A pulsed NMR study of lipids,bound water and sodium ions in macroscopically-oriented lecithin/water lyotropic liquid crystal model membrane systems

The temperature and orientation dependence of pulsed NMR ‘free induction decay’ signals have been studied in detail for lipid bilayers macroscopically-oriented between glass slides. Results for the lipid molecules (¹H, ³¹P), bound water (²H₂O) and ions dissolved in the aqueous phase (²³Na) are presented. Bilayers of egg-lecithin, dimyristoyl lecithin and potassium oleate have been investigated. In the liquid crystal phase all the signals, including those from bound water and ions exhibit a |3 cos²? ? 1| dependence on orientation of the bilayer normal to the magnetic field. In the case of DML samples, some orientation dependence of both ¹H and ²H signals persists in the gel phase, indicating that the lipid molecules retain a degree of reorientational freedom about their long axes in this phase. At the gel-liquid crystal transition the ²H quadrupole spittings undergo a discontinuous change. Results are interpreted in terms of a model in which water molecules are bound to individual lipid head groups and reorient with them, while sodium ions are located in the aqueous channel between bilayers.     

Hyperfine shift NMR studies of hydrated phospholipid inverted micelles

The ³¹P nuclear magnetic resonance (NMR) spectra of benzene solutions of hydrated dipalmitoyl lecithin (DPL) inverted micelles, with and without incorporated paramagnetic lanthanide ions, have been recorded. Individual resonances for micelles containing none, one, and two ions can be resolved and observed in the presence of one another. The relative intensities of these peaks yield some information on the state of aggregation of lipid inverted micelles prepared by ultrasonic irradiation. The relative intensities and chemical shifts of resonances of unsonicated mixtures of preformed micelles containing different numbers of ions per micelle indicate that some kind of equilibration occurs. The data are consistent with a selective fusion of multi-ion micelles with ion-free micelles. The NMR spectra place constraints on the lifetimes of metal ions and lipid and water molecules within a micelle before transfer to another.     

Dynamic fluorescence investigations of the effect of osmotic shocks on the microenvironments of charged and uncharged dipalmitoyl-D,L-α-phosphatidylcholine liposomes

Neutral methylanthracene (MA), anionic trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate, (pyranine), and cationic 3,6-diamino-10-methylacridinium chloride (acriflavine), have been used as fluorescence probes to investigate effects of osmotic shrinkage on neutral, cationic and anionic dipalmitoyl-D,L-α-phosphatidylcholine liposomes. The determined fluorescence polarizations in the liposomes and in solvents of known viscosities afforded the estimation of the microviscosities of the environments of these probes. The viscosity reported by pyranine for anionic and that by acriflavine for cationic single compartment liposomes, ～1.0 cP, indicate the aqueous environments of these probes. Increased viscosities following osmotic shrinkages have been rationalized in terms of changing the nature of the liposome entrapped water. Following the release of free water, some bound water is also released as the result of osmotic shrinkage. The determined shrinkage rates support this postulate. The viscosity of the environment of pyranine in cationic, 9.6 ± 0.3 cP, and that of acriflavine in anionic single compartment liposomes, 74 ± 5 cP, indicate electrostatic attractions of the probes to the charged liposome surface. Osmotic shrinkage results in lowering the viscosity of the environments of the probes presumably because the more concentrated sodium chloride replaces them from their sites. The high viscosities reported by MA, ～ 1000 cP, suggest the intercalation of this probe in the phospholipid bilayers. Osmotic shrinkage does not alter the environment of MA. However, in the presence of cholesterol, the viscosities reported by MA are greater than in its absence. These data contradict previous NMR, ESR and X-ray results as well as those obtained in the present work from osmotic shrinkage rates. The need for care in interpreting data obtained by the use of fluorescence probes is emphasized.     

Cereal type in diet and housing system influences on growth performance and carcass yield in two Japanese quail genotypes

We assessed the effects of cereal type (corn-based, CB or rice-based, RB) and housing system (floor, F, or cage, C) on the performance of two Japanese quail genotypes (non-selected, JAP, and a Jumbo variety, JUM) in two, 2 × 2 factorially designed, experiments. In Exp. 1, during the 15-d experimental period, there were 4 experimental groups: JAP quail fed the CB diet, JAP-CB; JAP quail fed the RB diet, JAP-RB; JUM quail fed the CB diet, JUM-CB; JUM quail fed the RB diet, JUM-RB. Quail in each of the 4 groups (42 quail/group) were housed in 7 pens, each with 6 birds. In Exp. 2, there were also 4 experimental groups (42 quail/group, 7 pens, each with 6 birds) examined during a 19-d experimental period under two different rearing systems: JAP-F, JUM-F, JAP-CF and JUM-C. Genotype did not affect dry matter feed intake (DMI) in Exp. 1, but both JAP and JUM quail consumed more (P<0.001) of the CB than RB diets. Average daily gain (ADG) was similarly higher (P<0.001) in JAP-CB and JUM-CB quail compared to the other 2 treatment groups. Feed conversion (FC) differed (P<0.001) as follows (best to worst): JUM-CB > JAP-CB = JAP-RB = JUM-RB. Final BW was similarly higher (P<0.001) in the JUM-CB, and JAP-CB groups compared to the JAP-RB and JUM-RB, groups and carcass yield (CY, P<0.001) differed as follows: JUM-RB = JUM-CB = JAP-RB > JAP-CB. In Exp. 2, DMI was similarly higher (P<0.05) in the JAP-C, JUM-F, and JUM-C groups compared to JAP-F quail and ADG was notably higher (P=0.07) in JUM-F quail than the other 3 groups. Regardless of housing system, FC was better (P=0.04) in JUM quail. Although final BW was higher (P<0.05) in F- than C-housed quail, CY was greater (P<0.01) in caged birds. Final BW and CY were unaffected by quail genome and its interaction with housing system. With a few exceptions, better performance was generally observed in quail fed diets containing corn regardless of genotype (Exp. 1), while C-reared JUM quail generally outperformed the other genotype × housing system groups (Exp. 2).     

Energy transfer from enzymically generated triplet carbonyl compounds to the fluorescent state of flavins

Enzymically generated triplet carbonyl compounds transfer energy to the fluorescent state of flavins as shown by the suppression of the carbonyl chemiphosphorescence and concomitant appearance of the flavin fluorescence. A Stern-Volmer analysis including the effect of the collisional quenching by a diene indicates that the transfer occurs by a long range process.The present results open the way to “photobiology without light”.     

A numerical study on dual-phase-lag model of bio-heat transfer during hyperthermia treatment

The success of hyperthermia in the treatment of cancer depends on the precise prediction and control of temperature. It was absolutely a necessity for hyperthermia treatment planning to understand the temperature distribution within living biological tissues. In this paper, dual-phase-lag model of bio-heat transfer has been studied using Gaussian distribution source term under most generalized boundary condition during hyperthermia treatment. An approximate analytical solution of the present problem has been done by Finite element wavelet Galerkin method which uses Legendre wavelet as a basis function. Multi-resolution analysis of Legendre wavelet in the present case localizes small scale variations of solution and fast switching of functional bases. The whole analysis is presented in dimensionless form. The dual-phase-lag model of bio-heat transfer has compared with Pennes and Thermal wave model of bio-heat transfer and it has been found that large differences in the temperature at the hyperthermia position and time to achieve the hyperthermia temperature exist, when we increase the value of τ_T. Particular cases when surface subjected to boundary condition of 1st, 2nd and 3rd kind are discussed in detail. The use of dual-phase-lag model of bio-heat transfer and finite element wavelet Galerkin method as a solution method helps in precise prediction of temperature. Gaussian distribution source term helps in control of temperature during hyperthermia treatment. So, it makes this study more useful for clinical applications.