The pollutants in rime and fog water and in air at Milesovka Observatory (Czech Republic)

Samples of rime/fog water and dust in the air were collected in order to compare concentrations of pollutants. Particular attention was paid to particles of heavy metals (Al, As, Cu, Fe, Pb, Ti and Zn). The concentrations of pollutants from the air are different in rime water and fog water. Both (fog) water and ice crystals fixed Ti, Cu, As and Pb ions minimally (less than 1%). Rime captured 11.6% Al, 9.3% Zn, 4.4% Fe and 91.2% Mn from the air. Fog water absorbed 9.8% Al, 9.0% Fe, 55.6% Mn, and 48.7% Zn from the air. Fog water absorbed Zn much better (48.7%) than rime (9.3%). Rime absorbed Mn better (91.2%) than fog water (55.6%).     

Glycosphingolipids in microdomain formation and their spatial organization

Plasma membranes regulate the influx and efflux of molecules across themselves and are also responsible for primary signal transduction between cells or within the same cell. Presence of lateral heterogeneity and the ability of reorganization are essential requirements for effective functioning of biomembranes. Lipid rafts are small, heterogeneous, dynamic domains enriched in glycosphingolipids, sphingomyelin and cholesterol, and profoundly influence membrane organization. Glycosphingolipids are inclined towards formation of liquid-ordered phases in membranes, both with and without cholesterol; they are therefore prime players in domain formation. Here, we discuss the role of glycosphingolipids in microdomain formation and their spatial organization within these rafts.     

Cholesterol but not association with detergent resistant membranes is necessary for the transport function of MRP2/ABCC2

MRP2(/ABCC2) excretes amphiphilic organic anions into bile, and associates with detergent-resistant bile canalicular membrane domains (DRM). Here, we have evaluated sensitivities of MRP2 transport function and DRM association by titrating the cellular cholesterol content. We demonstrate that the role of cholesterol in the partitioning of MRP2 to DRM can be separated from the role of cholesterol in the function of MRP2, such that (i) cholesterol is not necessary for the polarized distribution of MRP2 at the canalicular membrane, (ii) partitioning into DRM is not required for MRP2 function, yet (iii) the presence of cholesterol is necessary for transport activity.     

A Complex Connection Between the Diversity of Human Gastric Mucin O-Glycans,Helicobacter pylori Binding,Helicobacter Infection and Fucosylation

Helicobacter pylori colonizes the stomach of half of the human population. Most H. pylori are located in the mucus layer, which is mainly comprised by glycosylated mucins. Using mass spectrometry, we identified 631 glycans (whereof 145 were fully characterized and the remainder assigned as compositions) on mucins isolated from 14 Helicobacter spp.-infected and 14 Helicobacter spp.-noninfected stomachs. Only six identified glycans were common to all individuals, from a total of 60 to 189 glycans in each individual. An increased number of unique glycan structures together with an increased intraindividual diversity and larger interindividual variation were identified among O-glycans from Helicobacter spp.-infected stomachs compared with noninfected stomachs. H. pylori strain J99, which carries the blood group antigen–binding adhesin (BabA), the sialic acid–binding adhesin (SabA), and the LacdiNAc-binding adhesin, bound both to Lewis b (Leb)-positive and Leb-negative mucins. Among Leb-positive mucins, H. pylori J99 binding was higher to mucins from Helicobacter spp.-infected individuals than noninfected individuals. Statistical correlation analysis, binding experiments with J99 wt, and J99ΔbabAΔsabA and inhibition experiments using synthetic glycoconjugates demonstrated that the differences in H. pylori-binding ability among these four groups were governed by BabA-dependent binding to fucosylated structures. LacdiNAc levels were lower in mucins that bound to J99 lacking BabA and SabA than in mucins that did not, suggesting that LacdiNAc did not significantly contribute to the binding. We identified 24 O-glycans from Leb-negative mucins that correlated well with H. pylori binding whereof 23 contained α1,2-linked fucosylation. The large and diverse gastric glycan library identified, including structures that correlated with H. pylori binding, could be used to select glycodeterminants to experimentally investigate further for their importance in host–pathogen interactions and as candidates to develop glycan-based therapies.     

Impact of animal and management factors on collagen characteristics in beef: a meta-analysis approach

The aim of this paper was to identify pre-slaughter factors that modify total and insoluble collagen contents in bovine muscle to construct a model of collagen dynamics. The meta-analyses were performed with primary data of total (n = 1165) and insoluble (n = 1145) collagen contents from INRA experiments obtained from different muscles in young bulls, cows and steers. According to both the bibliography and meta-analyses, total collagen content and solubility were greatly affected by the muscle (type). Moreover, the pattern of the evolution of collagen characteristics was similar among Longissimus, Semitendinosus and Triceps brachii muscles in young bulls. In cows, collagen contents in the Triceps brachii muscle had delayed dynamics compared with the other muscles. Collagen characteristics differed among breeds because of variation in the maturity of the breed. Similarly, according to the meta-analyses, total and insoluble collagen content evolutions with the degree of maturity (DOM; proportion of adult weight reached at slaughter) were different in dairy and rustic breeds from those of beef breeds, especially in bulls. Although the relationships between collagen content and DOM were quantified in different muscles and sexes, the precision of the fitted equations was not sufficient for prediction. Consequently, relying on the hypotheses raised by the meta-analysis and the literature, an approach to further develop a dynamic mechanistic model of soluble and insoluble collagen content is proposed.     

Raft-like membrane domains contain enzymatic activities involved in the synthesis of mammalian glycosylphosphatidylinositol anchor intermediates

The synthesis of the glycosylphosphatidylinositol (GPI) anchor occurs in different compartments within the ER. We have previously shown that GPI anchor intermediates including GlcNAc-PI and GlcN-(acyl)PI are present in Triton insoluble membranes (TIMs), believed to be derived from lipid rafts. The present study was initiated to determine if GPI anchor intermediates move to raft-like domains after their synthesis or if these domains represent another ER compartment for GPI anchor synthesis. We determined that in transfected cells Pig-Ap and Pig-Lp, two proteins involved in the synthesis of GlcNAc-PI and GlcN-PI, respectively, are present in TIMs. In addition, we detected GlcNAc-PI synthase, GlcNAc-PI deacetylase, and GlcN-PI acyltransferase activities in TIMs isolated from untransfected cells. These results lend support to the possibility of additional GPI biosynthetic compartments in the ER and to the notion that GPI anchor intermediates produced in and outside raft-like domains may have a different fate.     

Synthesis and characterization of fructooligosaccharides using levansucrase with a high concentration of sucrose

A method for synthesizing branched fructo-oligosaccharides (BFOS) with a high concentration of sucrose (1–3 M) was developed using levansucrase prepared fromLeuconostoc mesenteroides B-1355C. The degree of polymerization of oligosaccharides synthesized according to the present method ranged from 2 to over 15. The synthesized BFOS were stable at a pH ranges of 2 to 4 under 120°C. The percentage of BFOS in the reaction digest was 95.7% (excluding monosaccharides; 4.3% was levan). BFOS reduced the insoluble glucan formation byStreptococcus sobrinus on the surfaces of glass vials or stainless steel wires in the presence of sucrose. They also reduced the growth and acid productions ofS. sobrinus. Oligosaccharides can be used as sweeteners for foods such as beverages requiring thermo-and acid-stable properties and as potential inhibitors of dental caries. The first two authors contributed equally to this work.     

稻、麦根系H~ 的分泌与介质磷水平的关系

水稻、小麦根系H~ 的分泌量随供磷水平的降低而增加,并存在明显的昼夜变化。在自然光照下H~ 分泌量随光强度增加而增多,同时强光比黑暗时H~ 分泌对磷供应水平更为敏感。磷供应不足还诱导水稻根系柠檬酸分泌量增加,而苹果酸则差异不明显。难溶性磷的溶解率与根系H~ 和柠檬酸分泌所导致的根际pH下降有密切联系。因此,在有效磷不足的条件下可明显提高稻、麦根际土壤中难溶性磷的利用率,其中丰产型小麦和粳稻品种对土壤中磷利用的根际效应更为显著。     

Incorporation of kaempferol 3-O-glucoside into the cell walls of Norway spruce needles

¹⁴C-Labelled CO₂ fed to young Norway spruce (Picea abies [L.] Karst.) twigs was rapidly incorporated into kaempferol 3-O-glucoside (astragalin) of the needles. The patterns of the time course of total (per needle weight) and specific radioactivity (per amount of compound) of soluble and insoluble (cell wall-bound) astragalin indicate its transport from a soluble pool within the protoplast to an extraprotoplastic cell wall-bound pool within the needle. This conclusion is supported by measurements of the distribution of radioactivity between the aglycone (kaempferol) and the sugar part (glucose) of the molecule after various chase periods as well as by control experiments to determine the localization of [¹⁴C]astragalin in the cell wall preparations.This work was supported by the Deutsche Forschungsgemeinschaft (Schwerpunktprogramm Physiologie der Bäume) and by the Fonds der Chemischen Industrie. We express our special thanks to J. Willenbrink and T. Schatten (Botanisches Institut, Köln, FRG) for advice and help in the ¹⁴CO₂-application experiments. We also thank H. Grisebach (Biologisches Institut II, Freiburg, FRG) for drawing our attention to the work of G. Brandner.