A radio-gas chromatographic method for determining the specific radioactivity of glycolic acid in -14C-labeled leaf tissue.

A method for the extraction and quantitative determination of both the mass and radioactivity of glycolic acid from -14C-labeled leaf tissue is described. The recoveries of both mass and radioactivity from standard [1-14C]glycolic acid solutions averaged 98 percent, and recovery of radioactivity added to plant samples as [1-14C]glycolic acid was over 90 percent after the complete procedure. The method was reliable with total samples containing as little as 130 nmol of glycolic acid. The mass of glycolic acid recovered from sunflower leaf tissue was proportional to the amount of tissue extracted. In experiments with different plant material, the amount of glycolic acid varied between 530 and 1120 nmol/dm-2 of leaf tissue. The specific radioactivity of the glycolic acid in sunflower leaf tissue during photosynthesis in -14CO(2) was never more than 20 percent of the specific radioactivity of the -14CO(2) supplied.     

Analysis of the nuclear envelope polypeptides by isoelectric focusing and electrophoresis

The more insoluble polypeptides of the avian erythrocyte nuclear envelope have been characterized by a two-dimensional electrophoretic procedure. Most of the polypeptides occur in two classes with isoelectric points of approximately 6.4 and 5.7 respectively. The more acidic class contains two polypeptides, P71 and one which contributes to an electrophoretic band previously identified as P55. The more basic class includes P75, P68, P61 and two or more polypeptides from the P55 band. There are four to six isoelectric point variants of each polypeptide in the more basic class, and the relative stain intensities for the variants are similar for the different polypeptides. These similarities in ionic properties suggest a chemical relationship between the polypeptides. These results are discussed in relation to the in vitro conversion of P75 to polypeptides of the same molecular weight as P68, P61 and P55.     

The effects of xylanase type enzymes on the different layers of birch wood ORGANOSOLV pulp fibre walls

Some effects of the xylanase treatment on the separate birch ORGANOSOLV pulp fibre wall morphological layers were examined. These investigations were focused on the outer layers, i.e. the primary wall (P) and the outer layer of the secondary wall (S₁), as well as the central layers, i.e. the central layer of the secondary wall (S₂) and the tertiary wall (T). Step by step, the fractionation of the pulp components in the polar solvents N,N-dimethylformamide (DMFA), dimethylsulphoxide (DMSO) and DMSO/H₃PO₄ was used as a mild technique for the isolation of the lignin-carbohydrate complexes. The different residual amounts of lignin and hemicelluloses in the outer and central pulp fibre wall layers as well as the different lignin-hemicellulose ratios were determined. The size-exclusion chromatographical (SEC) analysis showed a higher initial lignin content in the region of the high molecular mass (MM) fibre wall fraction extracted with “DMSO/H₃PO₄” than the outer cell wall layers. In the central layers, the amounts of soluble lignin (calculated on the mass of total dissolved substance) were approximately the same for all the three solvents. The xylanase treatment brought the most considerable changes in the high MM part of the residual lignin (the lignin carbohydrate complex). This was true for both the P-S₁ and S₂-T layers. The careful brightness comparison of the outer and central fractions after the X-E-P-P bleaching sequence showed a surprisingly low bleachability of the outer layer fraction. The xylanase action depended on the composition of the lignin-carbohydrate complex (LCC) and the extent of the maintenance of the outer layers during the pulping process.     

Zur Kenntnis des Lichtfeldes der Pflanze und der Blattfarbstoffe

Ohne ZusammenfassungMit 15 Textabbildungen.     

<Emphasis Type="SmallCaps">l</Emphasis>-Arginine Suppresses Aggregation of Recombinant Growth Hormones in Refolding Process from <Emphasis Type="Italic">E. coli</Emphasis> Inclusion Bodies

l-Arginine was used to suppress the aggregation of recombinant mink and porcine growth hormones in the refolding process from E. coli inclusion bodies by solubilization–dilution protocol at high protein concentration and pH 8.0. The influence of l-arginine concentration on the renaturation yield of both proteins was investigated. l-Arginine effectively suppressed the precipitation of growth hormones during dilution, but did not inhibit soluble oligomers formation. The results of mink and porcine growth hormones purification from 4 g of biomass are presented.     

Brazilian Savanna Fruits Contain Higher Bioactive Compounds Content and Higher Antioxidant Activity Relative to the Conventional Red Delicious Apple

The bioactive compounds content and the antioxidant activity (AA) of twelve fruits native to the Cerrado were compared with the Red Delicious apple by means of the antiradical efficiency (using the 2,2-diphenyl-1-picrylhydrazil assay/DPPH), ferric reducing antioxidant power (FRAP) and the β-carotene/linoleic system. The antiradical efficiency (AE) and the kinetic parameters (Efficient concentration/EC₅₀ and time needed to reach the steady state to EC₅₀ concentration/TEC₅₀) of the DPPH curve were also evaluated for comparison with the Trolox equivalent (TE) values. A strong, significant and positive correlation was observed between the TE and AE values, whereas a weak and negative correlation was observed between TE and EC_50, suggesting that the values of AE and TE are more useful for the determination of antiradical activity in fruits than the widely used EC₅₀. The total phenolic content found in the fruits corresponded positively to their antioxidant activity. The high content of bioactive compounds (flavanols, anthocyanins or vitamin C) relative to the apple values found in araticum, cagaita, cajuzinho, jurubeba, lobeira, magaba and tucum corresponded to the high antioxidant activity of these fruits. Flavanols and anthocyanins may be the main bioactive components in these Cerrado fruits. The daily consumption of at least seven of the twelve Cerrado fruits studied, particularly, araticum, cagaita, lobeira and tucum, may confer protection against oxidative stress, and thus, they may prevent chronic diseases and premature aging. The findings of this study should stimulate demand, consumption and cultivation of Cerrado fruits and result in sustainable development of the region where this biome dominates.     

Vitamin D and physical performance in elderly subjects: the Pro.V.A study

Background

The role of Vitamin D in musculoskeletal functionality among elderly people is still controversial. We investigated the association between serum 25-hydroxyvitamin D (25OHD) levels and physical performance in older adults.

Methods

2694 community-dwelling elderly women and men from the Progetto Veneto Anziani (Pro.V.A.) were included. Physical performances were assessed by: tandem test, 5 timed chair stands (TCS), gait speed, 6-minute walking (6 mW) distance, handgrip strength, and quadriceps strength. For each test, separate general linear models and loess plots were obtained in both genders, in relation to serum 25OHD concentrations, controlling for several potential confounders.

Results

Linear associations with 25OHD levels were observed for TCS, gait speed, 6 mW test and handgrip strength, but not for tandem test and quadriceps strength. After adjusting for potential confounders, linear associations with 25OHD levels were still evident for the 6 mW distance in both genders (p = .0002 in women; <.0001 in men), for TCS in women (p = .004) and for gait speed (p = .0006) and handgrip strength (p = .03) in men. In loess analyses, performance in TCS in women, in gait speed and handgrip strength in men and in 6 mW in both genders, improved with increasing levels of 25OHD, with most of the improvements occurring for 25OHD levels from 20 to 100 nmol/L.

Conclusion

lower 25OHD levels are associated with a worse coordination and weaker strength (TCS) in women, a slower walking time and a lower upper limb strength in men, and a weaker aerobic capacity (6 mW) in both genders. For optimal physical performances, 25OHD concentrations of 100 nmol/L appear to be more advantageous in elderly men and women, and Vitamin D supplementation should be encouraged to maintain their 25OHD levels as high as this threshold.     

Biomimetic apatite coatings--carbonate substitution and preferred growth orientation

Biomimetic apatite coatings were obtained by soaking chemically treated titanium in SBF with different HCO(3)(-) concentration. XRD, FTIR and Raman analyses were used to characterize phase composition and degree of carbonate substitution. The microstructure, elemental composition and preferred alignment of biomimetically precipitated crystallites were characterized by cross-sectional TEM analyses. According to XRD, the phase composition of precipitated coatings on chemically pre-treated titanium after exposure to SBF was identified as hydroxy carbonated apatite (HCA). A preferred c-axis orientation of the deposited crystals can be supposed due to the high relative peak intensities of the (002) diffraction line at 2theta=26 degrees compared to the 100% intensity peak of the (211) plane at 2theta=32 degrees . The crystallite size in direction of the c-axis of HCA decreased from 26 nm in SBF5 with a HCO(3)(-) concentration of 5 mmol/l to 19 nm in SBF27 with a HCO(3)(-) concentration of 27 mmol/l. Cross-sectional TEM analyses revealed that all distances correspond exactly to the hexagonal structure of hydroxyapatite. The HCO(3)(-) content in SBF also influences the composition of precipitated calcium phosphates. Biomimetic apatites were shown to have a general formula of Ca(10-x-y)Mg(y)(HPO(4))(x-z)(CO(3))(z)(PO(4))(6-x)(OH)(2-x-w)(CO(3))(w/2). According to FTIR and Raman analyses, it can be supposed that as long as the HCO(3)(-) concentration in the testing solutions is below 20 mmol/l, only B-type HCA (0相似文献   

Src SH3/2 domain-mediated peripheral accumulation of Src and phospho-myosin is linked to deregulation of E-cadherin and the epithelial-mesenchymal transition

Elevated Src kinase in epithelial cancer cells induces adhesion changes that are associated with a mesenchymal-like state. We recently showed that Src induces dynamic integrin adhesions in KM12C colon cancer cells, whereas E-cadherin-dependent cell-cell contacts become disorganized. This promotes a fibroblastic-like morphology and expression of the mesenchymal marker vimentin. Furthermore, Src-induced deregulation of E-cadherin, and the associated mesenchymal transition, is dependent on integrin signaling (Avizienyte et al., Nat. Cell Biol. 2002, 4, 632-638), although the nature of downstream signals that mediate these Src- and integrin-dependent effects are unknown. Here we show that the SH2 and SH3 domains of Src mediate peripheral accumulation of phospho-myosin, leading to integrin adhesion complex assembly, whereas loss of SH2 or SH3 function restores normal regulation of E-cadherin and inhibits vimentin expression. Inhibitors of MEK, ROCK, or MLCK also suppress peripheral accumulation of phospho-myosin and Src-induced formation of integrin-dependent adhesions, whereas at the same time restoring E-cadherin redistribution to regions of cell-cell contact. Our data therefore implicate peripheral phospho-myosin activity as a point of convergence for upstream signals that regulate integrin- and E-cadherin-mediated adhesions. This further implicates spatially regulated contractile force as a determinant of epithelial cell plasticity, particularly in cancer cells that can switch between epithelial and mesenchymal-like states.