Isolation and spectral characterization of thermally generated multi-Z-isomers of lycopene and the theoretically preferred pathway to di-Z-isomers

Lycopene has a large number of geometric isomers caused by E/Z isomerization at arbitrary sites within the 11 conjugated double bonds, offering varying characteristics related to features such as antioxidant capacity and bioavailability. However, the geometric structures of only a few lycopene Z-isomers have been thoroughly identified from natural sources. In this study, seven multi-Z-isomers of lycopene, (9Z,13′Z)-, (5Z,13Z,9′Z)-, (9Z,9′Z)-, (5Z,13′Z)-, (5Z,9′Z)-, (5Z,9Z,5′Z)-, and (5Z,9Z)-lycopene, were obtained from tomato samples by thermal isomerization, and then isolated by elaborate chromatography, and fully assigned using proton nuclear magnetic resonance. Moreover, the theoretically preferred pathway from (all-E)-lycopene to di-Z-isomers was examined with a computational approach using a Gaussian program. Fine-tuning of the HPLC separation conditions led to the discovery of novel multi-Z-isomers, and whose formation was supported by advanced theoretical calculations.     

Interfacial friction and substrate deformation mediate long-range signal propagation in tissues

Biomechanics and Modeling in Mechanobiology - Tissue layers can generally slide at the interface, accompanied by the dissipation due to friction. Nevertheless, it remains elusive how force could...     

A point mutation at the putative ATP-binding site of protein kinase C alpha abolishes the kinase activity and renders it down-regulation-insensitive. A molecular link between autophosphorylation and down-regulation

A protein kinase C alpha (PKC alpha) cDNA confers increased phorbol ester binding activity to intact cells when transiently expressed in COS cells or expressed stably in transfected rat 3Y1 fibroblasts. A point mutant (PKC alpha K----R) of PKC alpha, where Lys368 at the putative ATP-binding site is replaced with Arg, confers enhanced phorbol ester binding activity to both transiently and stably expressed COS and 3Y1 cells, respectively. Like endogenous and exogenously expressed wild type PKC alpha, the mutant PKC alpha K----R is translocated from the cytosol to the particulate fraction when cells are treated with a phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). On the other hand, the mutant PKC alpha K----R is not degraded when cells are treated with TPA, making a clear contrast to wild type PKC alpha; i.e. the mutant is resistant to TPA-mediated down-regulation. The mutant lacks kinase activity as expected, as judged by autophosphorylation and by a kinase assay using a peptide substrate, although the phorbol ester binding activity remains intact. These results suggest a link between the kinase activity of PKC alpha and the sensitivity to TPA-mediated proteolytic degradation. We propose that autophosphorylation of PKC alpha is a prerequisite for proteolytic cleavage associated with the down-regulation of PKC alpha.     

Sodium and Chloride Ion-Dependent Transport of β-Alanine Across the Blood-Brain Barrier

Abstract: The characteristics of β-alanine transport at the blood-brain barrier were studied by using primary cultured bovine brain capillary endothelial cells. Kinetic analysis of the β-[³H]alanine transport indicated that the transporter for β-alanine functions with K_t of 25.3 ± 2.5 µ M and J _max of 6.90 ± 0.48 nmol/30 min/mg of protein in the brain capillary endothelial cells. β-[³H]Alanine uptake is mediated by an active transporter, because metabolic inhibitors (2,4-dinitrophenol and NaN₃) and low temperature reduced the uptake significantly. Furthermore, the uptake of β-[³H]alanine required Na⁺ and Cl⁻ in the external medium. Stoichiometric analysis of the transport demonstrated that two sodium ions and one chloride ion are associated with one β-alanine molecule. The Na⁺ and Cl⁻-dependent uptake of β-[³H]alanine was stimulated by a valinomycin-induced inside-negative K⁺-diffusion potential. β-Amino acids (β-alanine, taurine, and hypotaurine) inhibited strongly the uptake of β-[³H]alanine, whereas α- and γ-amino acids had little or no inhibitory effect. In ATP-depleted cells, the uptake of β-[³H]alanine was stimulated by preloading of β-alanine or taurine but not l -leucine. These results show that β-alanine is taken up by brain capillary endothelial cells, via the secondary active transport mechanism that is common to β-amino acids.     

Studies on the ɛ-Lysine Acylase

Since Achromobacter pestifer EA isolated from soils shows markedly high ?-Iysine acylase activity compared with those of the other microorganisms ever tested, cultural conditions for the production of this enzyme were investigated.

As a result, it was confirmed that simple medium containing 1% peptone, 5% glucose and some inorganic salts is most suitable for the enzyme production and that much more ?-Iysine acylase is produced by shaken culture or submerged culture in jar fermentor than by stationary culture. α-Amino acylase activity in this organism was also studied.     

Studies on the ɛ-Lysine Acylase

?-Lysine acylase of Achromobacter pestifer EA was purified by fractionations with ammonium sulfate and acetone, and by vertical zone electrophoresis. As a result, this bacterial ?-lysine acylase was obtained as an electrophoretically homogeneous protein, specific activity of which is the highest among ?-lysine acylases ever reported.     

Biochemical characterization of photosystem I complexes having different subunit compositions of fucoxanthin chlorophyll a/c-binding proteins in the diatom Chaetoceros gracilis

Photosynthesis Research - Diatoms are dominant phytoplankton in aquatic environments and have unique light-harvesting apparatus, fucoxanthin chlorophyll a/c-binding protein (FCP). Diatom...     

Changes of DNA methylation level during pre-and postnatal periods in mice

DNA methylation in an adult mammalian body shows tissue-specificity. But when and how the specificity is established in the process of development has not yet been elucidated. Here we have investigated age-dependent changes in the amount of 5-methyldeoxycytidine (5mdC) that DNA of various mouse tissues contains during the late-fetal and postnatal periods, using high-performance liquid chromatography. The tissue-specificity in the 5mdC level was observed in the late-fetal stage, and the level continued to change during the subsequent periods. The most pronounced alterations were observed in brain and liver, where similar biphasic changes were seen, but at different ages. At maturation, the 5mdC levels were high in thymus, spleen and brain, intermediate in lung, and low in liver and sperm. The data demonstrate the importance of the peri- and postnatal periods in establishment of tissue-specificity in 5mdC content.     

Most apoptotic cells in mdx diaphragm muscle contain accumulated lipofuscin

An age-related pigment, lipofuscin (LF), which accumulates in postmitotic, long-lived cells, is formed by the oxidative degradation of cellular macromolecules by oxygen-derived free radicals. In the present study we show that LF is accumulated in some myofibres, myosatellite cells and interstitial cells in the diaphragm muscles of the X chromosome-linked muscular dystrophic (mdx) mice at the age of 10 weeks when repetitive cycles of de- and regeneration of myofibres occur. In contrast, LF is virtually absent in diaphragm muscles of age-matched C57BL/10 (C57) normal control mice. Therefore, mdx muscle is more susceptible to oxidative stress than normal muscle. We hypothesise that gene-regulated cell death (apoptosis) occurs in dystrophic muscle cells that accumulate LF as a consequence of either oxidative stress or injury. We found that 74-79% of apoptotic myosatellite cells, interstitial cells and myofibres in mdx diaphragm contain accumulated or dotted LF granules, but only 12-20% of non-apoptotic cells contain LF. Apoptotic cells are very rare in the diaphragm of age-matched C57 control mice. This suggests that the regeneration of mdx diaphragm muscle initiated from myosatellite cells is impaired by their apoptosis as the result of either oxidative stress or a product of oxidative injury.