A combined small‐angle X‐ray and neutron scattering study of the structure of purified soluble gastrointestinal mucins

The structures of purified soluble porcine gastric (Muc5ac) and duodenal (Muc2) mucin solutions at neutral and acidic pH were examined using small‐angle X‐ray scattering and small‐angle neutron scattering experiments. We provide evidence for the morphology of the network above the semidilute overlap concentration and above the entanglement concentration. Furthermore, we investigated the gelation of both types of mucin solutions in response to a reduction in pH, where we observed the formation of large‐scale heterogeneities within the polymer solutions, typical of microphase‐separated gels. The concentration dependence of the inhomogeneity length scale (Ξ) and the amplitude of the excess scattering intensity [I_ex(0)] are consistent with previously studied gelled synthetic polymeric systems. The persistence lengths of the chains were found to be similar for both Muc5ac and Muc2 from Kratky plots of the neutron data (8 ± 2 nm). © 2014 Wiley Periodicals, Inc. Biopolymers 101: 1154–1164, 2014.     

The evolution of intramitochondriality in Midichloria bacteria

Midichloria spp. are intracellular bacterial symbionts of ticks. Representatives of this genus colonise mitochondria in the cells of their hosts. To shed light on this unique interaction we evaluated the presence of an intramitochondrial localization for three Midichloria in the respective tick host species and generated eight high-quality draft genomes and one closed genome, showing that this trait is non-monophyletic, either due to losses or multiple acquisitions. Comparative genomics supports the first hypothesis, as the genomes of non-mitochondrial symbionts are reduced subsets of those capable of colonising the organelles. We detect genomic signatures of mitochondrial tropism, including the differential presence of type IV secretion system and flagellum, which could allow the secretion of unique effectors and/or direct interaction with mitochondria. Other genes, including adhesion molecules, proteins involved in actin polymerisation, cell wall and outer membrane proteins, are only present in mitochondrial symbionts. The bacteria could use these to manipulate host structures, including mitochondrial membranes, to fuse with the organelles or manipulate the mitochondrial network.     

Double Stereodifferentiation in the Asymmetric Dihydroxylation of Optically Active Olefins

A study of the stereochemical control on the asymmetric dihydroxylation of the double bond of optically active vinyl epoxides and their derivatives (bromo derivatives, azido derivatives, and vinyl aziridines) was carried out and the obtained results are herein reported. The most interesting results were obtained on trans α,β‐unsaturated epoxy esters, which were successfully converted with a diastereomeric ratio >80% into the corresponding diols using either the matched or the mismatched conditions, depending on the ligand used. Unprotected bromo derivatives and unprotected aziridines did not afford significant results, while for the protected bromo derivatives, azido derivatives, and N‐Boc protected aziridines the matched conditions led to a diastereomeric ratio >95%. Chirality 28:387–393, 2016. © 2016 Wiley Periodicals, Inc.     

Comparison of estrogens and estrogen metabolites in human breast tissue and urine

Background  

An important aspect of the link between estrogen and breast cancer is whether urinary estrogen levels are representative of the intra-tissue levels of bioavailable estrogens.     

Anti-amnesic properties of (±)-PPCC, a novel sigma receptor ligand, on cognitive dysfunction induced by selective cholinergic lesion in rats

Previous studies have reported that selective sigma-1 agonists may improve cognitive abilities in experimental animals possibly via a cholinergic mechanism. However, the issue of a direct action on to sigma-1 receptors in memory-related brain areas has been much less investigated. The newly synthetised compound methyl(1 R ,2 S /1 S ,2 R )-2-[4-hydroxy-4-phenylpiperidin-1-yl)methyl]-1-(4-methylphenyl) cyclopropanecarboxylate [(±)-PPCC] has recently been shown to possess high affinity for the sigma-1 receptor where it specifically acts as an agonist. Here, the functional effects of (±)-PPCC were investigated in rat models of mild or severe cognitive dysfunction based on a sub-total (≤ 70–80%) or complete (≥ 90–95%) central cholinergic depletion induced by different doses of the selective immunotoxin 192 IgG-saporin injected intraventricularly. At 5–6 weeks post-surgery, the lesioned animals exhibited dose-dependent deficits in reference memory, as assessed using the Morris water maze task, whereas working memory abilities, evaluated using the radial arm water maze task, appeared equally impaired in the two dose groups. Daily treatment with (±)-PPCC significantly improved both reference and working memory performance in all lesioned animals but it did not affect intact or sham-lesioned subjects. In a separate test, treatment with (±)-PPCC reversed the learning deficits induced by the muscarinic receptor antagonist atropine sulphate in both control and mild-lesioned rats. The effect was blocked in lesioned, but not normal animals by pre-treatment with the sigma-1 antagonist N -[2-(3,4-dichlorophenyl)ethyl]- N -methyl-2-(dimethylamino)ethylamine. The results suggest that (±)-PPCC may efficiently ameliorate perturbed cognitive abilities, and that these anti-amnesic effects most probably occur via a direct interaction of the compound with sigma-1 receptors.     

Small area estimation for semicontinuous skewed spatial data: An application to the grape wine production in Tuscany

Linear‐mixed models are frequently used to obtain model‐based estimators in small area estimation (SAE) problems. Such models, however, are not suitable when the target variable exhibits a point mass at zero, a highly skewed distribution of the nonzero values and a strong spatial structure. In this paper, a SAE approach for dealing with such variables is suggested. We propose a two‐part random effects SAE model that includes a correlation structure on the area random effects that appears in the two parts and incorporates a bivariate smooth function of the geographical coordinates of units. To account for the skewness of the distribution of the positive values of the response variable, a Gamma model is adopted. To fit the model, to get small area estimates and to evaluate their precision, a hierarchical Bayesian approach is used. The study is motivated by a real SAE problem. We focus on estimation of the per‐farm average grape wine production in Tuscany, at subregional level, using the Farm Structure Survey data. Results from this real data application and those obtained by a model‐based simulation experiment show a satisfactory performance of the suggested SAE approach.     

Molecular ecology and phylogenetics of the water beetle genus Ochthebius revealed multiple independent shifts to marine rockpools lifestyle

Marine rockpools represent a dynamic ecosystem where inhabiting species usually suffer changeable conditions, with consequent phenomena of local populations’ size expansions and reductions. Nevertheless, a few specialized insect groups are known to live in marine rockpools, and among them, several species belong to the water beetle family Hydraenidae. Three groups of Ochthebius sensu lato (s.l.) live in fact in marine rockpools: the putative subgenus Calobius, the former subgenus Cobalius (both mostly Mediterranean–Macaronesian) and two species of the O. capicola group from South Africa. In this work, we performed a molecular phylogeny of Ochthebius s.l., running molecular clocks, aiming to address the following questions: Are these three groups related? Which is their position within Ochthebius s.l.? How many different times and in how many lineages of Ochthebius s.l. a shift from inland waters to marine rockpools environments happened? Is the current taxonomic status of these three groups supported by genetics? We found that Calobius, Cobalius and the O. capicola group represent three distinct groups, with no sister relationships, suggesting that a shift from fresh/brackish waters to marine rockpools happened independently at least three different times along the diversification of the genus. Cobalius represents an effective separate subgenus, whereas such a rank is not supported by molecular data for Calobius, which represents a monophyletic clade within the nominal subgenus Ochthebius sensu stricto (s.str.). However, as Calobius is monophyletic and characterized by strongly peculiar and distinguishing morphology, we suggest referring to this group as the ‘Calobius’ lineage. Three Mediterranean taxa within this lineage represent likely valid new species, to be described soon. In the same way, the taxonomy of Cobalius should be revised, with two previously formally recognized species found to be paraphyletic, and the possible presence of two additional cryptic species.