Emulating the early phases of human tooth development in vitro

Functional in vitro models emulating the physiological processes of human organ formation are invaluable for future research and the development of regenerative therapies. Here, a developmentally inspired approach is pursued to reproduce fundamental steps of human tooth organogenesis in vitro using human dental pulp cells. Similar to the in vivo situation of tooth initiating mesenchymal condensation, a 3D self-organizing culture was pursued resulting in an organoid of the size of a human tooth germ with odontogenic marker expression. Furthermore, the model is capable of epithelial invagination into the condensed mesenchyme, mimicking the reciprocal tissue interactions of human tooth development. Comprehensive transcriptome analysis revealed activation of well-studied as well as rather less investigated signaling pathways implicated in human tooth organogenesis, such as the Notch signaling. Early condensation in vitro revealed a shift to the TGFß signal transduction pathway and a decreased RhoA small GTPase activity, connected to the remodeling of the cytoskeleton and actin-mediated mechanotransduction. Therefore, this in vitro model of tooth development provides a valuable model to study basic human developmental mechanisms.DFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli

Genotipagem de Toxoplasma gondii em galinhas domésticas em uma área rural do Rio Grande do Sul, Brasil

Free-range chickens may ingest oocysts of T. gondii present in the environment and consequently harbor virulent strains of this parasite in different tissues, without any clinical signs. Isolation of T. gondii through bioassays on mice and cats from naturally infected chicken tissues has been described in several countries, demonstrating the importance of free-range chickens in the transmission of this parasite. The aim of this study was the genotypic characterization of T. gondii isolates obtained from naturally infected free-range chickens in a rural area of the state of Rio Grande do Sul, Brazil. Brain and heart tissue from 12 chickens seropositive for T. gondii were processed using peptic digestion technique for parasite isolation. From 12 samples subjected to mouse bioassay, nine isolates were obtained. RFLP-PCR genotypic characterization was performed using 11 genetic markers: SAG1, 5'-3'SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29- 2, L358, PK1 and Apico. Genetic characterization of the isolates revealed the presence of five atypical genotypes according to ToxoDB (# 11, # 55, # 64, # 140 and # 163). Our results showed a wide genetic diversity of T. gondii in free-range chickens in this region.Galinhas criadas ao ar livre podem ingerir oocistos de T. gondii presentes no ambiente e, com isso, albergar cepas virulentas desse parasita em diferentes tecidos, sem sinais clínicos. O isolamento de T. gondii por meio de bioensaios em camundongos e gatos, a partir de tecidos de galinhas naturalmente infectadas, tem sido descrito em vários países. Isso demonstra a importância das galinhas caipiras na epidemiologia desse parasita. O objetivo deste trabalho foi caracterizar genotipicamente isolados de T. gondii obtidos de galinhas caipiras naturalmente infectadas em uma área rural do município de Santa Maria, estado do Rio Grande do Sul, Brasil. Fragmentos de cérebro e de coração, de 12 galinhas soropositivas para T. gondii, foram processados pela técnica de digestão péptica para isolamento do parasita. Das 12 amostras submetidas a bioensaio com camundongos, nove isolados foram obtidos. A caracterização genotípica por RFLP-PCR foi realizada utilizando-se 11 marcadores genéticos: SAG1, 5'- 3'SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 e Apico e revelou a presença de cinco genótipos atípicos de acordo com o ToxoDB (# 11, # 55, # 64, # 140 e # 163). Os resultados mostraram uma ampla diversidade genética de T. gondii em galinhas caipiras nessa região.Fil: Camillo, G.. Universidade Federal de Santa Maria; BrasilFil: Machado, M. E. A.. Universidade Federal de Santa Maria; BrasilFil: Cadore, G.C.. Universidade Federal de Santa Maria; BrasilFil: Bräunig, P.. Universidade Federal de Santa Maria; BrasilFil: Venturini, María Cecilia. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; ArgentinaFil: Pardini, Lais Luján. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Barros, L.D.. Universidade Estadual de Londrina; BrasilFil: Garcia, J.L.. Universidade Estadual de Londrina; BrasilFil: Sangioni, L.A.. Universidade Federal de Santa Maria; BrasilFil: Vogel, F.S.F.. Universidade Federal de Santa Maria; Brasi

Annihilation of low energy antiprotons in silicon

The goal of the AE$\mathrm{\bar{g}}$IS experiment at the Antiproton Decelerator (AD) at CERN, is to measure directly the Earth's gravitational acceleration on antimatter. To achieve this goal, the AE$\mathrm{\bar{g}}$IS collaboration will produce a pulsed, cold (100 mK) antihydrogen beam with a velocity of a few 100 m/s and measure the magnitude of the vertical deflection of the beam from a straight path. The final position of the falling antihydrogen will be detected by a position sensitive detector. This detector will consist of an active silicon part, where the annihilations take place, followed by an emulsion part. Together, they allow to achieve 1$$ precision on the measurement of $\bar{g}$ with about 600 reconstructed and time tagged annihilations. We present here, to the best of our knowledge, the first direct measurement of antiproton annihilation in a segmented silicon sensor, the first step towards designing a position sensitive silicon detector for the AE$\mathrm{\bar{g}}$IS experiment. We also present a first comparison with Monte Carlo simulations (GEANT4) for antiproton energies below 5 MeVComment: 21 pages in total, 29 figures, 3 table

Prospects for measuring the gravitational free-fall of antihydrogen with emulsion detectors

The main goal of the AEgIS experiment at CERN is to test the weak equivalence principle for antimatter. AEgIS will measure the free-fall of an antihydrogen beam traversing a moir\'e deflectometer. The goal is to determine the gravitational acceleration g for antihydrogen with an initial relative accuracy of 1% by using an emulsion detector combined with a silicon micro-strip detector to measure the time of flight. Nuclear emulsions can measure the annihilation vertex of antihydrogen atoms with a precision of about 1 - 2 microns r.m.s. We present here results for emulsion detectors operated in vacuum using low energy antiprotons from the CERN antiproton decelerator. We compare with Monte Carlo simulations, and discuss the impact on the AEgIS project.Comment: 20 pages, 16 figures, 3 table

A Wasp Manipulates Neuronal Activity in the Sub-Esophageal Ganglion to Decrease the Drive for Walking in Its Cockroach Prey

BACKGROUND: The parasitoid Jewel Wasp hunts cockroaches to serve as a live food supply for its offspring. The wasp stings the cockroach in the head and delivers a cocktail of neurotoxins directly inside the prey's cerebral ganglia. Although not paralyzed, the stung cockroach becomes a living yet docile 'zombie', incapable of self-initiating spontaneous or evoked walking. We show here that such neuro-chemical manipulation can be attributed to decreased neuronal activity in a small region of the cockroach cerebral nervous system, the sub-esophageal ganglion (SEG). A decrease in descending permissive inputs from this ganglion to thoracic central pattern generators decreases the propensity for walking-related behaviors. METHODOLOGY AND PRINCIPAL FINDINGS: We have used behavioral, neuro-pharmacological and electrophysiological methods to show that: (1) Surgically removing the cockroach SEG prior to wasp stinging prolongs the duration of the sting 5-fold, suggesting that the wasp actively targets the SEG during the stinging sequence; (2) injecting a sodium channel blocker, procaine, into the SEG of non-stung cockroaches reversibly decreases spontaneous and evoked walking, suggesting that the SEG plays an important role in the up-regulation of locomotion; (3) artificial focal injection of crude milked venom into the SEG of non-stung cockroaches decreases spontaneous and evoked walking, as seen with naturally-stung cockroaches; and (4) spontaneous and evoked neuronal spiking activity in the SEG, recorded with an extracellular bipolar microelectrode, is markedly decreased in stung cockroaches versus non-stung controls. CONCLUSIONS AND SIGNIFICANCE: We have identified the neuronal substrate responsible for the venom-induced manipulation of the cockroach's drive for walking. Our data strongly support previous findings suggesting a critical and permissive role for the SEG in the regulation of locomotion in insects. By injecting a venom cocktail directly into the SEG, the parasitoid Jewel Wasp selectively manipulates the cockroach's motivation to initiate walking without interfering with other non-related behaviors

RFID Tracking of Sublethal Effects of Two Neonicotinoid Insecticides on the Foraging Behavior of Apis mellifera

The development of insecticides requires valid risk assessment procedures to avoid causing harm to beneficial insects and especially to pollinators such as the honeybee Apis mellifera. In addition to testing according to current guidelines designed to detect bee mortality, tests are needed to determine possible sublethal effects interfering with the animal's vitality and behavioral performance. Several methods have been used to detect sublethal effects of different insecticides under laboratory conditions using olfactory conditioning. Furthermore, studies have been conducted on the influence insecticides have on foraging activity and homing ability which require time-consuming visual observation. We tested an experimental design using the radiofrequency identification (RFID) method to monitor the influence of sublethal doses of insecticides on individual honeybee foragers on an automated basis. With electronic readers positioned at the hive entrance and at an artificial food source, we obtained quantifiable data on honeybee foraging behavior. This enabled us to efficiently retrieve detailed information on flight parameters. We compared several groups of bees, fed simultaneously with different dosages of a tested substance. With this experimental approach we monitored the acute effects of sublethal doses of the neonicotinoids imidacloprid (0.15–6 ng/bee) and clothianidin (0.05–2 ng/bee) under field-like circumstances. At field-relevant doses for nectar and pollen no adverse effects were observed for either substance. Both substances led to a significant reduction of foraging activity and to longer foraging flights at doses of ≥0.5 ng/bee (clothianidin) and ≥1.5 ng/bee (imidacloprid) during the first three hours after treatment. This study demonstrates that the RFID-method is an effective way to record short-term alterations in foraging activity after insecticides have been administered once, orally, to individual bees. We contribute further information on the understanding of how honeybees are affected by sublethal doses of insecticides

The AEgIS experiment at CERN: Measuring antihydrogen free-fall in earth's gravitational field to test WEP with antimatter

The AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) experiment is designed with the objective to test the weak equivalence principle with antimatter by studying the free fall of antihydrogen in the Earth's gravitational field. A pulsed cold beam of antihydrogen will be produced by charge exchange between cold Ps excited in Rydberg state and cold antiprotons. Finally the free fall will be measured by a classical moir\ue9 deflectometer. The apparatus being assembled at the Antiproton Decelerator at CERN will be described, then the advancements of the experiment will be reported: positrons and antiprotons trapping measurements, Ps two-step excitation and a test-measurement of antiprotons deflection with a small scale moir\ue9 deflectometer

Laser excitation of the n=3 level of positronium for antihydrogen production

We demonstrate the laser excitation of the n = 3 state of positronium (Ps) in vacuum. A combination of a specially designed pulsed slow positron beam and a high-efficiency converter target was used to produce Ps. Its annihilation was recorded by single-shot positronium annihilation lifetime spectroscopy. Pulsed laser excitation of the n = 3 level at a wavelength lambda approximate to 205 nm was monitored via Ps photoionization induced by a second intense laser pulse at lambda = 1064 nm. About 15% of the overall positronium emitted into vacuum was excited to n = 3 and photoionized. Saturation of both the n = 3 excitation and the following photoionization was observed and explained by a simple rate equation model. The positronium's transverse temperature was extracted by measuring the width of the Doppler-broadened absorption line. Moreover, excitation to Rydberg states n = 15 and 16 using n = 3 as the intermediate level was observed, giving an independent confirmation of excitation to the 3 P-3 state

The catatonic dilemma expanded

Catatonia is a common syndrome that was first described in the literature by Karl Kahlbaum in 1874. The literature is still developing and remains unclear on many issues, especially classification, diagnosis, and pathophysiology. Clinicians caring for psychiatric patients with catatonic syndromes continue to face many dilemmas in diagnosis and treatment. We discuss many of the common problems encountered in the care of a catatonic patient, and discuss each problem with a review of the literature. Focus is on practical aspects of classification, epidemiology, differential diagnosis, treatment, medical comorbidity, cognition, emotion, prognosis, and areas for future research in catatonic syndromes

Measuring the free fall of antihydrogen

After the first production of cold antihydrogen by the ATHENA and ATRAP experiments ten years ago, new second-generation experiments are aimed at measuring the fundamental properties of this anti-atom. The goal of AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is to test the weak equivalence principle by studying the gravitational interaction between matter and antimatter with a pulsed, cold antihydrogen beam. The experiment is currently being assembled at CERN's Antiproton Decelerator. In AEGIS, antihydrogen will be produced by charge exchange of cold antiprotons with positronium excited to a high Rydberg state (n > 20). An antihydrogen beam will be produced by controlled acceleration in an electric-field gradient (Stark acceleration). The deflection of the horizontal beam due to its free fall in the gravitational field of the earth will be measured with a moire deflectometer. Initially, the gravitational acceleration will be determined to a precision of 1%, requiring the detection of about 105 antihydrogen atoms. In this paper, after a general description, the present status of the experiment will be reviewed