Inhibition of iodine organification and regulation of follicular size in rat thyroid tissue in vitro

The factors mediating the accumulation of thyroglobulin are of great importance to the understanding of the pathogenesis of human and experimentally induced colloid goiters. To elucidate further the underlying cellular mechanism, thyroid fragments from newborn rats were incorporated into semisolid alginate beads and were cultured as three-dimensional organoids for up to 21 d. In five parallel cultures, the medium contained either no supplements (group A), Nal (group B), thyroid-stimulating hormone (TSH) (group C), Nal plus TSH in the same concentrations as B and C (group D), or Nal and TSH (as in group D) plus methimazole (MMI, group E). The thyroid organoids maintained morphological intergrity, functional activity, and ability to proliferate in vitro. Addition of iodine to the cultures significantly increased mean (±SEM) follicular diameters from 19.5±0.7 μm in controls to 33.9±2.2 μm (p<0.0001) when Nal was added alone (group B), and 30.4±1.7 μm (p<0.0001) when combined with TSH (group D). The effect of Nal on follicular size was abolished by MMI (group E, follicular diameter 23.5±1.3 μm). The results presented support the recent finding, using a rat colloid goiter model, that not only TSH but also iodine organification or its inhibition are important factors in modulating follicular morpholog

Stacking disorder: the hexagonal polymorph of tris(bicyclo[2.1.1]hexeno)benzene and related examples

X-ray diffractograms of tris(bicyclo[2.1.1]hexeno)benzene, crystallized at the interface between a benzene solution and a layer of acetonitrile, show hexagonal symmetry and streaks of diffuse scattering along c*. The heavily faulted layer stacking is analyzed qualitatively and quantitatively in terms of a systematic protocol. This protocol requires partitioning the crystal structure into layers in such a way that pairs of adjacent layers may be stacked in different, but geometrically equivalent ways, which are dictated by the layer group symmetry. This approach is shown to provide a consistent alternative for analysis of a number of related cases provided the layers are defined on the basis of geometrical criteria rather than chemical intuitio

Identifying functional groups of phytoplankton using data from three lakes of different trophic state

Abstract.: There is tremendous diversity in species of phytoplankton. Yet one may expect some degree of commonality in the response of similar species to similar conditions. Functional groups are those sets of species that respond similarly to environmental conditions because they have similar properties. The identification of such functional groups can assist model-based prediction of the abundance of phytoplankton as a function of time, space, and environmental conditions. Functional groups can also assist limnologists in the analysis and presentation of field data. We identified functional groups of phytoplankton using a combination of prior knowledge (based on taxonomic divisions and measurable properties) and statistical cluster analysis of long-term, species-level data from three Swiss lakes of different trophic state. For this task, we used the taxonomic division as the basic unit of analysis. Each taxonomic group was subdivided into several further groups by analysing the occurrence pattern of each species of the group and grouping together species with similar patterns. The reasons for the occurrence pattern for each species within a group were then analysed based on the main properties of the species. The results of this analysis were used to merge groups that had similar occurrence for similar reasons across taxonomic boundaries. Groups with different occurrence patterns but similar properties were also merged. This led to suggestions for functional groups at multiple levels of aggregation. The resulting groups were used in a subsequent study for modelling phytoplankton in the three lakes used for this analysis. The general methodology of combining prior knowledge on properties with empirical evidence on occurrence should be useful for finding functional groups of phytoplankton in other lakes as well. Comparisons of studies across lakes can then contribute to the identification of universal functional groups of phytoplankton applicable to a broad class of water

Temporary collapse of the Daphnia population in turbid and ultra-oligotrophic Lake Brienz

Abstract.: The cyclical parthenogen Daphnia is a key species in aquatic food webs. Its abundance is influenced by environmental factors like food quantity and quality, predation, diseases, temperature and washout by discharge. In ultra-oligotrophic Lake Brienz (Switzerland), which is turbid from suspended glacial material, Daphnia density has continuously decreased since the 1990 s. In spring and summer 1999, during and after a severe flood, Daphnia density was below detection level, but the population recovered the following year. Simultaneously, a drastic two-year decline occurred in the yield of whitefish (Coregonus sp.), which mainly feed on Daphnia. Several hypotheses were tested to explain the collapse of the Daphnia population: a negative effect of the suspended particles, a covering of the diapausing eggs by sediment, and a combined washout/temperature effect. A direct negative effect of the particles and covering of diapausing eggs could be excluded. According to model calculations, the spring growth of the Daphnia population could not compensate the washout losses, as it was limited by poor food conditions due to re-oligotrophication and reduced by extraordinarily low water temperatures. Moreover, ephippia abundance analysed from sediment cores was consistent with the process of eutrophication and re-oligotrophication and indicated that daphnids did not persist in the lake in the period before eutrophication (until 1955). Like most peri-alpine lakes in Europe, Lake Brienz has returned to its natural ultra-oligotrophic state and is now unable to support a large Daphnia population and fishing yiel

Comments on `Hydrogen bonds in crystalline D-alanine: diffraction and spectroscopic evidence for differences between enantiomers'

The recent paper by Belo, Pereira, Freire, Argyriou, Eckert & Bordallo [(2018), IUCrJ, 5, 6–12] reports observations that may lead one to think of very strong and visible consequences of the parity-violation energy difference between enantiomers of a molecule, namely alanine. If proved, this claim would have an enormous impact for research in structural chemistry. However, alternative, more realistic, explanations of their experiments have not been ruled out by the authors. Moreover, the theoretical calculations carried out to support the hypothesis are unable to differentiate between enantiomers (molecules or crystals). Therefore, the conclusions drawn by Belo et al. (2018) are deemed inappropriate as the data presented do not contain sufficient information to reach such a conclusion

Novel Host-Guest Structures of 2,4,6- Tris (4-Halophenoxy)-1,3,5-Triazines(XPOT): Inclusion of C60 and Pyridine

The crystal structures of two halophenoxytriazine host-guest compounds are reported and discussed. They feature inclusion of C60 into cages of 2,4,6-tris(4-iodophenoxy)-1,3,5-triazine [IPOT, hexagonal, P63/m, a=16.367(2)Å, c=20.661(4)Å, V=4793.1(13)Å3, Z=2] and of pyridine6-clusters into cages of 2,4,6-tris(4-bromophenoxy)-1,3,5-triazine (BrPOT, rhombohedral, R $$\bar{3}$$ , a=15.5186(8)Å, c=39.521(3)Å, V=8242.7(8)Å3, Z=6). The stackings of the threefold symmetric layers of XPOT host molecules are different from each other and from those of all previously reported XPOT inclusion compounds (X: Cl, Br, I). Graphical Abstract: The new compounds IPOT3·C60 and BrPOT2·py3, represent new packing types in the family of threefold symmetric XPOT inclusion compounds (XPOT=2,4,6-tris(4-halophenoxy)-1,3,5-triazine; X=Cl, Br, I

Distinction of disorder, classical and quantum vibrational contributions to atomic mean-square amplitudes in dielectric pentachloronitrobenzene

The solid-state molecular disorder of pentachloronitrobenzene (PCNB) and its role in causing anomalous dielectric properties are investigated. Normal coordinate analysis (NCA) of atomic mean-square displacement parameters (ADPs) is employed to distinguish disorder contributions from classical and quantum-mechanical vibrational contributions. The analysis relies on multitemperature (5-295 K) single-crystal neutron-diffraction data. Vibrational frequencies extracted from the temperature dependence of the ADPs are in good agreement with THz spectroscopic data. Aspects of the static disorder revealed by this work, primarily tilting and displacement of the molecules, are compared with corresponding results from previous, much more in-depth and time-consuming Monte Carlo simulations; their salient findings are reproduced by this work, demonstrating that the faster NCA approach provides reliable constraints for the interpretation of diffuse scattering. The dielectric properties of PCNB can thus be rationalized by an interpretation of the temperature-dependent ADPs in terms of thermal motion and molecular disorder. The use of atomic displacement parameters in the NCA approach is nonetheless hostage to reliable neutron data. The success of this study demonstrates that state-of-the-art single-crystal Laue neutron diffraction affords sufficiently fast the accurate data for this type of study. In general terms, the validation of this work opens up the field for numerous studies of solid-state molecular disorder in organic materials.Comment: Now published in Physical Review

Glycyl-L-alanine: A multi-temperature neutron study

Neutron diffraction data have been collected at 12, 50, 150 and 295 K for the dipeptide glycyl-L-alanine, C5H10N2O3, in order to obtain accurate positional and anisotropic displacement parameters for the H atoms. The values of these parameters serve as a benchmark for assessing the equivalent parameters obtained from a so-called Hirshfeld-atom refinement of X-ray diffraction data described elsewhere [Capelli et al. (2014). IUCrJ, 1, 361-379]. The flexibility of the glycyl-L-alanine mol­ecule in the solid and the hydrogen-bonding inter­actions as a function of temperature are also considered

Metabolomic Analyses of Plasma Reveals New Insights into Asphyxia and Resuscitation in Pigs

Currently, a limited range of biochemical tests for hypoxia are in clinical use. Early diagnostic and functional biomarkers that mirror cellular metabolism and recovery during resuscitation are lacking. We hypothesized that the quantification of metabolites after hypoxia and resuscitation would enable the detection of markers of hypoxia as well as markers enabling the monitoring and evaluation of resuscitation strategies.Hypoxemia of different durations was induced in newborn piglets before randomization for resuscitation with 21% or 100% oxygen for 15 min or prolonged hyperoxia. Metabolites were measured in plasma taken before and after hypoxia as well as after resuscitation. Lactate, pH and base deficit did not correlate with the duration of hypoxia. In contrast to these, we detected the ratios of alanine to branched chained amino acids (Ala/BCAA; R(2).adj = 0.58, q-value<0.001) and of glycine to BCAA (Gly/BCAA; R(2).adj = 0.45, q-value<0.005), which were highly correlated with the duration of hypoxia. Combinations of metabolites and ratios increased the correlation to R(2)adjust = 0.92. Reoxygenation with 100% oxygen delayed cellular metabolic recovery. Reoxygenation with different concentrations of oxygen reduced lactate levels to a similar extent. In contrast, metabolites of the Krebs cycle (which is directly linked to mitochondrial function) including alpha keto-glutarate, succinate and fumarate were significantly reduced at different rates depending on the resuscitation, showing a delay in recovery in the 100% reoxygenation groups. Additional metabolites showing different responses to reoxygenation include oxysterols and acylcarnitines (n = 8-11, q<0.001).This study provides a novel strategy and set of biomarkers. It provides biochemical in vivo data that resuscitation with 100% oxygen delays cellular recovery. In addition, the oxysterol increase raises concerns about the safety of 100% O(2) resuscitation. Our biomarkers can be used in a broad clinical setting for evaluation or the prediction of damage in conditions associated with low tissue oxygenation in both infancy and adulthood. These findings have to be validated in human trials

The receptor locus for Escherichia coli F4ab/F4ac in the pig maps distal to the MUC4 - LMLN region

Enterotoxigenic Escherichia coli (ETEC) with fimbriae of the F4 family are one of the major causes of diarrhea and death among neonatal and young piglets. Bacteria use the F4 fimbriae to adhere to specific receptors expressed on the surface of the enterocytes. F4 fimbriae exist in three different antigenic variants, F4ab, F4ac, and F4ad, of which F4ac is the most common. Resistance to ETEC F4ab/F4ac adhesion in pigs has been shown to be inherited as an autosomal recessive trait. In previous studies the ETEC F4ab/F4ac receptor locus (F4bcR) was mapped to the q41 region on pig chromosome 13. A polymorphism within an intron of the mucin 4 (MUC4) gene, which is one of the possible candidate genes located in this region, was shown earlier to cosegregate with the F4bcR alleles. Recently, we discovered a Large White boar from a Swiss experimental herd with a recombination between F4bcR and MUC4. A three-generation pedigree including 45 offspring was generated with the aim to use this recombination event to refine the localization of the F4bcR locus. All pigs were phenotyped using the microscopic adhesion test and genotyped for a total of 59 markers. The recombination event was mapped to a 220-kb region between a newly detected SNP in the leishmanolysin-like gene (LMLN g.15920) and SNP ALGA0072075. In this study the six SNPs ALGA0072075, ALGA0106330, MUC13-226, MUC13-813, DIA0000584, and MARC0006918 were in complete linkage disequilibrium with F4bcR. Based on this finding and earlier investigations, we suggest that the locus for F4bcR is located between the LMLN locus and microsatellite S028