factor in extracts of Spirodela polyrrhiza

NADH-nitrate reductase (NR) had a low activity immediately after extraction from 14 day-old cultures of <em>Spirodela polyrrhiza</em> with the basic extraction solution (50 mM K-phosphate buffer, pH 7.5, 5 mM cysteine and 3 mM EDTA) whereas nitrite reductase (NiR) activity in the same extract was very high. Increasing the EDTA or cysteine concentration or replacing cysteine by dithiothreitol had no effect on the level of NR activity. The addition of 3% bovine serum albumine (BSA) and 0.4 mM phenylmethyl sulfonyfluoride (PMSF) or 3% BSA and 1.5% polyvinylpolypyrrolidone (PVPP) to the extraction solution greatly increased the NR activity. The enzyme activity increased 40 times in the presence of 1.5% PVPP with 3% BSA and 0.4 mM PMSF. The highest NR activity (over 100-fold) was found in the presence of 3% caseine. The probable nature of the factor inactivating nitrate reductase in <em>S. polyrrhiza</em> extracts is discussed.

The simultaneous exposition of galactose and mannose-specific receptors on rat liver macrophages is developmentally regulated

We studied the simultaneous binding of galactose and mannose-exposing ligands in sinusoidal rat liver cells during development and aging. The galactose-specific receptors were visualized using 17 nm diameter colloidal gold particles coupled with Lactosylated bovine serum albumine (LacBSA), while mannose-specific receptors were localized by means of 5 nm diameter particles adsorbed with mannan. We observed the presence of four different classes of Kupffer cells in relation to the ligands bound. The percentage of each group of Kupffer cells varied in relation to the age of the subject from which the sample was taken. There were few double-labelled cells in the livers from newborn rats, with numbers increasing with age to adulthood, and decreasing again in the older animals. Cells without labelling were in the majority after birth, but they decreased in number up to adulthood and increased again during subsequent aging. The numbers of single-labelled cells did not change significantly during liver maturation. We hypothesize that the exposition of galactose and mannose-specific receptorial systems is regulated by developmental conditions.