A hybrid protein of urokinase growth-factor domain and plasminogen-activator inhibitor type 2 inhibits urokinase activity and binds to the urokinase receptor.

The binding of urokinase-type plasminogen activator (uPA) to its specific cell-surface receptor (uPAR) localises the proteolytic cascade initiated by uPA to the pericellular environment. Inhibition of uPA activity or prevention of uPA binding to uPAR might have a beneficial effect on disease states wherein this activity is deregulated, e.g. cancer and some inflammatory diseases. To this end, a bifunctional hybrid molecule consisting of the uPAR-binding growth-factor domain of uPA (amino acids 1-47; GFuPA) at the N-terminus of plasminogen-activator inhibitor type 2 (PAI-2) was produced in Saccharomyces cerevisiae. The purified protein inhibited uPA with kinetics similar to placental or recombinant PAI-2 and was also found to bind to U937 cells and to FL amnion cells. GFuPA-PAI-2 competed with uPA, the N-terminal fragment of uPA and a proteolytic fragment of uPA (amino acids 4-43) in cell binding experiments, indicating that the molecule bound to the cells via uPAR. Hence, both the uPA-inhibitory and uPAR-binding domains of the hybrid molecule were functional, demonstrating the feasibility of the novel concept of introducing an unrelated, functional domain onto a member of the serine-protease-inhibitor superfamily.     

Platinum complexes of p- and m-aminobenzamidine. Synthesis, characterization, and cytotoxic activity.

Four platinum(II) aminobenzamidine complexes have been prepared and characterized by IR and 1H and 13C NMR spectroscopy, and tested for their ability to interact with the nicked and closed circular forms of the pUC8 plasmid DNA. The results show that the complexes of formula [Pt(LH)2Cl2]2X have a cis- geometry with an amino-Pt bonding, where L is either p- or m-aminobenzamidine and where 2X is 2Cl- or PtCl4(2-). It was observed that these complexes significantly alter the electrophoretic mobility of nicked and closed circular forms of DNA and that the alteration in electrophoretic mobility due to Pt(II)-p-aminobenzamidine binding is higher than that due to Pt(II)-m-aminobenzamidine. No difference in mobility was observed whether the DNA interacted with complexes having as counteranion Cl- or PtCl4(2-). The synthesized compounds were, in addition, assayed for antitumor activity in vitro against colon (CX-1), lung (LX-1), and mammary (MX-1) human tumor cells. The results show that these complexes inhibited the multiplication of the tumor cells and that they show higher specificity for lung cells.     

Dynamics and reactivity of HbXL99 alpha. A cross-linked hemoglobin derivative

Resonance Raman spectroscopy, transient absorption, and fluroescence techniques have been employed to investigate the structure and dynamics of the alpha-cross-linked hemoglobin derivative, HbXL99 alpha. The resonance Raman spectra of the deoxy form of HbXL99 alpha are identical to those of native NbA (VFe-His approximately 222 cm-1), which exhibit a T-state (low affinity) structure regardless of solvent conditions. The resonance Raman spectra of the transient heme photoproduct resulting from CO photolysis from HbXL99 alpha appear to have structures intermediate between deoxy-T and ligand-bound R structures (VFe-His approximately 222 cm-1). Time-resolved resonance Raman data of HbXL99 alpha-CO show that complete CO recombination occurs after approximately 5 ms, with only a small amount of the CO-bound species reforming within approximately 200 ns (geminate recombination). Transient absorption spectra of HbXL99 alpha-O2 indicate that the extent of sub-nanosecond geminate recombination of O2 is also reduced in the cross-linked derivative relative to native HbA. The decrease in tryptophan fluorescence of HbXL99 alpha upon oxygenation further indicates that tertiary structural changes at the alpha 1-beta 2 interface upon ligation are apparently reduced, but not eliminated in the cross-linked derivative relative to HbA.     

Postnatal Changes in the Activity Ratio of Specific and Nonspecific Cholinesterases from Neuronal Perikarya

Abstract: A soluble fraction from rat brain neuronal perikarya was shown to contain both the specific and nonspecific forms of the enzyme acetylcholines-terase (EC's 3.1.1.7. and 3.1.1.8., respectively). The ratio of the enzyme activities varied along the course of brain development: the nonspecific form being predominant from 1 to 15 days of age and the specific one showing the pattern of rising activity from day 15 onward. We suggest a possible relationship between this changing in cholinesterase activities and the establishment of synapses within the rat cerebral cortex.     

gA and gB glycoproteins of herpes simplex virus type 1: two forms of a single polypeptide.

Utilizing a combination of preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sodium dodecyl sulfate-hydroxylapatite column chromatography, we have separated and purified the gA and gB glycoproteins of the major virus-specific glycoprotein region from herpes simplex virus type 1-infected cells. By using purified antigen preparations, antisera specific to each of these glycoproteins were produced. Immunoprecipitation from detergent extracts of infected cells and radioimmune precipitation of the purified antigens have shown that the anti-gA and anti-gB sera each recognize both the gA and the gB glycoproteins. The anti-gA serum was also shown to neutralize virus despite the presence of only minute quantities of the gA glycoprotein in virions. Pulse-chase studies have indicated that the gA and gB glycoproteins are synthesized from a common precursor polypeptide. Together, these data demonstrate that the gA and gB glycoproteins of herpes simplex virus type 1 are antigenically similar but not identical and probably represent two different forms of the same polypeptide which differ in their degree of glycosylation.     

Accumulation of polychlorinated biphenyls in turbot(Scophthalmus maximus) from seawater sediments and food

Juvenile turbot,Scophthalmus maximus (L.), were exposed to 0.58 μg 1⁻¹ Aroclor 1254 in seawater, to sediments containing 100, 60 and 1 ppm or fed with cockle containing 20 ppm PCB (polychlorinated biphenyls). Concentration factors for liver and muscle were 10⁴ and 10³, respectively, for uptake of PCB from seawater. Contamination of muscle was similar to that of sediments containing 1 and 60 ppm PCB to which turbot were exposed, but less than the 20 ppm in their experimental diet. Contamination of flatfish in the North Sea area is compared with the levels of PCB in the flounder,Platichthys flesus (L.), in the River Thames and predictable values for uptake of PCB from different pathways discussed.     

DNA-negative temperature-sensitive mutants of herpes simplex virus type 1: patterns of viral DNA synthesis after temperature shift-up.

Temperature-sensitive mutants of herpes simplex virus type 1 belonging to four DNA- complementation groups exhibited two distinct patterns of viral DNA synthesis after shift-up to the nonpermissive temperature. In cultures infected with mutants belonging to complementation groups A, C, and D, little or no viral DNA was synthesized after shift-up. In cultures infected with a mutant in complementation group B, nearly normal amounts of viral DNA were synthesized after shift-up.