The effects of salivary gland extracts from Boophilus microplus ticks on mitogen-stimulated bovine lymphocytes

The effect of salivary gland extract (SGE) from the tick Boophilus microplus was examined in mitogen-stimulated lymphocytes in vitro. SGE was added to lymphocytes of seven cattle together with the mitogens concanavalin A (ConA), phytohaemagglutinin (PHA) and pokeweed mitogen (PWM). Semi-purified B cells from another seven cattle were stimulated with the mitogen lipopolysaccharide (LPS). PHA and ConA stimulated proliferation of lymphocytes to the same extent, but the inhibition due to SGE of Boophilus microplus on the proliferative response stimulated by PHA (39.0% ± 9.3%) was less than the inhibition of proliferative response stimulated by ConA (75.4% ± 6.9%). In contrast, SGE of B. microplus stimulated the proliferation of B cells in the presence of LPS in a dose-dependent manner. Enhanced stimulation of B cells by SGE at >4 μg in culture was greater than twice that observed when B cells were stimulated by LPS alone. SGE does not have a direct suppressive effect on bovine B cell proliferation; however, in vivo the effectiveness of B cell responses might be influenced by other immune factors, such as cytokine profiles.

Rapid isolation and detection of erythropoietin in blood plasma by magnetic core gold nanoparticles and portable Raman spectroscopy

Isolating, purifying, and identifying proteins in complex biological matrices is often difficult, time consuming, and unreliable. Herein we describe a rapid screening technique for proteins in biological matrices that combines selective protein isolation with direct surface enhanced Raman spectroscopy (SERS) detection. Magnetic core gold nanoparticles were synthesised, characterised, and subsequently functionalized with recombinant human erythropoietin (rHuEPO)-specific antibody. The functionalized nanoparticles were used to capture rHuEPO from horse blood plasma within 15 minutes. The selective binding between the protein and the functionalized nanoparticles was monitored by SERS. The purified protein was then released from the nanoparticles’ surface and directly spectroscopically identified on a commercial nanopillar SERS substrate. ELISA independently confirmed the SERS identification and quantified the released rHuEPO. Finally, the direct SERS detection of the extracted protein was successfully demonstrated for in-field screening by a handheld Raman spectrometer within 1 minute sample measurement time.

Raman Spectra of NaLa(MoO,), Single Crystal

The Raman spectra of NaLa(MoO4)2 single crystal have been recorded and interpreted on the basis of C4h symmetry. The observed fundamentals (internal and external) have been assigned unambiguously with the help of polarization data. All the group theoretically predicted Raman active fundamentals have been observed.

Influence of Solvent on Photoinduced Electron-Transfer Reaction: Time-Resolved Resonance Raman Study

Time-resolved resonance Raman spectroscopy (TR3) has been used to study the effect of solvent polarity on the mechanism and nature of intermediates formed in photoinduced electron-transfer reaction between triplet flouranil ((FL)-F-3) and tetramethylbenzene (TMB). Comparison of the TR3 spectra in polar, nonpolar, and medium polar media suggests that formation of radical anion due to electron-transfer reaction between (FL)-F-3 and TMB is favored in more polar solvents, whereas ketyl radical formation is more favored in less polar media. Compared to ketyl radical, the extent of radical anion formation is negligible in nonpolar solvents. Therefore, it is inferred that in nonpolar media ketyl radical is mainly generated by hydrogen-transfer reaction in the encounter complex between (FL)-F-3 and TMB. In solvents of medium polarity, the ion-pair decay leads to the formation of both ketyl radical and ketyl radical formed from the encounter between triplet state and the donor. Thus, competition between the formation of ketyl radical and ion pair is influenced by the solvent polarity. The nature of the ion pair in different solvent polarity has been investigated from the changes observed in the vibrational frequency of (fluoranil) FL part of the complex.

Renormalization of the phonon spectrum in semiconducting single-walled carbon nanotubes studied by Raman spectroscopy

In situ Raman experiments together with transport measurements have been carried out in single-walled carbon nanotubes as a function of electrochemical top gate voltage (Vg). We have used the green laser (EL=2.41 eV), where the semiconducting nanotubes of diameter ~1.4 nm are in resonance condition. In semiconducting nanotubes, the G−- and G+-mode frequencies increase by ~10 cm−1 for hole doping, the frequency shift of the G− mode is larger compared to the G+ mode at the same gate voltage. However, for electron doping the shifts are much smaller: G− upshifts by only ~2 cm−1 whereas the G+ does not shift. The transport measurements are used to quantify the Fermi-energy shift (EF) as a function of the gate voltage. The electron-hole asymmetry in G− and G+ modes is quantitatively explained using nonadiabatic effects together with lattice relaxation contribution. The electron-phonon coupling matrix elements of transverse-optic (G−) and longitudinal-optic (G+) modes explain why the G− mode is more blueshifted compared to the G+ mode at the same Vg. The D and 2D bands have different doping dependence compared to the G+ and G− bands. There is a large downshift in the frequency of the 2D band (~18 cm−1) and D (~10 cm−1) band for electron doping, whereas the 2D band remains constant for the hole doping but D upshifts by ~8 cm−1. The doping dependence of the overtone of the G bands (2G bands) shows behavior similar to the dependence of the G+ and G− bands.

Raman and polarized infrared spectra of pyridine-2-thione

Polarized i.r. spectra of oriented polycrystals and the i.r. and Raman spectra of polycrystalline samples of pyridine-2-thione have been obtained. The Raman spectra of a solution of pyridine-2-thione has also been measured and the polarization of many lines determined. The i.r. spectra of S-methyl and N-deuterated compounds have also been investigated. A complete assignment of all the observed peaks has been possible. The results are correlated with the assignments available for related systems.

Structural origin of set-reset processes in Ge15Te83Si2 glass investigated using in situ Raman scattering and transmission electron microscopy

We report here that the structural origin of an easily reversible Ge15Te83Si2 glass can be a promising candidate for phase change random access memories. In situ Raman scattering studies on Ge15Te83Si2 sample, undertaken during the amorphous set and reset processes, indicate that the degree of disorder in the glass is reduced from off to set state. It is also found that the local structure of the sample under reset condition is similar to that in the amorphous off state. Electron microscopic studies on switched samples indicate the formation of nanometric sized particles of c-SiTe2 structure. ©2009 American Institute of Physics

Surface-enhanced Raman scattering of molecules adsorbed on nanocrystalline Au and Ag films formed at the organic-aqueous interface

Surface-enhanced Raman scattering (SERS) of pyridine adsorbed on ultrathin nanocrystalline Au and Ag films generated at the liquid-liquid interface has been investigated. The shifts and intensification of bands formed with these films comprising metal nanoparticles are comparable to those found with other types of Au and Ag substrates. SERS of rhodamine 6G adsorbed on Ag films has also been studied. The results demonstrate that nanocrystalline metal films prepared by the simple method involving the organic-aqueous interface can be used effectively for SERS investigations.

Laser Raman spectra of semicarbazide hydrobromide

Semicarbazide hydrobromide which is isomorphous with SEM.HCl, was expected to belong to a new family of ferroelectrics. Dielectric, thermal and other studies on these crystals have yielded results which show many peculiarities but not confirmed ferroelectricity in the low temperature phase. As such a Laser Raman spectrosocopic study of oriented singe crystals of SEM.HBr was made at 298°K and at 253°K. The results have been correlated with structural features and compared with SEM.HCl.

A vanadate-stimulated NADH oxidase in erythrocyte membrane generates hydrogen peroxide

Oxidation of NADH by rat erythrocyte plasma membrane was stimulated by about 50-fold on addition of decavanadate, but not other forms of vanadate like orthovanadate, metavanadate aad vanadyl sulphate. The vanadate-stimulated activity was observed only in phosphate buffer while other buffers like Tris, acetate, borate and Hepes were ineffective. Oxygen was consumed during the oxidation of NADH and the products were found to be NAD+ and hydrogen peroxide. The reaction had a stoichiometry of one mole of oxygen consumption and one mole of H2O2 production for every mole of NADH that was oxidized. Superoxide dismutase and manganous inhibited the activity indicating the involvement of superoxide anions. Electron spin resonance in the presence of a spin trap, 5, 5prime-dimethyl pyrroline N-oxide, indicated the presence of superoxide radicals. Electron spin resonance studies also showed the appearance of VIV species by reduction of VV of decavanadate indicating thereby participation of vanadate in the redox reaction. Under the conditions of the assay, vanadate did not stimulate lipid peroxidation in erythrocyte membranes. Extracts from lipid-free preparations of the erythrocyte membrane showed full activity. This ruled out the possibility of oxygen uptake through lipid peroxidation. The vanadate-stimulated NADH oxidation activity could be partially solubilized by treating erythrocyte membranes either with Triton X-100 or sodium cholate. Partially purified enzyme obtained by extraction with cholate and fractionation by ammonium sulphate and DEAE-Sephadex was found to be unstable.

Vanadate-stimulated NADH oxidation by xanthine oxidase: An intrinsic property

Vanadate-dependent oxidation of NADH by xanthine oxidase does not require the presence of xanthine and therefore is not due to cooxidation. Addition of NADH or xanthine had no effect on the oxidation of the other substrate. Oxidation of NADH was high at acid pH and oxidation of xanthine was high at alkaline pH. The specific activity was relatively very high with NADH. Concentration-dependent oxidation of NADH was obtained in the presence of the polymeric form of vanadate, but not orthovanadate or metavanadate. Both NADH and NADPH were oxidized, as in the nonenzymatic system. Oxidation of NADH, but not xanthine, was inhibited by KCN, ascorbate, MnCl2, cytochrome c, mannitol, Tris, epinephrine, norepinephrine, and triiodothyronine. Oxidation of NADH was accompanied by uptake of oxygen and generation of H2O2 with a stoichiometry of 1:1:1 for NADH:O2:H2O2. A 240-nm-absorbing species was formed during the reaction which was different from H2O2 or superoxide. A mechanism of NADH oxidation is suggested wherein VV and O2 receive one electron each successively from NADH followed by VIV giving the second electron to superoxide and reducing it to H2O2.

Possible involvement of a calcium-stimulated ATP-hydrolyzing activity associated with mycobacteriophage I3 in the DNA injection process.

Ca2+ ions are necessary for the successful propagation of mycobacteriophage I3. An assay for the phage DNA release in the presence of an isolated cell wall preparation from the host was established, and in this system Ca2+ ions also stimulated the release of DNA. The inhibition of phage DNA injection caused by Tween 80 (polyoxyethylene sorbitan monooleate), a nonionic detergent routinely used in mycobacterial cultures, was reversed by Ca2+. The presence of a phage-associated ATP-hydrolyzing activity was demonstrated. This enzyme was stimulated by Ca2+ ions and inhibited by Tween 80. From this and the behavior of the two agents at the level of DNA injection, as well as the fact that phage I3 has a contractile tail structure, we conclude that the phage-associated ATPase is involved in the DNA injection process.

Intensity of a Raman Overtone Band

Placzek [1] was the first to derive general expressions for the intensities of overtones in case of Raman scattering. He assumed electrical anharmonicity. However, he left the expressions for the derivations of the polarizability tensor undetermined. In 1941, a classical and semiempirical theory was developed by Wolkenstein [2]. He assumed the validity of the additivity of bond polarizabilities. However, the expressions derived by him for the intensities of overtones remain yet to be verified. It is the purpose of this paper to derive a formula for Raman polarizability tensor for overtones of (intramolecular) vibrational spectra along the lines of Kondilenko et al. [3,4].

Laser Raman spectroscopic study of ferroelastic LiCsSO4

Lithium caesium sulphate has been reported to undergo a phase transition from the room temperature orthorhombic phase with space groupP cmn to a final phase with space groupP 22/n. Though a sharp anomaly in its physical properties has been found at 202.0;K, it was found that there was a need for careful investigations in the vicinity of 240 and 210.0;K. Since the changes in the crystal structure involve primarily a rotation of the SO4 tetrahedron about thec-axis and as this may be reflected both in the intensity and polarisation of the internal as well as external phonon modes, the laser Raman spectra of oriented single crystals of LiCsSO4 at different temperatures were investigated. For correlation and definite identification of the spectral features, its infrared absorption spectrum was also studied. An analysis of the intensities and polarizations of the internal modes of the sulphate ions reveals the change in symmetry of the crystal. The integrated intensity and peak height of thev 1 line, plotted against temperature show anomalous peaks in the region of the phase transition. Differential scanning calorimetric study gives the enthalpy change ΔH across the phase transition to be 0.213 kJ/mol.

High-throughput prediction of eucalypt lignin syringyl/guaiacyl content using multivariate analysis: a comparison between mid-infrared, near-infrared, and Raman spectroscopies for model development

BACKGROUND: In order to rapidly and efficiently screen potential biofuel feedstock candidates for quintessential traits, robust high-throughput analytical techniques must be developed and honed. The traditional methods of measuring lignin syringyl/guaiacyl (S/G) ratio can be laborious, involve hazardous reagents, and/or be destructive. Vibrational spectroscopy can furnish high-throughput instrumentation without the limitations of the traditional techniques. Spectral data from mid-infrared, near-infrared, and Raman spectroscopies was combined with S/G ratios, obtained using pyrolysis molecular beam mass spectrometry, from 245 different eucalypt and Acacia trees across 17 species. Iterations of spectral processing allowed the assembly of robust predictive models using partial least squares (PLS). RESULTS: The PLS models were rigorously evaluated using three different randomly generated calibration and validation sets for each spectral processing approach. Root mean standard errors of prediction for validation sets were lowest for models comprised of Raman (0.13 to 0.16) and mid-infrared (0.13 to 0.15) spectral data, while near-infrared spectroscopy led to more erroneous predictions (0.18 to 0.21). Correlation coefficients (r) for the validation sets followed a similar pattern: Raman (0.89 to 0.91), mid-infrared (0.87 to 0.91), and near-infrared (0.79 to 0.82). These statistics signify that Raman and mid-infrared spectroscopy led to the most accurate predictions of S/G ratio in a diverse consortium of feedstocks. CONCLUSION: Eucalypts present an attractive option for biofuel and biochemical production. Given the assortment of over 900 different species of Eucalyptus and Corymbia, in addition to various species of Acacia, it is necessary to isolate those possessing ideal biofuel traits. This research has demonstrated the validity of vibrational spectroscopy to efficiently partition different potential biofuel feedstocks according to lignin S/G ratio, significantly reducing experiment and analysis time and expense while providing non-destructive, accurate, global, predictive models encompassing a diverse array of feedstocks.