The Development of The Germ Line During Embryogenesis of Caenorhabditis elegans

Die Prozesse, die bei der Entwicklung der embryonalen Keimbahn entscheidend sind, sind bisher weitgehend unbekannt. In embryonal letalen Mutanten von C. elegans in den Genen cib-1, cib-2 und cib-3 (cib steht für changed identity of blastomeres) geht die Keimbahnidentität in den Keimbahn-Zellen P1, P2 oder P3 verloren. Diese Blastomeren verzögern die Zellteilung und teilen sich dann symmetrisch statt asymmetrisch. Im Rahmen dieser Arbeit wurden Mutanten in allen drei Genen analysiert. cib-1 codiert für die einzige Thymidylat Synthase in C. elegans. Nach einer Inaktivierung der Zellzyklus-Kontrolle teilen sich in cib-1-Embryonen die P-Zellen nicht mehr verzögert. Die dTTP-Synthese ist über die DNA-Integrität und die Zellzyklus-Kontrolle mit der Entwicklung der Keimbahn verbunden. Die Sequenz von cib-3 ist nematodenspezifisch ohne bekannte Funktion. Als Interaktionspartner wurden in einem Yeast-two-Hybrid die konservierten Proteine RACK-1 und eine Cathepsin L Cystein Proteinase identifiziert, die in RNAi-Experimenten den typischen cib-Phänotyp zeigen. CIB-3 beeinflusst die Segregation von keimbahnspezifischen Proteinen wie PIE-1 und somatischen Proteinen wie MEX-5. In cib-3-Embryonen werden beide Proteine nicht verteilt und gelangen bei der Zellteilung in die gleichen Tochterzellen. Als Folge exprimieren die Tochterzellen gleichzeitig somatische und keimbahnspezifische Proteine. cib-2 ist ein bis zum Menschen sehr konserviertes Gen, für das bisher keine Funktion bekannt ist. Die drei cib-Gene sind an zwei verschiedenen, neuen Prozessen beteiligt. Der eine Prozess steuert die Transmission der Zellpolarität in eine cytoplasmatische Polarität für die Segregation keimbahnspezifischer Proteine. Der andere Prozess reguliert die Keimbahnentwicklung mit einer Qualitätskontrolle für die DNA-Integrität. Möglicherweise steuern die beiden Prozesse mit sehr konservierten Proteinen auch in anderen Organismen die Entwicklung einer gesunden Keimbahn.The essential processes for embryonic germ line development are so far largely unknown. In embryonic lethal C. elegans mutants of the genes cib-1, cib-2 and cib-3 (cib means changed identity of blastomeres) is the germ line identity of the germ line cells P1, P2 or P3 lost. These blastomeres show delayed cell divisions and cleave symmetric instead of asymmetric later on. Mutants of all three genes were analysed during this work. cib-1 codes for the only Thymidylate Synthase of C. elegans. After inactivation of the cell cycle control in cib-1-embryos the P cells are not dividing delayed anymore. The synthesis of dTTP is connected with germ line development via DNA integrity and cell cycle control. The sequence of cib-3 is nematode specific without assigned function. In a Yeast-two-Hybrid were the conserved proteins RACK-1 and a Cathepsin L Cystein Proteinase identified as interaction partners, which show the typical cib-phenotype in RNAi-experiments. CIB-3 has an influence on the segregation of germ line specific proteins like PIE-1 and somatic proteins like MEX-5. In cib-3-embryos both proteins are not segregated and locate after the next cell division in the same daughter cells. So these daughter cells express somatic and germ line specific proteins at the same time. cib-2 is highly conserved to human without assigned function. The three genes participate in two different and new processes. The first process controls the transmission of cell polarity to a cytoplasmic polarity, which is essential for the segregation of germ line specific proteins. The second process regulates the germ line development with a quality check for DNA integrity. It is possible that these two processes control with highly conserved proteins the development of a healthy germ line also in other organisms

2 kirja Fr. M. von Klingerile

http://tartu.ester.ee/record=b1847558~S1*es

Effects of a near infrared-reflecting greenhouse roof cover on the microclimate and production of tomato in the tropics

The effects of a shading paint containing NIR-reflecting pigments applied to the roof of an experimental greenhouse on greenhouse microclimate, plant response of a tomato crop and fruit yield and quality were studied under the tropical climate conditions of Central Thailand. One experiment was carried out in the rainy (2006) season and in the dry (2005/2006) season.The maximal reduction of the air temperatures inside the greenhouse with the NIR reflecting roof paint was observed during the dry season. At this time the temperature in this house was 2.8 °C lower than in the control greenhouse without shading paint. On average the temperature reduction was 2 °C in the dry and 0.6 °C in the rainy season. The magnitude of the temperature reduction was influenced by the time of application in relation to stage of plant growth. Cumulative water consumption between the 4th and 17th week after transplanting was reduced by 8.8 % and 6.2 % during the dry and rainyseason, respectively. However, this did not significantly influence overall water use efficiency. Reduction in the transmission of the photosynthetic active radiation did not significantly influence yield. Shading had only negligibly small influence on plant height, number of trusses, leaf area index and dry matter partitioning

Intersubjective action-effect binding: Eye contact modulates acquisition of bidirectional association between our and others’ actions

In everyday social life, we predict others’ actions in response to our own actions.Subsequently, on the basis of these predictions, we control our actions to attain desired social outcomes and/or adjust our actions to accommodate the anticipated actions of the others. Representation of the bidirectional association between our and others’ actions, that is, intersubjective action-effect binding, could make such intersubjective action control easier and smoother. The present study investigated not only whether or not intersubjective action-effect binding was acquired but also whether or not eye contact modulated it. Experiment 1 showed that after a repeated experience during which participants’ finger movements triggered a target female individual’s mouth gesture, observing the target’s mouth gestures came to automatically trigger the participants’finger movements. Experiments 2 and 3 revealed that this effect was not observed when the target’s gaze direction was averted (Experiment 2) or when the target’s eyes were closed (Experiment 3) throughout the acquisition phase. These results indicate that intersubjective action-effect binding occurs and that an ostensive signal, that is, eye contact modulates it

Thermal and optical analysis of a passive heat recovery and storage system for greenhouse skin

The thermal performance of a greenhouse can be greatly affected by the thermal and optical properties of its envelope system. In this study, a novel skin for greenhouse consisting of ethene-co-tetrafluoroethene (ETFE) membrane and Phase Change Material (PCM) RT28 has been developed and has also been experimentally investigated. The optical behaviour of the developed ETFE-Phase Change Material module sample is measured using a spectrometer and a pyranometer, respectively. The results show that at liquid state, the module has higher transmittance than that of at solid state. In addition, the light transmittance is related to the PCM's temperature. In the thermal aspect, the ETFE-Phase Change Material module presents different characterisation under various irradiances. Comparative analysis is also conducted for the ETFE-Phase Change Material, ETFE-water and ETFE alone. The ETFE-Phase Change Material system shows a benefit of the thermal management than that of other systems

Biallelic CACNA2D1 loss-of-function variants cause early-onset developmental epileptic encephalopathy

Voltage-gated calcium (CaV) channels form three sub-families (CaV1-3). The CaV1 and CaV2 channels are heteromeric, consisting of an α1 pore-forming subunit, associated with auxiliary CaVβ and α2δ subunits. The α2δ subunits are encoded in mammals by four genes, CACNA2D1-4. They play important roles in trafficking and function of the CaV channel complexes. Here we report biallelic variants in CACNA2D1, encoding the α2δ-1 protein, in two unrelated individuals showing a developmental and epileptic encephalopathy (DEE). Patient 1 has a homozygous frameshift variant c.818_821dup/p.(Ser275Asnfs*13) resulting in nonsense-mediated mRNA decay of the CACNA2D1 transcripts, and absence of α2δ-1 protein detected in patient-derived fibroblasts. Patient 2 is compound heterozygous for an early frameshift variant c.13_23dup/p.(Leu9Alafs*5), highly likely representing a null allele, and a missense variant c.626G>A/p.(Gly209Asp). Our functional studies show that this amino-acid change severely impairs the function of α2δ-1 as a calcium channel subunit, with strongly reduced trafficking of α2δ-1G209D to the cell surface, and a complete inability of α2δ-1G209D to increase the trafficking and function of CaV2 channels. Thus biallelic loss-of-function variants in CACNA2D1 underlie the severe neurodevelopmental disorder in these two patients. Our results demonstrate the critical importance and non-interchangeability of α2δ-1 and other α2δ proteins for normal human neuronal development

Encoding of amplitude modulations by auditory neurons of the locust: influence of modulation frequency, rise time, and modulation depth

Using modulation transfer functions (MTF), we investigated how sound patterns are processed within the auditory pathway of grasshoppers. Spike rates of auditory receptors and primary-like local neurons did not depend on modulation frequencies while other local and ascending neurons had lowpass, bandpass or bandstop properties. Local neurons exhibited broader dynamic ranges of their rate MTF that extended to higher modulation frequencies than those of most ascending neurons. We found no indication that a filter bank for modulation frequencies may exist in grasshoppers as has been proposed for the auditory system of mammals. The filter properties of half of the neurons changed to an allpass type with a 50% reduction of modulation depths. Contrasting to reports for mammals, the sensitivity to small modulation depths was not enhanced at higher processing stages. In ascending neurons, a focus on the range of low modulation frequencies was visible in the temporal MTFs, which describe the temporal locking of spikes to the signal envelope. To investigate the influence of stimulus rise time, we used rectangularly modulated stimuli instead of sinusoidally modulated ones. Unexpectedly, steep stimulus onsets had only small influence on the shape of MTF curves of 70% of neurons in our sample

Bi-allelic pathogenic variants in HS2ST1 cause a syndrome characterized by developmental delay and corpus callosum, skeletal and renal abnormalities

Heparan sulfate belongs to the group of glycosaminoglycans (GAGs), highly sulphated linear polysaccharides. Heparan sulfate 2-O-sulfotransferase 1 (HS2ST1) is one of several specialized enzymes required for heparan sulfate synthesis and catalyzes the transfer of the sulfate groups to the sugar moiety of heparan sulfate. We report biallelic pathogenic variants in the HS2ST1 gene in four individuals from three unrelated families. Affected individuals showed facial dysmorphism with coarse face, upslanted palpebral fissures, broad nasal tip, and wide mouth, developmental delay and/or intellectual disability, corpus callosum agenesis or hypoplasia, flexion contractures, brachydactyly of hands and feet with broad fingertips and toes, and uni- or bilateral renal agenesis in three individuals. HS2ST1 variants cause a reduction in HS2ST1 mRNA and decreased or absent heparan sulfate 2-O-sulfotransferase 1 in two of three fibroblast cell lines derived from affected individuals. The heparan sulfate synthesized by the individual 1 cell line lacks 2-O-sulfated domains but had an increase in N- and 6-O-sulfated domains demonstrating functional impairment of the HS2ST1. As heparan sulfate modulates FGF-mediated signaling, we found a significantly decreased activation of the MAP kinases ERK1/2 in FGF-2-stimulated cell lines of affected individuals that could be restored by addition of heparin, a GAG similar to heparan sulfate. Focal adhesions in FGF-2-stimulated fibroblasts of affected individuals showed an increased length and concentrated at the cell periphery. Our data demonstrate that a heparan sulfate synthesis deficit causes a novel recognizable syndrome and emphasize a role for 2-O-sulfated heparan sulfate in human neuronal, skeletal and renal development