HSulf-2, an extracellular endoglucosamine-6-sulfatase, selectively mobilizes heparin-bound growth factors and chemokines: effects on VEGF, FGF-1, and SDF-1

Background  

Heparin/heparan sulfate (HS) proteoglycans are found in the extracellular matrix (ECM) and on the cell surface. A considerable body of evidence has established that heparin and heparan sulfate proteoglycans (HSPGs) interact with numerous protein ligands including fibroblast growth factors, vascular endothelial growth factor (VEGF), cytokines, and chemokines. These interactions are highly dependent upon the pattern of sulfation modifications within the glycosaminoglycan chains. We previously cloned a cDNA encoding a novel human endosulfatase, HSulf-2, which removes 6-O-sulfate groups on glucosamine from subregions of intact heparin. Here, we have employed both recombinant HSulf-2 and the native enzyme from conditioned medium of the MCF-7-breast carcinoma cell line. To determine whether HSulf-2 modulates the interactions between heparin-binding factors and heparin, we developed an ELISA, in which soluble factors were allowed to bind to immobilized heparin.     

Intermode energy transfer in vibrationally excited O3

The laser excited fluorescence method has been employed to determine the rate constants for vibrational relaxation of the O₃ (010), O₃ (100) and O₃ (001) levels at 298 K. The fluorescence observations from the O₃ (010) level provide direct measurements of the rate for intermode vibrational energy transfer from the coupled ν₁ and ν₃ modes to the ν₂ mode. The slowness of this process indicates the likelihood that the ν₁ and/or ν₃ modes (rather than the ν₂ mode) play a predominant role in the laser enhanced reaction between O₃² and NO at 298 K.     

The Adsorption of Gemini and Conventional Surfactants onto Some Soil Solids and the Removal of 2-Naphthol by the Soil Surfaces

The adsorption of two cationic gemini surfactants, [C(n)H(2n+1) N(+)(CH(3))(2)-CH(2)CH(2)](2).2Br(-), where n=12 and 14, on limestone, sand, and clay (Na-montmorillonite) from their aqueous solution in double-distilled water and the effect of this adsorption on the removal of 2-naphthol have been studied. Compared to those of conventional cationic surfactants with similar single hydrophilic and hydrophobic groups (C(n)H(2n+1)N(+)(CH(3))(3).Br(-), where n=12 and 14), the molar adsorptions of the gemini and the conventional surfactants on Na-montmorillonite are almost identical and very close to their cation exchange capacities. On sand and limestone, the molar adsorption of the cationic gemini surfactants is much larger than that of their corresponding conventional surfactants. Adsorption studies of the pollutants onto the three kinds of solids treated by either the gemini or the conventional surfactants show that the former are both more efficient and more effective at removing 2-naphthol from the aqueous phase. On all three soil solids, the addition of KBr increases the efficiency of the adsorption of both types of cationics and for most cases increases also the maximum amount adsorbed, but decreases slightly the efficiency of removal of 2-naphthol. On limestone, the anionic gemini adsorbs with one hydrophilic group oriented toward the Ca(2+) sites on the surface and its second hydrophilic group oriented toward the aqueous phase. The conventional anionic surfactant forms a double layer. The gemini anionic is more efficient and more effective than the conventional anionic in the removal of 2-naphathol from the aqueous phase. Both anionic conventional and gemini surfactants have no adsorption on sand. The adsorption mechanisms for all the surfactants on the three soil solid surfaces are discussed. Copyright 2001 Academic Press.     

Photoinduced formation of phosphido-bridged clusters derived from Ru3(CO)9(PPh2H)3. Crystal and molecular structure of Ru3(μ-H)(μ-PPh2)3(CO)7

The new complex Ru₃(CO)₉(PPh₂H)₃ (I) was prepared by the direct thermal reaction of Ru₃(CO)₁₂ with PPh₂ H and was spectroscopically characterized. Irradiation of I with λ ≥ 300 nm leads to the formation of Ru₂(μ-PPh₂)₂(CO)₆ (II) and three new phosphido-bridged complexes, Ru₃(μ-H)₂(μ-PPh₂)₂(CO)₈ (III), Ru₃(μ-H)₂(μ-PPh₂)₂(CO)₇(PPh₂H) (IV) and Ru₃(μ-H)(μ-PPh₂)₃(CO)₇ (V). These complexes have been characterized spectroscopically and Ru₃ (μ-H)(μ-PPh₂)₃(CO)₇ by a complete single crystal X-ray structure determination. It crystallizes in the space group P2₁/n with a 20.256(3), b 22.418(6), c 20.433(5) Å, β 112.64(2)°, V 8564(4) ų, and Z = 8. Diffraction data were collected on a Syntex P2₁ automated diffractometer using graphite-monochromatized Mo-K_α radiation, and the structure was refined to R_F 4.76% and R_wF 5.25% for the 8,847 independent reflections with F₀ > 6σ(F₀). The structure consists of a triangular array of Ru atoms with seven terminal carbonyl ligands, three bridging diphenylphosphido ligands which bridge each of the RuRu bonds, and the hydride ligand which bridges one RuRu bond. Complex IV was also shown to give V upon photolysis and is thus an intermediate in the photoinduced formation of V from I.     

Comparing search strategies for finding global optima on energy landscapes

We provide some tests of the convex global underestimator (CGU) algorithm, which aims to find global minima on funnel-shaped energy landscapes. We use two different potential functions—the reduced Lennard–Jones cluster potential, and the modified Sun protein folding potential, to compare the CGU algorithm with the simplest versions of the traditional trajectory-based search methods, simulated annealing (SA), and Monte Carlo (MC). For both potentials, the CGU reaches energies lower on the landscapes than both SA and MC, even when SA and MC are given the same number of starting points as in a full CGU run or when all methods are given the same amount of computer time. The CGU consistently finds the global minima of the Lennard–Jones potential for all cases with up to at least n=30 degrees of freedom. Finding the global or near-global minimum in the CGU method requires polynomial time [scaling between O(n³) and O(n⁴)], on average. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 1527–1532, 1999     

Aggregation kinetics and precipitation phenomena in poly(phenylisocyanide)

The preparation of N-phenyl-substituted poly(isocyanide) (N-ϕ-PIM) utilizing a Ni(II) catalyst in methanol yields a brown material having a number average molecular weight of about 2000. Analysis of this “as prepared” polymer indicates that a rigid rod structure is present in the derived solid. Dissolution of this “as prepared” N-ϕ-PIM in halocarbon solvents or THF apparently leads to unraveling of the helical polymer with subsequent aggregation and precipitation of materials that have different properties from the original. These processes have been investigated by NMR, GPC, and light-scattering techniques in THF and other solvents. UV spectroscopy has been utilized to follow the kinetics of the aggregation process in solution. X-ray diffraction (XRD) measurements have been employed to investigate the changes attendant with precipitation. An explanation of these observations is offered that implicates the uncoiling of the rigid rod helix as the most important step in defining subsequent physical and chemical properties of the ultimate amorphous polymer. © 1997 John Wiley & Sons, Inc.     

Ligand recognition by SH3 and WW domains: the role of N-alkylation in PPII helices.

SH3 and WW domains are involved in a variety of intracellular signaling pathways. Recent work has shed light on the mechanism whereby these signaling modules recognize prolines in polyproline ligands, which has implications in the design of ligands selectively targeting these interactions.     

SO(∀∃*) Sentences and Their Asymptotic Probabilities

We prove a 0‐1 law for the fragment of second order logic SO(∀∃*) over parametric classes of finite structures which allow only one unary atomic type. This completes the investigation of 0‐1 laws for fragments of second order logic defined in terms of first order quantifier prefixes over, e.g., simple graphs and tournaments. We also prove a low oscillation law, and establish the 0‐1 law for Σ¹₄(∀∃*) without any restriction on the number of unary types.