TY - THES A1 - Arvidsson, Samuel Janne T1 - Identification of growth-related tonoplast proteins in Arabidopsis thaliana T1 - Identifizierung von wachstumsrelevanten Tonoplast-Proteinen in Arabidopsis thaliana (Ackerschmalwand) N2 - In a very simplified view, the plant leaf growth can be reduced to two processes, cell division and cell expansion, accompanied by expansion of their surrounding cell walls. The vacuole, as being the largest compartment of the plant cell, plays a major role in controlling the water balance of the plant. This is achieved by regulating the osmotic pressure, through import and export of solutes over the vacuolar membrane (the tonoplast) and by controlling the water channels, the aquaporins. Together with the control of cell wall relaxation, vacuolar osmotic pressure regulation is thought to play an important role in cell expansion, directly by providing cell volume and indirectly by providing ion and pH homestasis for the cytosoplasm. In this thesis the role of tonoplast protein coding genes in cell expansion in the model plant Arabidopsis thaliana is studied and genes which play a putative role in growth are identified. Since there is, to date, no clearly identified protein localization signal for the tonoplast, there is no possibility to perform genome-wide prediction of proteins localized to this compartment. Thus, a series of recent proteomic studies of the tonoplast were used to compile a list of cross-membrane tonoplast protein coding genes (117 genes), and other growth-related genes from notably the growth regulating factor (GRF) and expansin families were included (26 genes). For these genes a platform for high-throughput reverse transcription quantitative real time polymerase chain reaction (RT-qPCR) was developed by selecting specific primer pairs. To this end, a software tool (called QuantPrime, see http://www.quantprime.de) was developed that automatically designs such primers and tests their specificity in silico against whole transcriptomes and genomes, to avoid cross-hybridizations causing unspecific amplification. The RT-qPCR platform was used in an expression study in order to identify candidate growth related genes. Here, a growth-associative spatio-temporal leaf sampling strategy was used, targeting growing regions at high expansion developmental stages and comparing them to samples taken from non-expanding regions or stages of low expansion. Candidate growth related genes were identified after applying a template-based scoring analysis on the expression data, ranking the genes according to their association with leaf expansion. To analyze the functional involvement of these genes in leaf growth on a macroscopic scale, knockout mutants of the candidate growth related genes were screened for growth phenotypes. To this end, a system for non-invasive automated leaf growth phenotyping was established, based on a commercially available image capture and analysis system. A software package was developed for detailed developmental stage annotation of the images captured with the system, and an analysis pipeline was constructed for automated data pre-processing and statistical testing, including modeling and graph generation, for various growth-related phenotypes. Using this system, 24 knockout mutant lines were analyzed, and significant growth phenotypes were found for five different genes. N2 - Sehr vereinfacht gesagt kann Blattwachstum auf zwei Prozesse reduziert werden, Zellteilung und Zellexpansion, gefolgt von Zellwandexpansion. Die Vakuole, das größte Organell der Zelle, übt durch die Kontrolle des Wasserhaushaltes der Pflanze eine wichtige Funktion im Zusammenhang mit der Zellexpansion aus. Dies geschieht durch die Regulierung des osmotischen Druckes, durch Import und Export von organischen und anorganischen Ionen über die Vakuolenmembran (den Tonoplast) und durch die Kontrolle ihrer Wasserkanäle (der Aquaporine). Es wird angenommen, dass die Regulierung des vakuolären osmotischen Druckes eine große Rolle bei der Zellexpansion spielt, da der osmotische Druck die Stärke der mechanischen Kraft des Tonoplast auf die Plasmamembran und die Zellwand bestimmt. In dieser Dissertation wird die Rolle von Tonoplastproteinen und ihrer Gene auf die Zellexpansion anhand der Modellpflanze Arabidopsis thaliana (Ackerschmalwand) untersucht, und Kandidaten für wachstumsrelevante Gene werden identifiziert. Da bisher noch kein Signal für die Lokalisierung von Proteinen im Tonoplast identifiziert wurde, gibt es keine Möglichkeit, genomweite Voraussagen über solche Proteinlokalisierungen zu machen. Daher haben wir eine Reihe von aktuellen Proteom-Studien genutzt, um eine Liste von 117 Genen, die für transmembrane tonoplastproteinkodierende Gene kodieren, zusammenzustellen. Zusätzlich wurden andere wachstumsrelevante Gene und Zellzyklus-Gene in die Liste aufgenommen (38 Gene). Die Expression der Gene während der Blattentwicklung sollte mittels einer sensitiven Technik, der quantitativen Polymerasekettenreaktion (qPCR), untersucht werden. Um rasch die für dieses Verfahren notwendigen Oligonukleotide zu entwerfen, wurde ein Computerprogramm („QuantPrime“) entwickelt. Das Programm entwirft automatisch solche Oligonukleotide und überprüft deren Spezifizität in silico auf Ebene der Transkriptome und Genome um Kreuz-Hybridisierungen zu vermeiden, die zu unspezifischen Amplifikationen führen würden. Die qPCR-Plattform wurde in einer Expressions-Studie eingesetzt, um wachstumsrelevante Gen-Kandidaten zu identifizieren. Um wachstumsaktive und nichtaktive Prozesse vergleichen zu können, wurden Proben von unterschiedlichen Bereichen des Blattes zu unterschiedlichen Wachstumsstadien beprobt. Eine musterbasierte Expressionsdatenanalyse wurde eingesetzt, um die Gene hinischtlich ihrer Assoziation mit der Blattexpansionen in eine Rangordnung zu bringen. Die Gene mit dem höchsten Rang wurden als Kandidaten für weitere Experimente ausgewählt. Um die funktionelle Beteiligung dieser Gene auf einer makroskopischen Ebene zu untersuchen, wurden Knockout-Mutanten für die Gen-Kandidaten hinsichtlich ihres Wachstums analysiert. Zu diesem Zweck wurde ein System für die automatisierte Phänotypisierung des Blattwachstums etabliert. Zum einen wurde ein Programm-Paket für detaillierte Annotation von Wachstumsstadien und zum anderen ein Analyse-Paket für automatisierte Datenvorbereitung und statistische Tests entwickelt. Das Analyse-Paket erlaubt die Modellierung und graphische Darstellung verschiedener wachstumsrelevanter Phänotypen. Mit Hilfe dieses Systems wurden 24 Knockout-Mutanten untersucht und signifikante Phänotypen wurden für fünf verschiedene Gene gefunden. KW - Ackerschmalwand KW - Wachstum KW - Tonoplast KW - qPCR KW - Phänotypisierung KW - Arabidopsis KW - Growth KW - Tonoplast KW - qPCR KW - Phenotyping Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-52408 ER - TY - JOUR A1 - Hermanussen, Michael A1 - Scheffler, Christiane A1 - Groth, Detlef A1 - Aßmann, Christian T1 - Height and skeletal morphology in relation to modern life style JF - Journal of physiological anthropology N2 - Height and skeletal morphology strongly relate to life style. Parallel to the decrease in physical activity and locomotion, modern people are slimmer in skeletal proportions. In German children and adolescents, elbow breadth and particularly relative pelvic breadth (50th centile of bicristal distance divided by body height) have significantly decreased in recent years. Even more evident than the changes in pelvic morphology are the rapid changes in body height in most modern countries since the end-19th and particularly since the mid-20th century. Modern Japanese mature earlier; the age at take-off (ATO, the age at which the adolescent growth spurt starts) decreases, and they are taller at all ages. Preece-Baines modelling of six national samples of Japanese children and adolescents, surveyed between 1955 and 2000, shows that this gain in height is largely an adolescent trend, whereas height at take-off (HTO) increased by less than 3 cm since 1955; adolescent growth (height gain between ATO and adult age) increased by 6 cm. The effect of globalization on the modern post-war Japanese society ("community effect in height") on adolescent growth is discussed. KW - Pelvic breadth KW - Elbow breadth KW - Growth KW - Adult height KW - Community effect in height Y1 - 2015 U6 - https://doi.org/10.1186/s40101-015-0080-4 SN - 1880-6805 VL - 34 PB - BioMed Central CY - London ER - TY - JOUR A1 - Schroeder, Florian A1 - Lisso, Janina A1 - Obata, Toshihiro A1 - Erban, Alexander A1 - Maximova, Eugenia A1 - Giavalisco, Patrick A1 - Kopka, Joachim A1 - Fernie, Alisdair R. A1 - Willmitzer, Lothar A1 - Muessig, Carsten T1 - Consequences of induced brassinosteroid deficiency in Arabidopsis leaves JF - BMC plant biology N2 - Background: The identification of brassinosteroid (BR) deficient and BR insensitive mutants provided conclusive evidence that BR is a potent growth-promoting phytohormone. Arabidopsis mutants are characterized by a compact rosette structure, decreased plant height and reduced root system, delayed development, and reduced fertility. Cell expansion, cell division, and multiple developmental processes depend on BR. The molecular and physiological basis of BR action is diverse. The BR signalling pathway controls the activity of transcription factors, and numerous BR responsive genes have been identified. The analysis of dwarf mutants, however, may to some extent reveal phenotypic changes that are an effect of the altered morphology and physiology. This restriction holds particularly true for the analysis of established organs such as rosette leaves. Results: In this study, the mode of BR action was analysed in established leaves by means of two approaches. First, an inhibitor of BR biosynthesis (brassinazole) was applied to 21-day-old wild-type plants. Secondly, BR complementation of BR deficient plants, namely CPD (constitutive photomorphogenic dwarf)-antisense and cbb1 (cabbage1) mutant plants was stopped after 21 days. BR action in established leaves is associated with stimulated cell expansion, an increase in leaf index, starch accumulation, enhanced CO2 release by the tricarboxylic acid cycle, and increased biomass production. Cell number and protein content were barely affected. Conclusion: Previous analysis of BR promoted growth focused on genomic effects. However, the link between growth and changes in gene expression patterns barely provided clues to the physiological and metabolic basis of growth. Our study analysed comprehensive metabolic data sets of leaves with altered BR levels. The data suggest that BR promoted growth may depend on the increased provision and use of carbohydrates and energy. BR may stimulate both anabolic and catabolic pathways. KW - Brassinosteroids KW - Arabidopsis KW - Tricarboxylic acid cycle KW - Biomass KW - Cell expansion KW - Growth Y1 - 2014 U6 - https://doi.org/10.1186/s12870-014-0309-0 SN - 1471-2229 VL - 14 PB - BioMed Central CY - London ER - TY - JOUR A1 - Clegg, Mark R. A1 - Gaedke, Ursula A1 - Böhrer, Bertram A1 - Spijkerman, Elly T1 - Complementary ecophysiological strategies combine to facilitate survival in the hostile conditions of a deep chlorophyll maximum JF - Oecologia N2 - In the deep, cooler layers of clear, nutrient-poor, stratified water bodies, phytoplankton often accumulate to form a thin band or "deep chlorophyll maximum" (DCM) of ecological importance. Under such conditions, these photosynthetic microorganisms may be close to their physiological compensation points and to the boundaries of their ecological tolerance. To grow and survive any resulting energy limitation, DCM species are thought to exhibit highly specialised or flexible acclimation strategies. In this study, we investigated several of the adaptable ecophysiological strategies potentially employed by one such species, Chlamydomonas acidophila: a motile, unicellular, phytoplanktonic flagellate that often dominates the DCM in stratified, acidic lakes. Physiological and behavioural responses were measured in laboratory experiments and were subsequently related to field observations. Results showed moderate light compensation points for photosynthesis and growth at 22A degrees C, relatively low maintenance costs, a behavioural preference for low to moderate light, and a decreased compensation point for photosynthesis at 8A degrees C. Even though this flagellated alga exhibited a physiologically mediated diel vertical migration in the field, migrating upwards slightly during the day, the ambient light reaching the DCM was below compensation points, and so calculations of daily net photosynthetic gain showed that survival by purely autotrophic means was not possible. Results suggested that strategies such as low-light acclimation, small-scale directed movements towards light, a capacity for mixotrophic growth, acclimation to low temperature, in situ exposure to low O-2, high CO2 and high P concentrations, and an avoidance of predation, could combine to help overcome this energetic dilemma and explain the occurrence of the DCM. Therefore, corroborating the deceptive ecophysiological complexity of this and similar organisms, only a suite of complementary strategies can facilitate the survival of C. acidophila in this DCM. KW - DCM KW - Photosynthesis KW - Growth KW - Behaviour KW - Phytoplankton Y1 - 2012 U6 - https://doi.org/10.1007/s00442-011-2225-4 SN - 0029-8549 VL - 169 IS - 3 SP - 609 EP - 622 PB - Springer CY - New York ER -