Studies on components 1' (modified monomer) and 2 (dimer) formed during heat-treatment of bovine serum albumin

When the solution of bovine serum albumin at pH 9 is incubated at 65 °C, new components 1' (modified monomer), 2 (dimer) and 3 (probably trimer) are formed. The isoelectric focusing indicated that the isoelectric points of components 1', 2 and 3 were pH 5.9.The hydrogen ion titration curve for the native albumin had well known abnormal steepness at pH near 4, but that for component 1' had no abnormal steepness. The titration curve for component 1' located right side of that for the native albumin.Circular dichroism measurements indicated that some unfolding occurred, when the native albumin was changed to component 1'. The contents of-helix were 74 and 52 % for the native albumin and for component 1', respectively. The contents of -structure were 19 and 23 % for the native albumin and for component 1', respectively. The wavelength of maximum intensity of tryptophan fluorescence shifted to lower wavelength, when the native albumin was changed to component 1'. This suggests that tryptophan residue(s) is transferred to a more hydrophobic environment.The hydrogen ion titration curves, circular dichroism and fluorescence measurements, all supported the possibility that the component 2 is formed by the dimerization of component 1'. Further, it has been found that component 2' (dimer impurity in commercial bovine serum albumin preparations) is formed by the direct dimerization of native bovine serum albumin without conformational change.     

Expression of Discoidin Domain Receptor 2 (DDR2) in the developing heart.

Interactions between cells and the surrounding extracellular matrix are important for a number of developmental events. In the heart, cardiac fibroblasts produce the majority of extracellular matrix proteins, particularly collagen types I and III. Cells originating from the proepicardial organ migrate over the surface of the heart, invade the underlying myocardium and ultimately give rise to smooth muscle cells, fibroblasts, and coronary endothelium. Although integrin expression in the developing heart has been well characterized, the expression of Discoidin Domain Receptor 2 (DDR2) remains to be defined. Using confocal microscopy, the expression of DDR2 was examined at several points during cardiac development. Initially, DDR2 expression was detected on the epicardial surface of the heart and on endothelial and mesenchymal cells within the cardiac cushions. As development progressed, DDR2 expression increased at localized regions in the apex and atrioventricular sulcus, although this expression decreased from epicardial to endocardial surface. Eventually, DDR2 expression spanned the myocardial free wall and was detected within the septum. Not until postnatal development was DDR2 expression detected uniformly throughout the myocardium and this distribution was maintained in the adult heart. In summary, the data presented demonstrate that the distribution of DDR2-positive cells changes within the heart during development.     

The 1 (2)A(1), 1 (2)B(2), and 1 (2)A(2) states of the SO(2) (+) ion studied using multiconfiguration second-order perturbation theory

The 1 (2)A(1), 1 (2)B(2), and 1 (2)A(2) electronic states of the SO(2) (+) ion have been studied using multiconfiguration second-order perturbation theory (CASPT2) and two contracted atomic natural orbital basis sets, S[6s4p3d1f]/O[5s3p2d1f] (ANO-L) and S[4s3p2d]/O[3s2p1d] (ANO-S), and the three states were considered to correspond to the observed X, B, and A states, respectively, in the previous experimental and theoretical studies. Based on the CASPT2/ANO-L adiabatic excitation energy calculations, the X, A, and B states of SO(2) (+) are assigned to 1 (2)A(1), 1 (2)B(2), and 1 (2)A(2), respectively, and our assignments of the A and B states are contrary to the previous assignments (A to (2)A(2) and B to (2)B(2)). The CASPT2/ANO-L energetic calculations also indicate that the 1 (2)A(1), 1 (2)B(2), and 1 (2)A(2) states are, respectively, the ground, first excited, and second excited states at the ground-state (1 (2)A(1)) geometry of the ion and at the geometry of the ground-state SO(2) molecule. Based on the CASPT2/ANO-L results for the geometries, we realize that the experimental geometries (determined by assuming the bond lengths to be the same as the neutral ground state of SO(2)) were not accurate. The CASPT2/ANO-S calculations for the potential energy curves as functions of the OSO angle confirm that the 1 (2)B(2) and 1 (2)A(2) states are the results of the Renner-Teller effect in the degenerate (2)Pi(g) state at the linear geometry, and it is clearly shown that the 1 (2)B(2) curve, as the lower component of the Renner splitting, lies below the 1 (2)A(2) curve. The UB3LYP/cc-pVTZ adiabatic excitation energy calculations support the assignments (A to (2)B(2) and B to (2)A(2)) based on the CASPT2/ANO-L calculations.     

M1 transition probabilities between fine structure components2L J (L ≥ 1)

Spontaneous emission transition probabilities of the magnetic dipole transitions between states of ground state configurations consisting of onenl electron (or a hole) outside a closed shell have been calculated by using relativistic terms of order α² Z ² and using hydrogenic orbitals to calculate the required overlap integrals. The line strengths calculated for the Boron and Fluorine isoelectronic sequences are in excellent agreement with the calculations involving Dirac wavefunctions for all ions uptoZ=60. The maximum difference at the highest value ofZ=92 is about 6%. Our calculated lifetimes for the state 2p ^{5 2} P _1/2 for Fluorine-like Mg IV and Fe XVIII are 5.03 s and 51.7 µs respectively which are in excellent accord with corresponding values 5.00 s and 51.0 µs calculated by using sophisticated configuration interaction wavefunctions within the Breit-Pauli approximation. Our calculated value of lifetime for Thalium-like Pb II is 40.0 ms which is in good accord with the experimental value of 41.2 ms. New results are presented for the highly ionized ions in the Al-like and Cl-like isoelectronic sequences. The present analysis can be exploited for all the ions in the isoelectronic sequences of elements of groups III A, III B VII A of the periodic table.     

LYRM1, a gene that promotes proliferation and inhibits apoptosis during heart development

Congenital heart disease (CHD) is the most common type of birth defect, but its underlying molecular mechanisms remain unidentified. Previous studies determined that Homo sapiens LYR motif containing 1 (LYRM1) is a novel nucleoprotein expressed at the highest level in adipose tissue and in high levels in heart tissue. The LYRM1 gene may play an important role in the development of the human heart. This study was designed to identify the biological characteristics of the LYRM1 gene in heart development. On the basis of expression-specific differentiation markers identified with quantitative real-time RT-PCR and the morphology of LYRM1-overexpressing cells during differentiation, ectopic expression was not found to significantly affect differentiation of P19 cells into cardiomyocytes. MTT assays and cell cycle analysis showed that LYRM1 dramatically increases the proliferation of P19 cells. Furthermore, data from annexin V-FITC binding and caspase-3 activity revealed that LYRM1 can inhibit the apoptosis of P19 cells. Our data suggest that LYRM1 might have the potential to modulate cell growth, apoptosis, and heart development.     

Synthesis and properties of 1-(2-bromoethyl)-, 1-(2-alkoxyethyl)- and 1-(2-dialkylaminoethyl)2-alkylpyrroles

The reaction of 3-chloropropenyl alkyl ketones or 2,3-dichloropropyl alkyl ketones with 2-substituted ethylamine derivatives leads to the formation of the hitherto unknown 1-(2-R-ethyl)-2-alkylpyrroles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1047–1049, August, 1990.     

Ultraviolet photoinactivation studies on hybrid viruses obtained by the cross-reconstitution of the protein and RNA components of U(1) and U(2) strains of TMV

The sensitivities of U(1) and U(2) TMV strains to inactivation by ultraviolet light at 253.7 nm were compared with those of hybrid viruses obtained by reconstituting the protein of either native strain with the RNA of the other. In each case, the hybrid virus was found to be virtually identical in sensitivity to the native strain which supplied the protein coat, indicating that the relative sensitivities of the two native strains to ultraviolet light are solely a function of their respective protein coats. Amino acid analysis of the U (2) protein reveals about thirteen or fourteen amino acid replacements compared with the U (1) strain, which is in agreement with earlier studies indicating that there are considerable differences in the protein subunits of the two proteins. Some of the ways in which the observed differences in proteins of the two strains may determine their respective ultraviolet sensitivities are discussed.     

Low-temperature magnetic behavior of perovskite compounds PbFe(1/2)Ta(1/2)O3 and PbFe(1/2)Nb(1/2)O3

The isostructural perovskite compounds PbFe(1/2)Ta(1/2)O3 and PbFe(1/2)Nb(1/2)O3 have been known for long time, and they are part of the important class of materials called multiferroic, where ferroelasticity, ferroelectricity, and ferromagnetism coexist. In the literature regarding PbFe(1/2)Ta(1/2)O3 and PbFe(1/2)Nb(1/2)O3, an "anomaly" of their low-temperature magnetic behavior has not always been reported. Moreover, both the origin of this behavior, and the cause for which it was not always observed, were never completely explained. In this paper, the magnetic behavior of the two compounds at low temperature has been extensively studied and explained as the occurring of a spin-glasslike transition.     

Inner-valence photoionization of O((1)D): experimental evidence for the 2s(2)2p(4)((1)D)-->2s(1)2p(5)((1)P) transition

Photoionization and autoionization of electronically excited atomic oxygen O((1)D) are investigated in the energy range between 12 and 26 eV using tunable laser-produced plasma radiation in combination with time-of-flight mass spectrometry. A broad, asymmetric, and intense feature is observed that is peaking at 20.53+/-0.05 eV. It is assigned to the 2s(2)2p(4)((1)D)-->2s(1)2p(5)((1)P) transition, which subsequently autoionizes by a Coster-Kronig transition, as predicted by the previous theoretical work [K. L. Bell et al., J. Phys. B 22, 3197 (1989)]. Specifically, the energy of the unperturbed transition occurs at 20.35+/-0.07 eV. Its shape is described by a Fano profile revealing a q parameter of 4.25+/-0.8 and a width of gamma=2.2+/-0.15 eV. Absolute photoionization cross section sigma is derived, yielding sigma=22.5+/-2.3 Mb at the maximum of the resonance. In addition, weak contributions to the O((1)D) yield from dissociative ionization originating from molecular singlet oxygen [O(2)((1)Delta(g))] are identified as well. Possible applications of the 2s(2)2p(4)((1)D)-->2s(1)2p(5)((1)P) transition as a state-selective and sensitive probe of excited oxygen in combination with photoionization mass spectrometry are briefly discussed.     

Characterization of low molecular weight components of [(ViMe2SiO1/2)x(PhSiO3/2)y(SiO4/2)z], [(ViMe2SiO1/2)x(SiO4/2)y], and [(SiO4/2)x(HO1/2)y(tBuO1/2)z] silsesquioxanes by electrospray ionization fourier transform mass spectrometry (ESI-FTMS)

This paper describes the characterization of low molecular weight components of four materials using electrospray ionization Fourier transform mass spectrometry (ESI-FTMS). The materials in the current study are [(ViMe₂SiO_1/2)_x(PhSiO_3/2)_y(SiO_4/2)_z] (MTQ), [(ViMe₂SiO_1/2)_x(SiO_4/2)_y] (MQ), and [(SiO_4/2)_x(HO_1/2)_y(^tBuO_1/2)_z] (Q) silsesquioxanes. Accurate mass measurements coupled with knowledge of resin chemistry afforded siloxane composition determination that was used to propose specific structures for the oligomers. Branched or linear (T_nQ_mM_n+2m+2), and monocyclic (T_nQ_mM_n+2m) structures are predominant structures for the low molecular weight species in MTQ. For MQ and Q, more condensed structures, such as partially opened cage structures (Q_mM_2m?6 and Q_mM_2m?8), were identified. The differences between MQ, Q, and MTQ are likely attributed to differences in intrinsic structure and reactivity of T and Q building blocks. The structural information obtained for these oligomeric species will ultimately provide a better understanding of new resin materials and their associated physical properties.     

Beta-Amyloid (Aβ1-42) Increases the Expression of NKCC1 in the Mouse Hippocampus

Alzheimer’s disease (AD) is a neurodegenerative disorder with an increasing need for developing disease-modifying treatments as current therapies only provide marginal symptomatic relief. Recent evidence suggests the γ-aminobutyric acid (GABA) neurotransmitter system undergoes remodeling in AD, disrupting the excitatory/inhibitory (E/I) balance in the brain. Altered expression levels of K-Cl-2 (KCC2) and N-K-Cl-1 (NKCC1), which are cation–chloride cotransporters (CCCs), have been implicated in disrupting GABAergic activity by regulating GABA_A receptor signaling polarity in several neurological disorders, but these have not yet been explored in AD. NKCC1 and KCC2 regulate intracellular chloride [Cl⁻]_i by accumulating and extruding Cl⁻, respectively. Increased NKCC1 expression in mature neurons has been reported in these disease conditions, and bumetanide, an NKCC1 inhibitor, is suggested to show potential therapeutic benefits. This study used primary mouse hippocampal neurons to explore if KCC2 and NKCC1 expression levels are altered following beta-amyloid (Aβ_1-42) treatment and the potential neuroprotective effects of bumetanide. KCC2 and NKCC1 expression levels were also examined in 18-months-old male C57BL/6 mice following bilateral hippocampal Aβ_1-42 stereotaxic injection. No change in KCC2 and NKCC1 expression levels were observed in mouse hippocampal neurons treated with 1 nM Aβ_1-42, but NKCC1 expression increased 30-days post-Aβ_1-42-injection in the CA1 region of the mouse hippocampus. Primary mouse hippocampal cultures were treated with 1 nM Aβ_1-42 alone or with various concentrations of bumetanide (1 µM, 10 µM, 100 µM, 1 mM) to investigate the effect of the drug on cell viability. Aβ_1-42 produced 53.1 ± 1.4% cell death after 5 days, and the addition of bumetanide did not reduce this. However, the drug at all concentrations significantly reduced cell viability, suggesting bumetanide is highly neurotoxic. In summary, these results suggest that chronic exposure to Aβ_1-42 alters the balance of KCC2 and NKCC1 expression in a region-and layer-specific manner in mouse hippocampal tissue; therefore, this process most likely contributes to altered hippocampal E/I balance in this model. Furthermore, bumetanide induces hippocampal neurotoxicity, thus questioning its suitability for AD therapy. Further investigations are required to examine the effects of Aβ_1-42 on KCC2 and NKCC1 expression and whether targeting CCCs might offer a therapeutic approach for AD.     

Observation and analysis of the 2g(1D) ion-pair state of I2: the g/u mixing between the 1u(1D) and 2g(1D) states

We report the analysis of the 2g(1D) ion-pair state of I2 by perturbation-facilitated optical-optical double resonance. The present study began with the observation of the 2g(1D)-A' 3Pi(2u) emission at around 230 nm during the analysis of the ultraviolet emissions originating form the 1u(1D) ion-pair state. The identification of this new transition helped us to specify the wavelengths for detecting the 2g(1D) state by emission, and also to estimate its absolute position. The intermediate states used to observe the 2g(1D) state were the B 3Pi(0u(+))-b' 2u mixed states by the hyperfine interaction, which allowed us to combine the X 1Sigmag(+) ground state with the 2g(1D) state in the (1+1) photon excitation following the optical selection rules for one-photon transitions: 2g(1D)<--b' 2u-B 3Pi(0u(+))<--X 1Sigmag(+). Our analysis covered the 2g(1D) state in the 0< or =v< or =12 and 9< or =J< or =40 ranges. The molecular constants and Rydberg-Klein-Rees (RKR) potential of the 2g(1D) state were reported. We discussed the occurrence of the 2g(1D)-A' 3Pi(2u) emission, when exciting to the 1u(1D) v=0 state, and attributed it to the g/u mixing between the 2g(1D) and 1u(1D) states by the hyperfine interaction. The effect of the perturbation on measured line intensities and lifetimes was evident.     

FT-IR and theoretical study of 3,5-dimethyl-1H-pyrazole-1-carboxamidine (L) and the complexes CoL2(H2O)2(NO3)2, NiL2(H2O)2(NO3)2

In the paper a joint experimental and theoretical study of 3,5-dimethyl-1H-pyrazole-1-carboxamidine (L) as well as its complexes CoL2(H2O)2(NO3)2 and NiL2(H2O)2(NO3)2 is reported. On the basis of FT-IR experiments and a DFT-derived scaled quantum mechanical force field the normal coordinate analysis of L was carried out. The FT-IR spectra of the two complexes were interpreted using the present assignment of L and computed vibrational data of the complexes. The ionic and charge transfer interactions in the complexes were assessed by means of natural bond orbital (NBO) analysis.     

5,6-Dihydropyridin-2(1H)-ones and 5,6-dihydropyridine-2(1H)-thiones (review)

Data on methods for the production of 5,6-dihydropyridin-2(1H)-ones and 5,6-dihydropyridine-2(H)-thiones and their biological activity are reviewed.Omsk State University, Omsk, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 147–167, February, 1999.     

Self-assembly luminescent complexes with [Ag2 (μ-dppm)2 (MeCN)2](SbF6)2 and tptz as components

[Ag₂(μ-dppm)₂(tptz)(MeCN)](SbF₆)₂·2H₂O·2MeCN (1), [Ag₂(μ-dppm)₂(tptz)₂](SbF₆)₂·1.75H₂O (2) and [Ag₂(μ-dppm)(tptz)₂](SbF₆)₂· 2MeCN (3) were synthesized by self-assembly with metal diphosphine [Ag₂(μ-dppm)₂ (MeCN)₂](SbF₆) ₂ and tptz as components in different molar ratios [(dppm = bis(diphenylphosphino)methane and tptz = 2,4,6-tris(2′-pyridyl)-1,3,5-triazine)] and characterized by IR spectra, elemental analysis, ¹H NMR spectra, ³¹P NMR spectra and Visible–Ultraviolet spectra. Structures of all the complexes were determined by X-ray analysis. π − π interactions were found in complex (3). Further studies show that all the complexes were of well luminescent properties both in solution and solid state.     

Establishment and characterization of cell lines (Kagura-1 and Kagura-2) from aflatoxin B1-induced rat hepatoma

Two hepatoma cell lines designated Kagura-1 and Kagura-2 were established from rat hepatocellular carcinomas induced by aflatoxin B1, and have been propagated for over two years. Both cell lines grew as monolayered sheets with a population doubling time of about 20 h. Chromosome counts of Kagura-1 cells ranged from 34 to 45 with a modal number of 40, while that of Kagura-2 cells ranged widely from 40 to 130 with a modal number of 65. Subcutaneous inoculation of cultured cells of both these lines into nude mice resulted in tumor formation. The histopathological appearances of the induced tumors were similar to those of the original tumors. Kagura-1 and Kagura-2 cell lines express at least two tumor markers, glutathione-S-transferase P and gamma-glutamyl transpeptidase; the level of c-myc messenger ribonucleic acid was also highly elevated.     

Bubble-Point Data for the Systems: Bromobenzene(1)-Nitrobenzene(2) and Bromobenzene(1)-2-Nitrotoluene(2) at 200 and at 700 mm Hg

Abstract

The bubble-point data were collected on a Swietoslawski type ebulliometer for the title systems each at 200 and 700 mm Hg. Calculated VLE data along with the activity coefficients and excess gibbs free energy values through the use of the Wilson equation are reported. The data are analysed for the nonideal behaviour of the systems. The pure-component Vapour-Pressure-temperature relationships are also presented.