Rhythmic mycelial growth in Podospora anserina

Summary Treatment of mycelial fragments with EMS and NMU yielded 15 revertants of the pleiotropic mutant zonata of Podospora anserina. Analysis by biological, biochemical and genetical methods has revealed that the reversions are caused by back mutation within the zonata locus. This leads to the conclusion that a point mutation causes the morphological and biochemical alterations in this mutant.A working hypothesis for the primary action of this gene and its significance for the elucidation of morphogenesis and of pleiotropism are discussed.With support of the Deutsche Forschungsgemeinschaft, Bad Godesberg (Germany).     

Co-infection by Cryptococcus neoformans and Mycobacterium aKeikawusvium intracellulare in AIDS

In the observation of various opportunistic pathogens in HIV-positive persons, co-infection by Cryptococcus neoformans together with Mycobacterium avium intracellulare was found if there was a CD4 lymphocyte count as low as 3–20μl. In 1540 HIV-positive patients under treatment at a Berlin hospital (Auguste–Viktoria–Krankenhaus) during 1985–1994, all AIDS-relevant diseases were examined in a multivariate analysis as variables of influence on the manifestation of a systemic Mycobacterium avium complex (MAC) infection. The analysis involved data on 36 cases of cryptococcosis and 202 cases with a typical clinical course in whom MAC had been detected at sterile body sites. As significant and independent factors of influence, the following were identified: C. neoformans infection, wasting syndrome, lower age, low CD4 lymphocyte count and preceding Pneumocystis carinii pneumonia (PcP) prophylaxis. Cryptococcosis ranged first with an odds ratio of 2.75. The concomitant manifestation of cryptococcosis and systemic MAC infection in six patients is shown. Because both opportunists, C. neoformans and avian mycobacteria, may have their common habitat in droppings of defined species of pet birds, a common source of infection deserves further clinical and epidemiological attention. This revised version was published online in August 2006 with corrections to the Cover Date.     

Group Sequential Monitoring with Arbitrary Inspection Times

The classical group sequential test procedures that were proposed by Pocock (1977) and O'Brien and Fleming (1979) rest on the assumption of equal sample sizes between the interim analyses. Regarding this it is well known that for most situations there is not a great amount of additional Type I error if monitoring is performed for unequal sample sizes between the stages. In some cases, however, problems can arise resulting in an unacceptable liberal behavior of the test procedure. In this article worst case scenarios in sample size imbalancements between the inspection times are considered. Exact critical values for the Pocock and the O'Brien and Fleming group sequential designs are derived for arbitrary and for varying but bounded sample sizes. The approach represents a reasonable alternative to the flexible method that is based on the Type I error rate spending function. The SAS syntax for performing the calculations is provided. Using these procedures, the inspection times or the sample sizes in the consecutive stages need to be chosen independently of the data observed so far.     

Heterogeneity of microvascular endothelial cells isolated from human term placenta and macrovascular umbilical vein endothelial cells

The present study compares some phenotypic and physiologic characteristics of microvascular and macrovascular endothelial cells from within one human organ. To this end microvascular endothelial cells from human full-term placenta (PLEC) were isolated using a new method and compared with macrovascular human umbilical vein endothelial cells (HUVEC) and an SV40-transformed placental venous endothelial cell line (HPEC-A2). PLEC were isolated by enzymatic perfusion of small placental vessels, purified on a density gradient and cultured subsequently. Histological sections of the enzyme-treated vessels showed a selective removal of the endothelial lining in the perfused placental cotyledons. The endothelial identity of the cells was confirmed by staining with the endothelial markers anti-von Willebrand factor, Ulex europaeus lectin and anti-QBEND10. The cells internalized acetylated low-density lipoprotein and did not show immunoreactivity with markers for macrophages, smooth muscle cells and fibroblasts. The spindle-shaped PLEC grew in swirling patterns similar to that described for venous placental endothelial cells. However, scanning electron microscopic examination clearly showed that PLEC remained elongated at the confluent state, in contrast to the more polygonal phenotype of HPEC-A2 and HUVEC that were studied in parallel. The amount of vasoactive substances (endothelin-1,2, thromboxane, angiotensin II, prostacyclin) released into the culture medium and the proliferative response to cytokines was more similar to human dermal microvessels (MIEC) derived from non-fetal tissue than to HUVEC. Potent mitogens such as vascular endothelial growth factors (VEGF121, VEGF165) and basic fibroblast growth factor (FGF-2) induced proliferation of all endothelial cell types. Placental growth factors PIGF-1 and PIGF-2 effectively stimulated cell proliferation on PLEC (142 +/- 7% and 173 +/- 10%) and MIEC (160 +/- 20% and 143 +/- 28%) in contrast to HUVEC (9 +/- 8% and 15 +/- 20%) and HPEC-A2 (15 +/- 7% and 24 +/- 6%) after 48 h incubation time under serum-free conditions. These data support evidence for (1) the microvascular identity of the isolated PLEC described in this study, and (2) the phenotypic and physiologic heterogeneity of micro- and macrovascular endothelial cells within one human organ.     

The Gustatory Neural Response Function

With few exceptions, afferent neurons in the various sensory systems respond to wide ranges of stimuli. In those sensory systems for which the stimulus dimensions are understood, the response functions of these neurons may be described; they are usually simple functions with one maximum, although many variations exist. In the chemical senses, the stimulus dimensions are not known, and thus the neural response functions of these neurons have never been described. The present paper presents methods to determine these response functions and the stimulus dimensions for the chemical senses. A tentative response function for taste is developed, and preliminary steps are taken toward disclosing the stimulus dimensions.     

JunctionViewer: customizable annotation software for repeat-rich genomic regions

Background  

Repeat-rich regions such as centromeres receive less attention than their gene-rich euchromatic counterparts because the former are difficult to assemble and analyze. Our objectives were to 1) map all ten centromeres onto the maize genetic map and 2) characterize the sequence features of maize centromeres, each of which spans several megabases of highly repetitive DNA. Repetitive sequences can be mapped using special molecular markers that are based on PCR with primers designed from two unique "repeat junctions". Efficient screening of large amounts of maize genome sequence data for repeat junctions, as well as key centromere sequence features required the development of specific annotation software.     

Differences in brain function and changes with intervention in children with poor spelling and reading abilities

Previous fMRI studies in English-speaking samples suggested that specific interventions may alter brain function in language-relevant networks in children with reading and spelling difficulties, but this research strongly focused on reading impaired individuals. Only few studies so far investigated characteristics of brain activation associated with poor spelling ability and whether a specific spelling intervention may also be associated with distinct changes in brain activity patterns. We here investigated such effects of a morpheme-based spelling intervention on brain function in 20 children with comparatively poor spelling and reading abilities using repeated fMRI. Relative to 10 matched controls, children with comparatively poor spelling and reading abilities showed increased activation in frontal medial and right hemispheric regions and decreased activation in left occipito-temporal regions prior to the intervention, during processing of a lexical decision task. After five weeks of intervention, spelling and reading comprehension significantly improved in the training group, along with increased activation in the left temporal, parahippocampal and hippocampal regions. Conversely, the waiting group showed increases in right posterior regions. Our findings could indicate an increased left temporal activation associated with the recollection of the new learnt morpheme-based strategy related to successful training.     

Vertical transmission and overwintering of microsporidia in the gypsy moth, Lymantria dispar

Vertical transmission and the overwintering success of three different microsporidia infecting Lymantria dispar (Lepidoptera: Lymantriidae) larvae were investigated. Endoreticulatus schubergi, a midgut pathogen, was transmitted to offspring via female and male via the egg chorion (transovum transmission). Between 8% and 29% of the emerging larvae became infected. No spores of E. schubergi were found in surface-washed eggs. Nosema lymantriae, a microsporidium that causes systemic infections, was transovarially transmitted. Between 35% and 72% of the progeny were infected. Vairimorpha disparis, a fat body pathogen, was not vertically transmitted. The infectivity of spores that overwintered in cadavers of infected L. dispar varied by species, placement in the environment, and weather conditions. Spores of E. schubergi were still infective after an eight month exposure period of cadavers on the ground. Spores of N. lymantriae and V. disparis remained highly infective only when cadavers overwintered under a more or less continuous snow cover for four months.     

Life cycle assessment of the selective catalytic reduction process for power plants

The overall reduction of the environmental impact by the use of selective catalytic reduction (SCR) of nitrogen oxide emissions in power plants was determined by strict application of ISO 14040 and ISO/DIS 14041. Special emphasis was placed on the implementation of the total product life cycle (PLC) of ammonium molybdate as a key input material. The environmental impact was generated by application of the life cycle assessment (LCA) concept of “ecoscarcity” and integrated in the life cycle inventory analysis (LCI) of SCR systems. The LCI was used to generate the life cycle impact assessment (LC1A) by use of different quantitative valuation methods. Under consideration of the overall LCIA results and the environmental protection costs of the SCR variants, the Ecological Effectiveness of the SCR alternatives was determined. The results enable plausible conclusions with regard to the ecological advantages of the use of deNOx catalysts in the SCR used in hard-coal fired power plants.     

Contrasting Patterns of Genetic Differentiation among Blackcaps (Sylvia atricapilla) with Divergent Migratory Orientations in Europe

Migratory divides are thought to facilitate behavioral, ecological, and genetic divergence among populations with different migratory routes. However, it is currently contentious how much genetic divergence is needed to maintain distinct migratory behavior across migratory divides. Here we investigate patterns of neutral genetic differentiation among Blackcap (Sylvia atricapilla) populations with different migratory strategies across Europe. We compare the level of genetic divergence of populations migrating to southwestern (SW) or southeastern (SE) wintering areas with birds wintering in the British Isles following a recently established northwesterly (NW) migration route. The migratory divide between SW and SE wintering areas can be interpreted as a result of a re-colonization process after the last glaciation. Thus we predicted greater levels of genetic differentiation among the SW/SE populations. However, a lack of genetic differentiation was found between SW and SE populations, suggesting that interbreeding likely occurs among Blackcaps with different migratory orientations across a large area; therefore the SW/SE migratory divide can be seen as diffuse, broad band and is, at best, a weak isolating barrier. Conversely, weak, albeit significant genetic differentiation was evident between NW and SW migrants breeding sympatrically in southern Germany, suggesting a stronger isolating mechanism may be acting in this population. Populations located within/near the SW/SE contact zone were the least genetically divergent from NW migrants, confirming NW migrants likely originated from within the contact zone. Significant isolation-by-distance was found among eastern Blackcap populations (i.e. SE migrants), but not among western populations (i.e. NW and SW migrants), revealing different patterns of genetic divergence among Blackcap populations in Europe. We discuss possible explanations for the genetic structure of European Blackcaps and how gene flow influences the persistence of divergent migratory behaviors.