Shared and Distinct Features of Human Milk and Infant Stool Viromes.

Infants acquire many of their microbes from their mothers during the birth process. The acquisition of these microbes is believed to be critical in the development of the infant immune system. Bacteria also are transmitted to the infant through breastfeeding, and help to form the microbiome of the infant gastrointestinal (GI) tract; it is unknown whether viruses in human milk serve to establish an infant GI virome. We examined the virome contents of milk and infant stool in a cohort of mother-infant pairs to discern whether milk viruses colonize the infant GI tract. We observed greater viral alpha diversity in milk than in infant stool, similar to the trend we found for bacterial communities from both sites. When comparing beta diversity, viral communities were mostly distinguishable between milk and infant stool, but each was quite distinct from adult stool, urine, and salivary viromes. There were significant differences in viral families in the infant stool (abundant bacteriophages from the family Siphoviridae) compared to milk (abundant bacteriophages from the family Myoviridae), which may reflect significant differences in the bacterial families identified from both sites. Despite the differences in viral taxonomy, we identified a significant number of shared viruses in the milk and stool from all mother-infant pairs. Because of the significant proportion of bacteriophages transmitted in these mother-infant pairs, we believe the transmission of milk phages to the infant GI tract may help to shape the infant GI microbiome

Validity and worth in the science curriculum: learning school science outside the laboratory

It is widely acknowledged that there are problems with school science in many developed countries of the world. Such problems manifest themselves in a progressive decline in pupil enthusiasm for school science across the secondary age range and the fact that fewer students are choosing to study the physical sciences at higher levels and as careers. Responses to these developments have included proposals to reform the curriculum, pedagogy and the nature of pupil discussion in science lessons. We support such changes but argue from a consideration of the aims of science education that secondary school science is too rooted in the science laboratory; substantially greater use needs to be made of out-of-school sites for the teaching of science. Such usage should result in a school science education that is more valid and more motivating and is better at fulfilling defensible aims of school science education. Our contention is that laboratory-based school science teaching needs to be complemented by out-of-school science learning that draws on the actual world (e.g. through fieldtrips), the presented world (e.g. in science centres, botanic gardens, zoos and science museums) and the virtual worlds that are increasingly available through information and communications technologies (ICT)

First Measurement of the Transverse Spin Asymmetries of the Deuteron in Semi-Inclusive Deep Inelastic Scattering

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6-LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.Comment: 6 pages, 2 figure

Measurement of the Spin Structure of the Deuteron in the DIS Region

We present a new measurement of the longitudinal spin asymmetry A_1^d and the spin-dependent structure function g_1^d of the deuteron in the range 1 GeV^2 < Q^2 < 100 GeV^2 and 0.004< x <0.7. The data were obtained by the COMPASS experiment at CERN using a 160 GeV polarised muon beam and a large polarised 6-LiD target. The results are in agreement with those from previous experiments and improve considerably the statistical accuracy in the region 0.004 < x < 0.03.Comment: 10 pages, 6 figures, subm. to PLB, revised: author list, Fig. 4, details adde

Ruthenium-thymine acetate binding modes: Experimental and theoretical studies

Ruthenium complexes have proved to exhibit antineoplastic activity, related to the interaction of the metal ion with DNA. In this context, synthetic and theoretical studies on ruthenium binding modes of thymine acetate (THAc) have been focused to shed light on the structure-activity relationship. This report deals with the reaction between dihydride ruthenium mer-[Ru(H)2(CO)(PPh3)3], 1 and the thymine acetic acid (THAcOH) selected as model for nucleobase derivatives. The reaction in refluxing toluene between 1 and THAcOH excess, by H2 release affords the double coordinating species k1-(O)THAc-, k2-(O,O)THAc-[Ru(CO)(PPh3)2], 2. The X-ray crystal structure confirms a simultaneous monohapto, dihapto- THAc coordination in a reciprocal facial disposition. Stepwise additions of THAcOH allowed to intercept the monohapto mer-k1(O)THAc-Ru(CO)H(PPh3)3] 3 and dihapto trans(P,P)-k2(O,O)THAc-[Ru(CO)H(PPh3)2] 4 species. Nuclear magnetic resonance (NMR) studies, associated with DFT (Density Function Theory)-calculations energies and analogous reactions with acetic acid, supported the proposed reaction path. As evidenced by the crystal supramolecular hydrogen-binding packing and 1H NMR spectra, metal coordination seems to play a pivotal role in stabilizing the minor [(N=C(OH)] lactim tautomers, which may promote mismatching to DNA nucleobase pairs as a clue for its anticancer activity

Ru-Controlled Thymine Tautomerization Frozen by a k1(O)-, k2(N,O)-Metallacycle: An Experimental and Theoretical Approach

The reaction of mer-(Ru(H)2(CO)(PPh3)3) (1) with one equivalent of thymine acetic acid (THAcH) unexpectedly produces the macrocyclic dimer k1(O), k2(N,O)-(Ru(CO)(PPh3)2THAc)2 (4) and, concomitantly, the doubly coordinated species k1(O), k2(O,O)-(Ru(CO)(PPh3)2THAc) (5). The reaction promptly forms a complicated mixture of Ru-coordinated mononuclear species. With the aim of shedding some light in this context, two plausible reaction paths were proposed by attributing the isolated or spectroscopically intercepted intermediates on the basis of DFT-calculated energetic considerations. The cleavage of the sterically demanding equatorial phosphine in the mer-species releases enough energy to enable self-aggregation, producing the stable, symmetric 14-membered binuclear macrocycle of 4. The k1-acetate iminol (C=N-OH) unit of the mer-tautomer k1(O)-(Ru(CO)(PPh3)2(THAc)) (2) likely exhibits a stronger nucleophilic aptitude than the prevalent N(H)-C(O) amido species, thus accomplishing extra stabilization through concomitant k2(N,O)-thymine heteroleptic side-chelation. Furthermore, both the ESI-Ms and IR simulation spectra validated the related dimeric arrangement in solution, in agreement with the X-ray determination of the structure. The latter showed tautomerization to the iminol form. The 1H NMR spectra in chlorinated solvents of the kinetic mixture showed the simultaneous presence of 4 and the doubly coordinated 5, in rather similar amounts. THAcH added in excess preferentially reacts with 2 or trans-k2(O,O)-(RuH(CO)(PPh3)2THAc) (3) rather than attacking the starting Complex 1, promptly forming the species of 5. The proposed reaction paths were inferred by spectroscopically monitoring the intermediate species, for which the results were strongly dependent on the of conditions the reaction (stoichiometry, solvent polarity, time, and the concentration of the mixture). The selected mechanism proved to be more reliable, due to the final dimeric product stereochemistry