Follow-up of a family group suffering from ichthyosis hystrix type Curth-Macklin

Summary A family examined by Curth and Macklin in 1952 and found to suffer from generalized or localized forms of ichthyosis, was reexamined in 1970. The concept that the disorder had been conditioned by a dominant gene which manifested itself with varying degrees of severity in the various family members, seemed proved again.Analysis for autosomal linkage was done with an IBM model 1130 computer. Linkage to the AB0 locus, as close as 10 recombination units was ruled out. Very close linkage was also excluded for P, Rh, Duffy, Kidd, Gm, haptoglobin, Ag, and phosphoglucomutase. Loose linkage was not ruled out with respect to any marker.Due to clinical, histopathological and ultrastructural findings, our cases are regarded as an independent nosological entity and are therefore to be separated from the other forms of hystrix-like ichthyosis.

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Zusammenfassung Die von Curth u. Macklin 1952 erstmals untersuchte Familie mit generalisierten oder lokalisierten Formen von Ichthyosis wurde 1970 erneut untersucht. Die Annahme eines autosomal dominanten Erbganges mit wechselnder Expressivität konnte erneut bestätigt werden.Mit einem IBM Computer Modell 1130 wurden marker-Analysen und Kopplungsstudien durchgeführt. Kopplung an den AB0-Locus in einer Entfernung von 10 Rekombinations-Einheiten konnte ausgeschlossen werden. Enge Kopplung wurde außerdem für die marker P, Rh, Duffy, Kidd, Gm, Haptoglobin, Ag und Phosphoglucomutase ausgeschlossen. Nicht für jeden der geprüften marker konnte Kopplung generell ausgeschlossen werden.Die beschriebenen Fälle werden auf Grund der klinischen, histopathologischen und elektronenoptischen Befunde als eigenständige nosologische Entität angesehen und von den übrigen hystrixartigen Ichthyosen abgetrennt.

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Supported by the Deutsche Forschungsgemeinschaft, Sonderforschungsbereich Klinische Genetik, SFB 35, programs 5 and 7.     

Cell lines from xeroderma pigmentosum complementation group A lack a single-stranded-DNA-binding activity

Human fibroblasts and HeLa cells contain two major DNA-binding activities for superhelical DNA, which can be separated by phosphocellulose chromatography. The DNA-binding activity which elutes first from the column coelutes with and is probably identical to a single-stranded-DNA-binding activity. The second activity has been characterized previously. It binds preferentially to super-helical DNA containing DNA damage, but does not bind to single-stranded DNA. Five cell lines derived from patients with the repairdeficiency syndrome xeroderma pigmentosum (XP) were analyzed for the presence of these binding activities. Four of the cell lines were from the A-complementation group and one was from the D-complementation group of XP. The binding activity with preference for damaged DNA was present in all cell lines. The single-stranded-DNA-binding activity was present in the XP-D cell line but was absent or reduced in all of the four XP-A cell lines tested.     

Maternal immune activation induces GAD1 and GAD2 promoter remodeling in the offspring prefrontal cortex

Maternal infection during pregnancy increases the risk of neurodevelopmental disorders in the offspring. In addition to its influence on other neuronal systems, this early-life environmental adversity has been shown to negatively affect cortical γ-aminobutyric acid (GABA) functions in adult life, including impaired prefrontal expression of enzymes required for GABA synthesis. The underlying molecular processes, however, remain largely unknown. In the present study, we explored whether epigenetic modifications represent a mechanism whereby maternal infection during pregnancy can induce such GABAergic impairments in the offspring. We used an established mouse model of prenatal immune challenge that is based on maternal treatment with the viral mimetic poly(I:C). We found that prenatal immune activation increased prefrontal levels of 5-methylated cytosines (5mC) and 5-hydroxymethylated cytosines (5hmC) in the promoter region of GAD1, which encodes the 67-kDa isoform of the GABA-synthesising enzyme glutamic acid decarboxylase (GAD67). The early-life challenge also increased 5mC levels at the promoter region of GAD2, which encodes the 65-kDa GAD isoform (GAD65). These effects were accompanied by elevated GAD1 and GAD2 promoter binding of methyl CpG-binding protein 2 (MeCP2) and by reduced GAD67 and GAD65 mRNA expression. Moreover, the epigenetic modifications at the GAD1 promoter correlated with prenatal infection-induced impairments in working memory and social interaction. Our study thus highlights that hypermethylation of GAD1 and GAD2 promoters may be an important molecular mechanism linking prenatal infection to presynaptic GABAergic impairments and associated behavioral and cognitive abnormalities in the offspring.     

Fully Metal-Coated Scanning Near-Field Optical Microscopy Probes with Spiral Corrugations for Superfocusing under Arbitrarily Oriented Linearly Polarised Excitation

We study the effect of a spiral corrugation on the outer surface of a fully metal-coated scanning near-field optical microscopy (SNOM) probe using the finite element method. The introduction of a novel form of asymmetry, devoid of any preferential spatial direction and covering the whole angular range of the originally axisymmetric tip, allows attaining strong field localization for a linearly polarised mode with arbitrary orientation. Compared to previously proposed asymmetric structures which require linearly polarised excitation properly oriented with respect to the asymmetry, such a configuration enables significant simplification in mode injection. In fact, not only is the need for the delicate procedure to generate radially polarised beams overcome, but also the relative alignment between the linearly polarised beam and the tip modification is no longer critical.     

Fire as a tool in the management of a savanna/dry forest reserve in Madagascar

Abstract. The possible use of fire for the management of the Ankarafantsika Reserve in the northwest of Madagascar and of its surrounding area is studied. Within this savanna landscape large parts of the remaining dry forests still exist with a unique biotic diversity, both in terms of total number of species and endemism. Unfortunately, mainly man-induced uncontrolled fires threaten these forests. Actual and former fire regimes of the local communities are analysed. The use of fire is an integrated part of land use and is also governed by socio-cultural traditions. The impact of fire on the dynamics of dry forests and grass savannas is studied considering the specifics of different fire regimes. We propose that a deliberate and controlled use of fire respecting the vegetation stage and the defined objectives could be an appropriate management tool. The strategy of a fire management is elaborated considering both the conservation of biodiversity and improvement of the livelihood of the local population depending upon the Reserve's resources. Obviously, a sustainable management of the natural resources requires a substantial participation of the community.     

Bacterial Signal Transduction by Cyclic Di-GMP and Other Nucleotide Second Messengers

The first International Symposium on c-Di-GMP Signaling in Bacteria (22 to 25 March 2015, Harnack-Haus, Berlin, Germany) brought together 131 molecular microbiologists from 17 countries to discuss recent progress in our knowledge of bacterial nucleotide second messenger signaling. While the focus was on signal input, synthesis, degradation, and the striking diversity of the modes of action of the current second messenger paradigm, i.e., cyclic di-GMP (c-di-GMP), “classics” like cAMP and (p)ppGpp were also presented, in novel facets, and more recent “newcomers,” such as c-di-AMP and c-AMP-GMP, made an impressive appearance. A number of clear trends emerged during the 30 talks, on the 71 posters, and in the lively discussions, including (i) c-di-GMP control of the activities of various ATPases and phosphorylation cascades, (ii) extensive cross talk between c-di-GMP and other nucleotide second messenger signaling pathways, and (iii) a stunning number of novel effectors for nucleotide second messengers that surprisingly include some long-known master regulators of developmental pathways. Overall, the conference made it amply clear that second messenger signaling is currently one of the most dynamic fields within molecular microbiology, with major impacts in research fields ranging from human health to microbial ecology.     

Assay to mechanically tune and optically probe fibrillar fibronectin conformations from fully relaxed to breakage

In response to growing needs for quantitative biochemical and cellular assays that address whether the extracellular matrix (ECM) acts as a mechanochemical signal converter to co-regulate cellular mechanotransduction processes, a new assay is presented where plasma fibronectin fibers are manually deposited onto elastic sheets, while force-induced changes in protein conformation are monitored by fluorescence resonance energy transfer (FRET). Fully relaxed assay fibers can be stretched at least 5-6 fold, which involves Fn domain unfolding, before the fibers break. In native fibroblast ECM, this full range of stretch-regulated conformations coexists in every field of view confirming that the assay fibers are physiologically relevant model systems. Since alterations of protein function will directly correlate with their extension in response to force, the FRET vs. strain curves presented herein enable the mapping of fibronectin strain distributions in 2D and 3D cell cultures with high spatial resolution. Finally, cryptic sites for fibronectin's N-terminal 70-kD fragment were found to be exposed at relatively low strain, demonstrating the assay's potential to analyze stretch-regulated protein-protein interactions.     

In vitro spore formation and completion of the asexual life cycle of Neozygites parvispora, an obligate biotrophic pathogen of thrips

Capilliconidia, the asexual secondary spores of Neozygites parvispora (Zygomycetes, Entomophthorales) were produced in vitro either by entrapment of vegetative cells (hyphal bodies) in alginate pellets or after plating them onto water agar. Cultivation of the fungus for 3 days in a medium lacking hemolymph increased spore production 30 to 40-fold, and about 10% of the cells produced capilliconidia. The in vitro produced capilliconidia were infectious to Thrips tabaci and the fungus was reisolated from infected insects, thus completing its asexual life cycle under laboratory conditions. A decrease in capilliconidia production and a modification of the number of nuclei per spore were observed for isolates cultivated in vitro for more than 2 months, but subsequent host passages restored and increased sporulation efficiency without influencing the number of nuclei. Fungal cultures were stored at —80 °C for up to 7 months, and the capability to sporulate and infect T. tabaci was preserved. A bioassay procedure for infecting T. tabaci with N. parvispora is described, the first mycosed insects dying usually after 8 d of incubation.