Showing papers by "University of Göttingen published in 2004"

Scattered Data Approximation

Abstract: 1. Applications and motivations 2. Hear spaces and multivariate polynomials 3. Local polynomial reproduction 4. Moving least squares 5. Auxiliary tools from analysis and measure theory 6. Positive definite functions 7. Completely monotine functions 8. Conditionally positive definite functions 9. Compactly supported functions 10. Native spaces 11. Error estimates for radial basis function interpolation 12. Stability 13. Optimal recovery 14. Data structures 15. Numerical methods 16. Generalised interpolation 17. Interpolation on spheres and other manifolds.

Evaluated kinetic and photochemical data for atmospheric chemistry: Volume I - gas phase reactions of O x , HO x , NO x and SO x species

Abstract: . This article, the first in the series, presents kinetic and photochemical data evaluated by the IUPAC Subcommittee on GasKinetic Data Evaluation for Atmospheric Chemistry. It covers the gas phase and photochemical reactions of Ox, HOx, NOx and SOx species, which were last published in 1997, and were updated on the IUPAC website in late 2001. The article consists of a summary sheet, containing the recommended kinetic parameters for the evaluated reactions, and five appendices containing the data sheets, which provide information upon which the recommendations are made.

Depression as a risk factor for mortality in patients with coronary heart disease: a meta-analysis.

Abstract: Background Prospective studies on physically healthy subjects have shown an association between depression and the subsequent development of coronary heart disease (CHD). The relative risk in meta-analytic aggregation is 1.64 (confidence interval [CI], 1.29-2.08) for any CHD event. However, the adverse impact of depression on CHD patients has not yet been the subject of a meta-analysis. Objective To quantify the impact of depressive symptoms (eg, BDI, HADS) or depressive disorders (major depression) on cardiac or all-cause mortality. We analyzed the strength of the relationship, the time dependency, and the differences in studies using depressive symptoms or a clinical diagnosis as predictors of mortality. Method English and German language databases (Medline, PsycInfo, PSYNDEX) from 1980 to 2003 were searched for prospective cohort studies. Sixty-two publications were identified. The inclusion criteria were met by 29 publications reporting on 20 studies. A random model was used to estimate the combined overall effect as crude odds ratios (OR) or adjusted hazard ratios (HR [adj]). Results Depressive symptoms increase the risk of mortality in CHD patients. The risk of depressed patients dying in the 2 years after the initial assessment is two times higher than that of nondepressed patients (OR, 2.24; 1.37-3.60). This negative prognostic effect also remains in the long-term (OR, 1.78; 1.12-2.83) and after adjustment for other risk factors (HR [adj], 1.76; 1.27-2.43). The unfavorable impact of depressive disorders was reported for the most part in the form of crude odds ratios. Within the first 6 months, depressive disorders were found to have no significant effect on mortality (OR, 2.07; CI, 0.82-5.26). However, after 2 years, the risk is more than two times higher for CHD patients with clinical depression (OR, 2.61; 1.53-4.47). Only three studies reported adjusted hazard ratios for clinical depression and supported the results of the bivariate models. Conclusions Depressive symptoms and clinical depression have an unfavorable impact on mortality in CHD patients. The results are limited by heterogeneity of the results in the primary studies. There is no clear evidence whether self-report or clinical interview is the more precise predictor. Nevertheless, depression has to be considered a relevant risk factor in patients with CHD.

A distinct "side population" of cells with high drug efflux capacity in human tumor cells.

Abstract: A subset of stem cells, termed the “side population” (SP), has been identified in several tissues in mammalian species. These cells maintain a high efflux capability for antimitotic drugs. We have investigated whether functionally equivalent stem cells also may be detected in human cancers. We initially examined primary tumor cells from 23 patients with neuroblastoma and cell lines derived from a range of other tumors. A distinct SP was found in neuroblastoma cells from 15 of 23 patients (65%). The SP was capable of sustained expansion ex vivo and showed evidence for asymmetric division, generating both SP and non-SP progeny. These cells also expressed high levels of ABCG2 and ABCA3 transporter genes and had a greater capacity to expel cytotoxic drugs, such as mitoxantrone, resulting in better survival. A SP also was detected in breast cancer, lung cancer, and glioblastoma cell lines, suggesting that this phenotype defines a class of cancer stem cells with inherently high resistance to chemotherapeutic agents that should be targeted during the treatment of malignant disease.

Further characterisation of the 91500 zircon crystal

Abstract: This paper reports the results from a second characterisation of the 91500 zircon, including data from electron probe microanalysis, laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS), secondary ion mass spectrometry (SIMS) and laser fluorination analyses. The focus of this initiative was to establish the suitability of this large single zircon crystal for calibrating in situ analyses of the rare earth elements and oxygen isotopes, as well as to provide working values for key geochemical systems. In addition to extensive testing of the chemical and structural homogeneity of this sample, the occurrence of banding in 91500 in both backscattered electron and cathodoluminescence images is described in detail. Blind intercomparison data reported by both LA-ICP-MS and SIMS laboratories indicate that only small systematic differences exist between the data sets provided by these two techniques. Furthermore, the use of NIST SRM 610 glass as the calibrant for SIMS analyses was found to introduce little or no systematic error into the results for zircon. Based on both laser fluorination and SIMS data, zircon 91500 seems to be very well suited for calibrating in situ oxygen isotopic analyses.

AUGUSTUS: a web server for gene finding in eukaryotes

Abstract: We present a www server for AUGUSTUS, a novel software program for ab initio gene prediction in eukaryotic genomic sequences. Our method is based on a generalized Hidden Markov Model with a new method for modeling the intron length distribution. This method allows approximation of the true intron length distribution more accurately than do existing programs. For genomic sequence data from human and Drosophila melanogaster, the accuracy of AUGUSTUS is superior to existing gene-finding approaches. The advantage of our program becomes apparent especially for larger input sequences containing more than one gene. The server is available at http://augustus.gobics.de.

Axonal neuregulin-1 regulates myelin sheath thickness

Abstract: In the nervous system of vertebrates, myelination is essential for rapid and accurate impulse conduction. Myelin thickness depends on axon fiber size. We use mutant and transgenic mouse lines to show that axonal Neuregulin-1 (Nrg1) signals information about axon size to Schwann cells. Reduced Nrg1 expression causes hypomyelination and reduced nerve conduction velocity. Neuronal overexpression of Nrg1 induces hypermyelination and demonstrates that Nrg1 type III is the responsible isoform. We suggest a model by which myelin-forming Schwann cells integrate axonal Nrg1 signals as a biochemical measure of axon size.

Asymmetric Price Transmission: A Survey

Abstract: Asymmetric price transmission has been the subject of considerable attention in agricultural economics. It is not only important because it may point to gaps in economic theory, but also because its presence is often considered for policy purposes to be evidence of market failure. In this paper we survey the literature on asymmetric price transmission. A wide variety of often conflicting theories of, and empirical tests for, asymmetry co-exist in this literature. We classify the different types and causes of asymmetric price transmission and describe the econometric techniques used to quantify it. We also briefly review the results of empirical applications. Outstanding methodological problems and suggestions for future research are discussed. Our main conclusion is that the existing literature is far from being unified or conclusive, and that it has often been largely method-driven, with little attention devoted to theoretical underpinnings and the plausible interpretation of results. Hence, much interesting theoretical and empirical work remains to be done.

HKL2MAP: a graphical user interface for macromolecular phasing with SHELX programs

Abstract: One approach to phasing of macromolecular crystal structure is to exploit the small changes in diffracted intensities induced by the inclusion of heavy atoms, to alter the wavelength in the presence of anomalous scatterers, or to use a combination thereof. In the SHELX suite of crystallographic programs, the computations involved in the respective phasing procedures are divided into three steps: (i) extraction of structure factors representing the substructure of heavy atoms and/or anomalous scatterers only (SHELXC; Sheldrick, 2004), (ii) determination of the substructure (SHELXD; Schneider & Sheldrick, 2002), (iii) calculation of initial phases based on the knowledge of the substructure and improvement of these phases by density modi®cation (SHELXE; Sheldrick, 2002). A number of crystal structures have been solved using the combination of the programs mentioned above. However, in particular for the inexperienced user, the creation of correct input ®les and the interpretation of the intermediate results can be a major obstacle.

Pharmacogenetics of antidepressants and antipsychotics: the contribution of allelic variations to the phenotype of drug response

Abstract: Genetic factors contribute to the phenotype of drug response. We systematically analyzed all available pharmacogenetic data from Medline databases (1970-2003) on the impact that genetic polymorphisms have on positive and adverse reactions to antidepressants and antipsychotics. Additionally, dose adjustments that would compensate for genetically caused differences in blood concentrations were calculated. To study pharmacokinetic effects, data for 36 antidepressants were screened. We found that for 20 of those, data on polymorphic CYP2D6 or CYP2C19 were found and that in 14 drugs such genetic variation would require at least doubling of the dose in extensive metabolizers in comparison to poor metabolizers. Data for 38 antipsychotics were examined: for 13 of those CYP2D6 and CYP2C19 genotype was of relevance. To study the effects of genetic variability on pharmacodynamic pathways, we reviewed 80 clinical studies on polymorphisms in candidate genes, but those did not for the most part reveal significant associations between neurotransmitter receptor and transporter genotypes and therapy response or adverse drug reactions. In addition associations found in one study could not be replicated in other studies. For this reason, it is not yet possible to translate pharmacogenetic parameters fully into therapeutic recommendations. At present, antidepressant and antipsychotic drug responses can best be explained as the combinatorial outcome of complex systems that interact at multiple levels. In spite of these limitations, combinations of polymorphisms in pharmacokinetic and pharmacodynamic pathways of relevance might contribute to identify genotypes associated with best and worst responders and they may also identify susceptibility to adverse drug reactions.

European clinical guidelines for hyperkinetic disorder-first upgrade

Abstract: BACKGROUND: The validity of clinical guidelines changes over time, because new evidence-based knowledge and experience develop OBJECTIVE: Hence, the European clinical guidelines on hyperkinetic disorder from 1998 had to be evaluated and modified METHOD: Discussions at the European Network for Hyperkinetic Disorders (EUNETHYDIS) and iterative critique of each clinical analysis Guided by evidence-based information and based on evaluation (rather than metaanalysis) of the scientific evidence a group of child psychiatrists and psychologists from several European countries updated the guidelines of 1998 When reliable information is lacking the group gives a clinical consensus when it could be found among themselves RESULTS: The group presents here a set of recommendations for the conceptualization and management of hyperkinetic disorder and attention deficit/hyperactivity disorder (ADHD) CONCLUSION: A general scheme for practice in Europe could be provided, on behalf of the European Society for Child and Adolescent Psychiatry (ESCAP)

The Number of Alveoli in the Human Lung

Abstract: The number of alveoli is a key structural determinant of lung architecture. A design-based stereologic approach was used for the direct and unbiased estimation of alveolar number in the human lung. The principle is based on two-dimensional topology in three-dimensional space and is free of assumptions on the shape, size, or spatial orientation of alveoli. Alveolar number is estimated by counting their openings at the level of the free septal edges, where they form a two-dimensional network. Mathematically, the Euler number of this network is estimated using physical disectors at a light microscopic level. In six adult human lungs, the mean alveolar number was 480 million (range: 274–790 million; coefficient of variation: 37%). Alveolar number was closely related to total lung volume, with larger lungs having considerably more alveoli. The mean size of a single alveolus was rather constant with 4.2 × 106μm3 (range: 3.3–4.8 × 106μm3; coefficient of variation: 10%), irrespective of the lung size. One cubic m...

Lessons from the Genome Sequence of Neurospora crassa: Tracing the Path from Genomic Blueprint to Multicellular Organism

Abstract: We present an analysis of over 1,100 of the approximately 10,000 predicted proteins encoded by the genome sequence of the filamentous fungus Neurospora crassa. Seven major areas of Neurospora genomics and biology are covered. First, the basic features of the genome, including the automated assembly, gene calls, and global gene analyses are summarized. The second section covers components of the centromere and kinetochore complexes, chromatin assembly and modification, and transcription and translation initiation factors. The third area discusses genome defense mechanisms, including repeat induced point mutation, quelling and meiotic silencing, and DNA repair and recombination. In the fourth section, topics relevant to metabolism and transport include extracellular digestion; membrane transporters; aspects of carbon, sulfur, nitrogen, and lipid metabolism; the mitochondrion and energy metabolism; the proteasome; and protein glycosylation, secretion, and endocytosis. Environmental sensing is the focus of the fifth section with a treatment of two-component systems; GTP-binding proteins; mitogen-activated protein, p21-activated, and germinal center kinases; calcium signaling; protein phosphatases; photobiology; circadian rhythms; and heat shock and stress responses. The sixth area of analysis is growth and development; it encompasses cell wall synthesis, proteins important for hyphal polarity, cytoskeletal components, the cyclin/cyclin-dependent kinase machinery, macroconidiation, meiosis, and the sexual cycle. The seventh section covers topics relevant to animal and plant pathogenesis and human disease. The results demonstrate that a large proportion of Neurospora genes do not have homologues in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe. The group of unshared genes includes potential new targets for antifungals as well as loci implicated in human and plant physiology and disease.

A novel syndrome combining thyroid and neurological abnormalities is associated with mutations in a monocarboxylate transporter gene.

Abstract: Thyroid hormones are iodothyronines that control growth and development, as well as brain function and metabolism Although thyroid hormone deficiency can be caused by defects of hormone synthesis and action, it has not been linked to a defect in cellular hormone transport In fact, the physiological role of the several classes of membrane transporters remains unknown We now report, for the first time, mutations in the monocarboxylate transporter 8 (MCT8) gene, located on the X chromosome, that encodes a 613–amino acid protein with 12 predicted transmembrane domains The propositi of two unrelated families are males with abnormal relative concentrations of three circulating iodothyronines, as well as neurological abnormalities, including global developmental delay, central hypotonia, spastic quadriplegia, dystonic movements, rotary nystagmus, and impaired gaze and hearing Heterozygous females had a milder thyroid phenotype and no neurological defects These findings establish the physiological importance of MCT8 as a thyroid hormone transporter

Plant-insect interactions in fragmented landscapes.

Abstract: Population and community ecology need a large-scale perspective because local patterns (of biodiversity) and processes (trophic interactions) are influenced by the regional setting. The ratio of the foraging range and/or dispersal ability to the distance between landscape elements influences local population dynamics. The spatial scale experienced by a species may be linked to its trophic level and also to traits such as body size, resource specialization, rarity, and population size variability. Hence, communities are assemblages of species with different spatial strategies. Effects of habitat loss and habitat fragmentation on plant-herbivore, herbivore-enemy, as well as plant-pollinator interactions are contingent on species and landscape. Metapopulation theory provides a unifying frame to approach plant-insect systems across fragmented landscape, although the landscape context is often ignored. In some cases theory is far ahead of empirical research. We call for more population data on large spatial and temporal scales to better understand plant-insect populations across fragmented landscapes.

Phylogeny and evolution of ferns (monilophytes) with a focus on the early leptosporangiate divergences

Abstract: The phylogenetic structure of ferns (5 monilophytes) is explored here, with a special focus on the early divergences among leptosporangiate lineages. Despite considerable progress in our understanding of fern relationships, a rigorous and comprehensive analysis of the early leptosporangiate divergences was lacking. Therefore, a data set was designed here to include critical taxa that were not included in earlier studies. More than 5000 bp from the plastid (rbcL, atpB, rps4) and the nuclear (18S rDNA) genomes were sequenced for 62 taxa. Phylogenetic analyses of these data (1) confirm that Osmundaceae are sister to the rest of the leptosporangiates, (2) resolve a diverse set of ferns formerly thought to be a subsequent grade as possibly monophyletic (((Dipteridaceae, Matoniaceae), Gleicheniaceae), Hymenophyllaceae), and (3) place schizaeoid ferns as sister to a large clade of ‘‘core leptosporangiates’’ that includes heterosporous ferns, tree ferns, and polypods. Divergence time estimates for ferns are reported from penalized likelihood analyses of our molecular data, with constraints from a reassessment of the fossil record.

BCI competition 2003-data set IIb: support vector machines for the P300 speller paradigm

Abstract: We propose an approach to analyze data from the P300 speller paradigm using the machine-learning technique support vector machines. In a conservative classification scheme, we found the correct solution after five repetitions. While the classification within the competition is designed for offline analysis, our approach is also well-suited for a real-world online solution: It is fast, requires only 10 electrode positions and demands only a small amount of preprocessing.

The efficacy of short-term psychodynamic psychotherapy in specific psychiatric disorders: a meta-analysis.

Abstract: Background The efficacy of psychodynamic therapy is controversial Previous meta-analyses have reported discrepant results Objective To test the efficacy of short-term psychodynamic psychotherapy (STPP) in specific psychiatric disorders by performing a meta-analysis of more recent studies We assessed outcomes in target problems, general psychiatric symptoms, and social functioning Design We identified studies of STPP published between January 1, 1970, and September 30, 2004, by means of a computerized search using MEDLINE, PsycINFO, and Current Contents Rigorous inclusion criteria, included randomized controlled trials, use of treatment manuals and ensurance of treatment integrity, therapists experienced or specifically trained in STPP, treatment of patients with specific psychiatric disorders, reliable and valid diagnostic measures, and data necessary to calculate effect sizes Studies of interpersonal therapy were excluded Seventeen studies fulfilled the inclusion criteria The information was extracted by 3 raters Effect sizes were calculated for target problems, general psychiatric symptoms, and social functioning using the data published in the original studies To examine the stability of outcome, we assessed effect sizes separately for end of therapy and follow-up assessment The effect sizes of STPP were compared with those of waiting-list control patients, treatments as usual, and other forms of psychotherapy Results Short-term psychodynamic psychotherapy yielded significant and large pretreatment-posttreatment effect sizes for target problems (139), general psychiatric symptoms (090), and social functioning (080) These effect sizes were stable and tended to increase at follow-up (157, 095, and 119, respectively) The effect sizes of STPP significantly exceeded those of waiting-list controls and treatments as usual No differences were found between STPP and other forms of psychotherapy Conclusions Short-term psychodynamic psychotherapy proved to be an effective treatment in psychiatric disorders However, further research of STPP in specific psychiatric disorders is needed, including a study of the active ingredients of STPP Effectiveness studies should be included

Temperature dependence of Zr in rutile: empirical calibration of a rutile thermometer

Abstract: Rutile is an important carrier of high field strength elements (HFSE; Zr, Nb, Mo, Sn, Sb, Hf, Ta, W). Its Zr content is buffered in systems with quartz and zircon as coexisting phases. The effects of temperature (T) and pressure (P) on the Zr content in rutile have been empirically calibrated in this study by analysing rutile–quartz–zircon assemblages of 31 metamorphic rocks spanning a T range from 430 to 1,100°C. Electron microprobe measurements show that Zr concentrations in rutile vary from 30 to 8,400 ppm across this temperature interval, correlating closely with metamorphic grade. The following thermometer has been formulated based on the maximum Zr contents of rutile included in garnet and pyroxene: % MathType!Translator!2!1!AMS LaTeX.tdl!TeX -- AMS-LaTeX! % MathType!MTEF!2!1!+- % feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamivaiaabI % cacaqGPbGaaeOBaiaaysW7daahaaWcbeqaaiablIHiVbaakiaaboea % caqGPaGaaeiiaiaab2dacaqGGaGaaeymaiaabkdacaqG3aGaaeOlai % aabIdacaaMc8Uaey41aqRaaeiBaiaab6gacaqGGaGaaeikaiaabQfa % caqGYbGaaGPaVlaabMgacaqGUbGaaGPaVlaabchacaqGWbGaaeyBai % aabMcacaaMc8UaeyOeI0Iaaeymaiaabcdaaaa!5848! $$ T{\text{(in}}\;^ \circ {\text{C) = 127}}{\text{.8}}\, \times {\text{ln (Zr}}\,{\text{in}}\,{\text{ppm)}}\, - {\text{10}} $$ No pressure dependence was observed. An uncertainty in absolute T of ±50°C is inherited from T estimates of the natural samples used. A close approach to equilibrium of Zr distribution between zircon and rutile is suggested based on the high degree of reproducability of Zr contents in rutiles from different rock types from the same locality. At a given locality, the calculated range in T is mostly ±10°C, indicating the geological and analytical precision of the rutile thermometer. Possible applications of this new geothermometer are discussed covering the fields of ultrahigh temperature (UHT) granulites, sedimentary provenance studies and metamorphic field gradients.

Biodiversity indicator groups of tropical land‐use systems: comparing plants, birds, and insects

Abstract: Tropical landscapes are dominated by land-use systems, but their contribution to the conservation of biodiversity is largely unknown. Since changes in biodiversity in response to human impact are known to differ widely among taxonomic groups and guilds, there is a need for multidisciplinary collaboration of plant, vertebrate, and invertebrate experts. We used inventories of trees, understory plants, birds (subdivided into endemics, insectivores, frugivores/nectar feeders), butterflies (endemics, fruit feeders), and dung bee- tles in Sulawesi (Indonesia) to characterize a gradient from near-primary to secondary forests, agroforestry systems, and annual crops. As expected, overall species richness tended to decrease within this gradient of increasing habitat modification, but, in contrast to pre- vious studies, we found the species richness between most taxonomic groups to be signif- icantly correlated (36 out of 38 pairwise comparisons). However, on average only 48% of the variance could be explained (within the five main groups), and only a few taxonomic groups/guilds turned out to be good predictors for others: for example, trees for fruit- and nectar-feeding birds (88% explanation) and fruit-feeding butterflies (83%), endemic birds for endemic butterflies (72%), and frugivorous/nectar-feeding birds for fruit-feeding but- terflies (67%). Although biodiversity of land-use systems showed taxonomic group- and guild-specific differences, most groups were affected in a similar way by habitat modifi- cation. Near-primary forest sites proved to be of principal importance for conservation; however, land-use systems such as secondary forests (for understory plants, birds, and butterflies) and agroforestry systems (for butterflies) supported relatively high numbers of species and might play a significant role for biodiversity conservation in tropical landscapes.

Genomic Analysis of the Nitrate Response Using a Nitrate Reductase-Null Mutant of Arabidopsis

Abstract: A nitrate reductase (NR)-null mutant of Arabidopsis was constructed that had a deletion of the major NR gene NIA2 and an insertion in the NIA1 NR gene. This mutant had no detectable NR activity and could not use nitrate as the sole nitrogen source. Starch mobilization was not induced by nitrate in this mutant but was induced by ammonium, indicating that nitrate was not the signal for this process. Microarray analysis of gene expression revealed that 595 genes responded to nitrate (5 mm nitrate for 2 h) in both wild-type and mutant plants. This group of genes was overrepresented most significantly in the functional categories of energy, metabolism, and glycolysis and gluconeogenesis. Because the nitrate response of these genes was NR independent, nitrate and not a downstream metabolite served as the signal. The microarray analysis also revealed that shoots can be as responsive to nitrate as roots, yet there was substantial organ specificity to the nitrate response.

Co-existing disorders in ADHD -- implications for diagnosis and intervention.

Abstract: Background It is only recently that comorbidity in ADHD has come to the forefront as one of the most important aspects of the disorder. It is agreed that, often, these problems are at least as important as ADHD in contributing to the longer term outcome in the individual child. Objective To provide the reader with basic information about clinics and treatment of comorbidity in ADHD. Method Review of the empirically based literature. Results ADHD exists in a surprisingly high frequency together with a broad range of child neuropsychiatric disorders. This is accompanied with many still unresolved treatment problems. Conclusion It would not be appropriate to develop ADHD–services where clinicians would only have expertise in ADHD as such. Anyone working with children, adolescents and adults with ADHD would need to have training in general neuropsychiatry. Further research in this field is urgently needed. (Less)

The Complete Genome Sequence of Propionibacterium Acnes, a Commensal of Human Skin

Abstract: Propionibacterium acnes is a major inhabitant of adult human skin, where it resides within sebaceous follicles, usually as a harmless commensal although it has been implicated in acne vulgaris formation. The entire genome sequence of this Gram-positive bacterium encodes 2333 putative genes and revealed numerous gene products involved in degrading host molecules, including sialidases, neuraminidases, endoglycoceramidases, lipases, and pore-forming factors. Surface-associated and other immunogenic factors have been identified, which might be involved in triggering acne inflammation and other P. acnes-associated diseases.

Non‐native invasive earthworms as agents of change in northern temperate forests

Abstract: Exotic earthworms from Europe and Asia are invading many northern forests in North America that currently lack native earthworms, providing an opportunity to assess the role of this important group of invertebrates in forest ecosystems Research on earthworm invasions has focused on changes in soil structure and carbon (C) and nitrogen (N) cycling that occur following invasion These changes include the mixing of organic and mineral soil horizons, decreases in soil C storage, and equivocal effects on N cycling Less well studied are changes in the soil foodwebs that accompany earthworm invasion Soils of north temperate forests harbor a tremendous diversity of microorganisms and invertebrates, whose distribution and abundance can be substantially altered by earthworm invasion Furthermore, invasive earthworms can affect understory plant communities, raising concerns over the loss of rare native herbs in some areas The ecological consequences of earthworm invasion are mediated through physical, geochemica

Domino reactions in the synthesis of heterocyclic natural products and analogs

Abstract: Domino reactions are defined as processes of two or more bond-forming reactions under identical conditions, in which the subsequent transformation takes place at the func- tionalities obtained in the former transformation. They allow the efficient synthesis of com- plex molecules from simple substrates in an ecologically and economically favorable way. A very powerful domino process is the domino Knoevenagel-hetero-Diels-Alder re- action, in which an aldehyde or an β-ketoester is condensed with a 1,3-dicarbonyl compound or a heteroanalog to give a 1-oxa-1,3-butadiene, which can undergo an inter- or intramolec- ular hetero-Diels-Alder reaction with dienophiles such as enol ethers or alkenes. The products are dihydropyrans, which can be transformed in a variety of ways. Thus, an extension of the process is the synthesis of highly substituted pyrrolidines, piperidines, and azepanes using aminoaldehydes. The process has also been employed for the enantio- selective total synthesis of a variety of alkaloids, such as indol- and ipecacuanha alkaloids. In another domino process, erythrina and homoerythrina alkaloids have been prepared from simple phenylethylamines and ketoesters.

Hippocampal Synapses Depend on Hippocampal Estrogen Synthesis

Abstract: Estrogens have been described to induce synaptogenesis in principal neurons of the hippocampus and have been shown to be synthesized and released by exactly these neurons. Here, we have focused on the significance of local estrogen synthesis on spine synapse formation and the synthesis of synaptic proteins. To this end, we reduced hippocampal estrogen synthesis in vitro with letrozole, a reversible nonsteroidal aromatase inhibitor. In hippocampal slice cultures, letrozole treatment resulted in a dose-dependent decrease of 17β-estradiol as quantified by RIA. This was accompanied by a significant decrease in the density of spine synapses and in the number of presynaptic boutons. Quantitative immunohistochemistry revealed a downregulation of spinophilin, a marker of dendritic spines, and synaptophysin, a protein of presynaptic vesicles, in response to letrozole. Surprisingly, no increase in the density of spines, boutons, and synapses and in spinophilin expression was seen after application of estradiol to the medium of cultures that had not been treated with letrozole. However, synaptophysin expression was upregulated under these conditions. Our results point to an essential role of endogenous hippocampal estrogen synthesis in the maintenance of hippocampal spine synapses.