Synthesis of daunosamine-containing disaccharides

Treatment of 2,3,6-trideoxy-1,4-di-O-(p-nitrobenzoyl)-3-(trifluoroacetamido)-l-lyxo-hexopyranose (1) with benzyl 2,3-dideoxy-d-glycero-pentopyranoside and p-toluenesulfonic acid gave a mixture of benzyl 2,3,6-trideoxy-4-O-p-nitrobenzoyl-3- (trifluoroacetamido)-l-lyxo-hexopyranoside (49%) and benzyl 2,3-dideoxy-4-O-[2,3,6-trideoxy-4-O-(p-nitrobenzoyl)-3-(trifluoroacetamido)-α-l-lyxo-hexopyranosyl]-d-glycero-pentopyranoside (4, 20 %). The structure of the disaccharide 4 was confirmed by a detailed, mass-spectrometric analysis in three modes, namely, negative- and positive-ion, chemical ionization, and electron impact. Similar treatment of the bis(p-nitrobenzoate) 1 with ethyl 2,3-dideoxy-d-glycero-pentopyranoside gave the ethyl glycoside and the desired disaccharide, showing that the transglycosylation is not restricted to benzyl glycosides. Removal of the p-nitrobenzoyl and the benzyl groups from 4 gave the disaccharide 2,3-dideoxy-4-O-(2,3,6-trideoxy-3-trifluoroacetamido-α-l-lyxo-hexopyranosyl)-d-glycero-pentopyranose.     

Synthesis of 7-(tetrahydropyran-2-yl)- and 7-(4-acetoxytetrahydropyran-2-yl)-ε-rhodomycinone and 7-(tetrahydropyran-2-yl)-ε-pyrromycinone

The ¹³C.n.m.r spectra of water-soluble and -insoluble glucans synthesized by enzymes isolated from six strains of Streptococcus mutans are interpreted. The glucans are shown to be composed primarily of α(1→3)- and α-(1→6)-linked glucosyl residues, and the relative abundance of each linkage is estimated from peak areas. Treatment of water-insoluble glucans with dextranase is found to result in water-soluble and -insoluble products, the former enriched in α-(1→6)-linkages and the latter in α-(1→3)-linkages. The structural conclusions arrived at by ¹³C-n.m.r. spectroscopy are consistent with data from methylation analysis and ¹H-n.m.r. spectroscopy.     

Studies of the species barrier between Drosophila subobscura and D. madeirensis V: the importance of sex-linked inversion in preserving species identity

The X chromosome is known to exert a disproportionately large effect on characters related to post-zygotic reproductive isolation. There is also growing evidence about the important role of the chromosomal regions with reduced recombination (such as inversions) in maintaining the identity of closely related species. Using molecular markers, we examine the effect of different regions of the X chromosome on determination of hybrid traits (viability, testes size, sperm motility and morphological anomalies) in hybrid males between Drosophila madeirensis and Drosophila subobscura. The preponderant effect of a region localized inside the A2 inversion in the X chromosome in all hybrid traits is identified. Other marked regions exert a weaker influence or only influence some of the hybrid trait. Our results confirm the crucial role of sex-linked chromosomal inversion in preserving the identity of species with incomplete reproductive isolation. The specific genomic make-up of parental lines used to perform crosses has a great effect on hybrid fitness.     

The effect of high temperature on the kinetics of lipopolysaccharide (LPS)-induced human monocytes activity in vitro

Human peripheral blood monocytes were stimulated with lipopolysaccharide at different temperatures (34, 37 and 40 °C) and TNF-α, IL-1β and NO production was measured. Levels of TNF-α mRNA and IL-1β mRNA were measured by RT-PCR. Phagocytic activity of LPS-stimulated monocytes in terms of bacterial uptake and intracellular bacterial killing was checked at different conditions in vitro. Early elevation of TNF-α, IL-1β and NO production was found in LPS-stimulated monocytes that incubated at 40 °C followed by cells that incubated at 37 °C and lowest level was detected at 34 °C. Similar results were observed in the phagocytic activity. Expression of TNF-α mRNA and IL-1β mRNA was observed as early as 30 min post exposure to LPS in all studied temperatures and these, decreased sharply after 12 h post exposure to LPS in LPS-stimulated monocytes that incubated at 40 °C only. This report describes the striking effects of incubation temperature on activity of LPS-stimulated monocytes.     

Draft genome sequence of the volcano-inhabiting thermoacidophilic methanotroph Methylacidiphilum fumariolicum strain SolV

The draft genome of Methylacidiphilum fumariolicum SolV, a thermoacidophilic methanotroph of the phylum Verrucomicrobia, is presented. Annotation revealed pathways for one-carbon, nitrogen, and hydrogen catabolism and respiration together with central metabolic pathways. The genome encodes three orthologues of particulate methane monooxygenases. Sequencing of this genome will help in the understanding of methane cycling in volcanic environments.     

Differential inflammatory response to inhaled lipopolysaccharide targeted either to the airways or the alveoli in man

Endotoxin (Lipopolysaccharide, LPS) is a potent inducer of inflammation and there is various LPS contamination in the environment, being a trigger of lung diseases and exacerbation. The objective of this study was to assess the time course of inflammation and the sensitivities of the airways and alveoli to targeted LPS inhalation in order to understand the role of LPS challenge in airway disease.In healthy volunteers without any bronchial hyperresponsiveness we targeted sequentially 1, 5 and 20 μg LPS to the airways and 5 μg LPS to the alveoli using controlled aerosol bolus inhalation. Inflammatory parameters were assessed during a 72 h time period. LPS deposited in the airways induced dose dependent systemic responses with increases of blood neutrophils (peaking at 6 h), Interleukin-6 (peaking at 6 h), body temperature (peaking at 12 h), and CRP (peaking at 24 h). 5 μg LPS targeted to the alveoli caused significantly stronger effects compared to 5 μg airway LPS deposition. Local responses were studied by measuring lung function (FEV(1)) and reactive oxygen production, assessed by hydrogen peroxide (H(2)O(2)) in fractionated exhaled breath condensate (EBC). FEV(1) showed a dose dependent decline, with lowest values at 12 h post LPS challenge. There was a significant 2-fold H(2)O(2) induction in airway-EBC at 2 h post LPS inhalation. Alveolar LPS targeting resulted in the induction of very low levels of EBC-H(2)O(2).Targeting LPS to the alveoli leads to stronger systemic responses compared to airway LPS targeting. Targeted LPS inhalation may provide a novel model of airway inflammation for studying the role of LPS contamination of air pollution in lung diseases, exacerbation and anti-inflammatory drugs.     

Modeling the behavior of human induced pluripotent stem cells seeded on melt electrospun scaffolds

Background

Human induced pluripotent stem cells (hiPSCs) can form any tissue found in the body, making them attractive for regenerative medicine applications. Seeding hiPSC aggregates into biomaterial scaffolds can control their differentiation into specific tissue types. Here we develop and analyze a mathematical model of hiPSC aggregate behavior when seeded on melt electrospun scaffolds with defined topography.

Results

We used ordinary differential equations to model the different cellular populations (stem, progenitor, differentiated) present in our scaffolds based on experimental results and published literature. Our model successfully captures qualitative features of the cellular dynamics observed experimentally. We determined the optimal parameter sets to maximize specific cellular populations experimentally, showing that a physiologic oxygen level (～?5%) increases the number of neural progenitors and differentiated neurons compared to atmospheric oxygen levels (～?21%) and a scaffold porosity of ～?63% maximizes aggregate size.

Conclusions

Our mathematical model determined the key factors controlling hiPSC behavior on melt electrospun scaffolds, enabling optimization of experimental parameters.

     

Genetic exchange versus genetic differentiation in a medium-sized inversion of Drosophila: the A2/Ast arrangements of Drosophila subobscura

Chromosomal inversion polymorphism affects nucleotide variation at loci associated with inversions. In Drosophila subobscura, a species with a rich chromosomal inversion polymorphism and the largest recombinational map so far reported in the Drosophila genus, extensive genetic structure of nucleotide variation was detected in the segment affected by the O(3) inversion, a moderately sized inversion at Muller's element E. Indeed, a strong genetic differentiation all over O(3) and no evidence of a higher genetic exchange in the center of the inversion than at breakpoints were detected. In order to ascertain, whether other polymorphic and differently sized inversions of D. subobscura also exhibited a strong genetic structure, nucleotide variation in 5 gene regions (P236, P275, P150, Sxl, and P125) located along the A(2) inversion was analyzed in A(st) and A(2) chromosomes of D. subobscura. A(2) is a medium-sized inversion at Muller's element A and forms a single inversion loop in heterokaryotypes. The lower level of variation in A(2) relative to A(st) and the significant excess of low-frequency variants at polymorphic sites indicate that nucleotide variation at A(2) is not at mutation-drift equilibrium. The closest region to an inversion breakpoint, P236, exhibits the highest level of genetic differentiation (F(ST)) and of linkage disequilibrium (LD) between arrangements and variants at nucleotide polymorphic sites. The remaining 4 regions show a higher level of genetic exchange between A(2) and A(st) chromosomes than P236, as revealed by F(ST) and LD estimates. However, significant genetic differentiation between the A(st) and A(2) arrangements was detected not only at P236 but also in the other 4 regions separated from the nearest breakpoint by 1.2-2.9 Mb. Therefore, the extent of genetic exchange between arrangements has not been high enough to homogenize nucleotide variation in the center of the A(2) inversion. A(2) can be considered a typical successful inversion of D. subobscura according to its relative length. Chromosomal inversion polymorphism of D. subobscura might thus cause the genome of this species to be highly structured and to harbor different gene pools that might contribute to maintain adaptations to particular environments.     

Immunoassay method to check the flagellin mediated binding of stenotrophomonas maltophilia to polystyrene

Plate count and spectrophotometric methods have been used to asses the ability of an organism to attach to different surfaces and form biofilms. In the present study we report a highly sensitive, specific and quick method to check the role of flagellin in bacterial adhesion to polystyrene. Flagellin from Stenotrophomonas maltophilia showed high affinity for polystyrene (P < 0.05), which decreased on pretreatment offlagellin with anti-flagellin in a dilution dependent manner. In an enzyme immunoassay format a positive correlation was detected between the anti-flagellin dilutions and flagellin attachment to polystyrene (correlation coefficient +0.860155). These evidences conclusively prove the involvement of flagella in the adhesion ofS. maltophilia to polystyrene surface and enzyme immunoassay, a quick and reliable method to check this phenomenon.     

Source of Copper May Have Regressive Effects on Serum Cholesterol and Urea Nitrogen Among Male Fattening Lambs

An experiment was conducted to determine the effect of dietary copper (Cu) on mineral profile, hematological parameters, and lipid metabolism in lambs. Eighteen Zandi male lambs (approximately 3 months of age; 17.53?±?1.6 kg of body weight) were housed in individual pens and were assigned randomly to one of three treatments. Treatments consisted of (1) control (no supplemental Cu), (2) 10 mg Cu/kg dry matter (DM) from copper sulfate (CuS), and (3) 10 mg Cu/kg DM from Cu proteinate (CuP). The Cu concentration was 8.2 mg/kg DM in the basal diet. Blood was sampled from the jugular vein at the beginning of the study (enrollment, before feeding Cu supplement) and at days 25, 50, and 70 of experiment. The amounts of total serum glucose, urea nitrogen, calcium, phosphorus, iron, copper, zinc, and lipids and hematological parameters were measured. Average daily gain and feed efficiency were improved (P?<?0.05) with Cu supplementation and were better for the lambs fed diet supplemented with CuP. The concentrations of serum Ca, P, and Zn were not affected by source of Cu in the diet. However, Fe concentration was lower (P?<?0.01) in the Cu-supplemented groups. Experimental treatment had no significant effects on the hematological parameters. The serum glucose concentration was not affected by treatments. However, the urea nitrogen concentrations were significantly affected (P?<?0.05) by added Cu and was lower for CuP group as compared to the lambs in the CuS and control groups. Addition of Cu had no influence (P?>?0.05) on the serum triglyceride concentration, but lambs fed with CuP supplement had lower (P?<?0.05) serum cholesterol than the CuS and control animals. These results indicated that CuP supplemented at 10 mg/kg DM improved gain and enhanced the efficiency of nitrogen in male lambs.