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The Getting Ready to Learn (GRTL) program is an early intervention program designed to improve the developmental skills and learning capacity of Native American children in the Northwest Arctic region of Alaska. Early intervention programs have been found to decrease high school dropout rates and increase employment rates, which contribute to better health outcomes in young adulthood. The Northwest Arctic is a remote area that lacks many resources. As such, the people of this region experience various health disparities. The GRTL program was implemented in 7 of the 11 villages in the Northwest Arctic Borough of Alaska (NWABA). The purpose of this thesis was to evaluate the impact the GRTL program may have had on the development skills (communication, gross motor, fine motor, problem solving, social-personal skills) of participating children and reading behaviors of participating caregivers. Two survey instruments were used to evaluate the GRTL program. Specifically, the Ages and Stages Questionnaire (ASQ) measured developmental skills of participating infants and children, and the Parent Questionnaire (PQ) measured caregiver's satisfaction with the program and reading behaviors of caregivers with their child. Interviews with program employees were also conducted to further interpret the results from the surveys. Program employees reported there was significant community support for the GRTL program, and parents were pleased with the program. Parents especially liked having a place that allowed them to focus on their child and believed the atmosphere provided positive socialization opportunities. Key informants also reported barriers to participation, which included harsh weather conditions that limited program participation. The ASQ indicated an increase in the means of development skills on the post-test; although most were not significantly different. The PQ showed a significant increase in reading behaviors from participating caregivers. Overall, the qualitative results suggest the GRTL program had a positive impact on its participating children and caregivers.

This is a historical study of preschool nationally and partly internationally with a focus on elucidating the development of quality elements. The study will trace the beginnings of perkindergaten and how the programs have evolved to their current state. The study contains a look at the current state of prekindergarten programs within the United States and how the differing states are measuring their programs. The use of the word quality is examined as it relates to how programs are designed and implemented. The study will also examine several different states that have been acknowledged as the front runners in prekindergarten education services. The international perspective includes at look at several different countries and how they have implemented their early childhood programs. This is section looks at some of their standards for their programs and the requirements for their teachers. The final part of the study draws conclusions as to how to best proceed when making polices for prekindergarten programs in the United States taking into account the many perspectives.

In this manuscript there a new method that possesses an element of early development of children is introduced. In this case the “game”, that learn pupils of primary school to perform the laboratory work, is suggested. The primary school students are acquainted with the aim of experiments, the order of their performing and the results description. There have performed several examinations of the after performing the laboratory work. Thus, the good development results were achieved. Primary science education in Lithuania is compared with primary education in Sweden.

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No. of bitstreams: 2 Dissertação - Núbia Sousa Carrijo - 2011.pdf: 957612 bytes, checksum: cbe93773d48d1a86e9cbbba954779238 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2011-05-23 / This study was aimed at characterizing the fruit and at observing if its size affects the germination and early development of seedlings of Syagrus oleracea Becc. (Arecaceae), Mineiros and Jataí (GO), measured and separated into five size classes ((T1: fruit≤4,300cm; T2: 4,300cm>fruit≤4,833cm; T3: 4,833cm>fruit≤5,367cm; T4: 5,367cm>fruit ≤5,900cm e T5: fruit>5,900cm).After the fruit collection, the physical analysis of the fruits, the seeds, the embryo and endosperm was made, on different days after sowing (0, 20, 40, 60, 80, 100, 110, 120 and 130 days after sowing). The emergence analysis and of initial development was made individually every 10 days, six evaluations performed. After stabilization of the emergency, all the seedlings were analyzed every 10 days, a total of 16 ratings. In both, in each seedling, the length of insertion to the apex of the leaf and stem diameter at ground level were measured; calculating the speed of emergence index (EVI), emergence percentage (E%) and time spent to emerge half of the fruits (T50). In germination chambers BOD types, trials were carried out with green and ripe fruits and the influence of different wavelengths of visible light in the germination process was verified. In these trials the germination speed index (GSI), germination (%G) and time spent to germinate half of the fruits (T50) were calculated. The descriptive analysis was also performed for the variables related to the size of the fruits and diaspores, followed by analysis of variance and regression equations when necessary for the characteristics evaluated. The fruits measure between 3,61 and 6,98 cm. The greater the thickness of the functional pore, the higher the germination capacity and GVI. The initial seedling development was uniform within 60 days after the stabilization of the emergence for all sizes of fruits; however, the fruit shorter than 5,367 cm higher has better performance between 60 and 150 days after the stabilization of the emergence. In nursery conditions, the higher the fruit, the greater the IVE. In the nursery, higher %E were found in fruits higher than 5.90% cm and lower %E in fruits shorter than 4,30 cm. In the laboratory, higher %G were found in fruits with length between 4,834 and 5,367 cm and lower % G between 5,368 and 5,90 cm. Ripe fruits have a higher germination capacity when compared to green fruits. Guariroba is a neutral species, for it is independent on the influence of light for the germination to occur. / O presente trabalho teve como objetivos caracterizar o fruto e verificar se o tamanho do fruto afeta a germinação e o desenvolvimento inicial das plântulas de Syagrus oleracea Becc. (Arecaceae), conhecida popularmente como guariroba. Para tanto, foram coletados frutos de guariroba nos municípios de Mineiros e Jataí (GO), mensurados e separados em cinco classes de tamanho (T1: fruto≤4,300cm; T2: 4,300cm>fruto≤4,833cm; T3: 4,833cm>fruto≤5,367cm; T4: 5,367cm>fruto ≤5,900cm e T5: fruto>5,900cm). Posteriormente à coleta dos frutos, foi realizada a análise física destes, dos diásporos, do embrião e do endosperma em diferentes dias após semeadura (0; 20; 40; 60; 80; 100; 110; 120 e 130 dias após semeadura). A análise de emergência e desenvolvimento inicial foi realizada individualmente de 10 em 10 dias, sendo realizadas seis avaliações. Após estabilização da emergência, foram analisadas todas as plântulas de 10 em 10 dias, totalizando 16 avaliações. Em ambos, foram medidos, em cada plântula, comprimento da inserção até o ápice da folha e diâmetro do colo ao nível do solo; calculando índice de velocidade de emergência (IVE), porcentagem de emergência (%E) e tempo gasto para emergir metade dos frutos (T50). Em câmaras de germinação tipo BOD foram realizados ensaios com frutos verdes e maduros assim como verificada a influência de diferentes comprimentos de onda da luz visível no processo de germinação, nestes ensaios foram calculados índice de velocidade de germinação (IVG), porcentagem de germinação (%G) e tempo gasto para germinar metade dos frutos (T50). Foi ainda realizada análise descritiva para as variáveis relacionadas ao tamanho dos frutos e diásporos, seguida de análise de variância e as equações de regressão quando necessárias para as características avaliadas. Os frutos medem entre 3,61 e 6,98cm. Quanto maior a espessura do poro funcional maior a capacidade germinativa e IVG. O desenvolvimento inicial das plântulas foi uniforme até 60 dias após a estabilização da emergência para todos os tamanhos de frutos, no entanto os frutos menores que 5,367cm obtiveram maior desempenho entre 60 e 150 dias após a estabilização da emergência. Em condições de viveiro, quanto maior o fruto, maior IVE. No viveiro foram encontradas maiores %E em frutos maiores que 5,90cm e menores %E em frutos menores que 4,30cm. No laboratório, maiores %G foram encontradas em frutos com comprimento entre 4,834 e 5,367cm e menores %G entre 5,368 e 5,90cm. Frutos maduros possuem maior capacidade de germinação quando comparados com frutos verdes. A guariroba é uma espécie neutra, pois independe da influência luminosa para ocorrência da germinação.

La gravité terrestre est une contrainte mécanique fondamentale exercée sur les organismes vivants et contre laquelle nous avons adapté nos stratégies de posture et de locomotion ainsi que toutes les régulations métaboliques et cardiovasculaires. Outre le stimulus mécanique direct, la gravité est mesurée par l'organe vestibulaire, premier système sensoriel à émerger chez les protochordés il y a environ 500 millions d'années, aussi précocement que le système visuel. Le système vestibulaire a alors été asservi aux fonctions d'équilibre et de stabilisation du regard, par des réflexes posturaux et oculaires, fonctions récemment enrichies d’un rôle clé dans la cognition spatiale et sociale chez l’adulte. Ses capacités d’encodage des mouvements de la tête, des accélérations du corps et de la gravité terrestre font de ce système un acteur majeur dans la perception de la verticalité, la navigation, l’orientation et la mémorisation spatiale. Nous avons émis l'hypothèse que la perception sensorielle vestibulaire de la gravité via les otolithes pourrait jouer un rôle crucial non seulement chez l’adulte mais également dans les premières étapes du développement des fonctions sensorimotrices et cognitives. Pour la première fois, nous avons étudié un modèle de souris original (souris Head-tilt, B6Ei.GL-Nox3Het / J) présentant une absence congénitale sélective de gravisenseurs vestibulaires. Les souris présentaient un retard dans l'acquisition des réflexes sensorimoteurs, des capacités d’orientation spatiale par guidage olfactif, d'une communication mère-petits par ultrasons alors que les soins maternels étaient normaux. Un retard dans la locomotion et des troubles hyperactifs avec stéréotypies ont également été montré. Nous démontrons ainsi que le développement des individus sur Terre possède une période critique dépendante de la perception sensorielle vestibulaire de la gravité, au moins entre les jours post-nataux 6 à 10 chez les rongeurs. Les informations otolithiques jouent également un rôle clé chez l’adulte dans les fonctions motrices, les processus mnésiques spatiaux et non spatiaux et dans la régulation émotionnelle. Une corrélation entre ces troubles et le retard développemental a été mis en évidence. Nous travaillons actuellement sur les effets de stimulations sensorielles précoces sur le développement et les fonctions adultes chez la souris Het ainsi que sur la caractérisation structurale et fonctionnelle au niveau cérébral des atteintes développementales et comportementales observées. Les observations chez les souris Het corroborent les symptômes rapportés chez les enfants vestibulo-déficients, soutenant le besoin d'un meilleur dépistage des maladies vestibulaires pendant l'enfance. De manière intéressante, les symptômes de ces souris correspondent à ceux présentés par des modèles murins validés d'autisme et réactualiseraient l’importance de la graviception vestibulaire dans la physiopathologie et la thérapie des troubles du spectre autistique (TSA) et autres maladies neurodégénératives au cours du développement. / Earth’s gravity is a fundamental mechanical constraint for living organisms against which we have adapted our strategies of posture and locomotion as well as all metabolic and cardiovascular regulations. Beyond the mechanical stimulus, the vestibular organ is the first sensory system to emerge in protochordates about 500 million years ago, as early as the visual system, encoding the gravity strength into the brain. The vestibular system has since then been devoted to balance and gaze stabilization supported by postural and ocular reflexes, recently fortified with a key role in spatial and social cognition in adults. Its encoding abilities of head movements, body accelerations and Earth's gravity make this system a major player in the perception of verticality, navigation, orientation and spatial memorization. We have hypothesized that vestibular sensory perception of gravity might play a crucial role not only in adults, but also during the first stages of development in both sensorimotor and cognitive functions. For the first time, we have investigated an original mouse model (Head-Tilt mice, B6Ei.GL-Nox3Het/J) with selective congenital absence of vestibular gravisensors. Our data highlights that mouse pups suffered from a delay in the acquisition of sensorimotor reflexes, spatial olfactive guidance, path integration and ultrasonic communication while maternal care remained normal. In addition, a delay in locomotor development and the appearance of were observed during the late stage of development. We demonstrate that development on Earth has a critical period dependent on the vestibular sensory perception of gravity, at least between postnatal days 6 to 10 in rodents. We have shown that otolithic information plays a key role in the adult motor functions, spatial and non-spatial memory processes, reference frames choice but also in emotional regulation. These disorders have been correlated with early developmental delay. We are currently working on the effects of early sensory stimulation on development and adult functions in our Het mouse model as well as on the structural and functional characterization at the cerebral level of observed developmental and behavioral impairments. Observations in Het mice corroborate with symptoms reported in vestibulo-deficient children, supporting the need for better screening of vestibular diseases during childhood. Remarkably, the symptoms of our vestibulo-congenital deficient mice investigated here matched with the profile of validated mouse models of autism and re-update the significance of vestibular graviception in the physiopathology and therapy of autism spectrum disorders during its development.

It has long been the quest of developmental theorists to understand the mechanisms behind cognitive functioning and the acquisition of language. Studies have identified that there is an interdependent, dialectical relationship between cognitive development and language acquisition. The development of language, in typical populations, is therefore dependent on a baseline cognitive skill, which, once acquired, capacitates the further development of cognition. However, very little is known about this process within atypical populations, particularly those with speech and language impairment. This study examined the relationship between cognitive functioning and early predictive factors in an atypical population of pre-school children with speech and language impairment using three measures of cognitive functioning (as measured by the WPPSI (Wechsler Pre-School and Primary Intelligence Scale), the Griffiths and the JSAIS (Junior South African Individual Scale)) and a range of demographic, diagnostic and early developmental childhood factors. Results identify factors such as parental levels of education, family structure, gender and pregnancy and early childhood health as the main influences of cognitive performance. They also highlight the pervasive influence of speech and language impairment on non-verbal and processing speed abilities. The presence of genetic conditions as well as multiple diagnoses was frequently found to have significant associations with poor cognitive performance. The study also highlighted two things of unexpected interest. The first refers to the role of handedness (particularly undifferentiated handedness) in identifying cognitive difficulty which is related to hemispheric lateralisation, and its relationship to the various diagnostic groups represented within the sample. The second considers the high proportion of diagnostic co-morbidity and the common cognitive profiling patterns across diagnostic categories in abilities outside of the verbal range to highlight potential directions for future research. The implications of these overlaps are considered within existing research on brain laterality, hemispheric dominance and neurological immaturity.

This dissertation concerns the computational modelling of early life development of music perception and cognition. Experimental psychology and neuroscience show results that suggest that the development of musical representations in infancy, whether concerning pitch or rhythm features, depend on exposure both to music and language. Early musical and linguistic skills seem to be, therefore, tangled in ways we are yet to characterize. In parallel, computational modelling has produced powerful frameworks for the study of learning and development. The use of these models for studying the development of music information perception and cognition, connecting music and language still remains to be explored. This way, we propose to produce computational solutions suitable for studying factors that contribute to shape our cognitive structure, building our predispositions that allow us to enjoy and make sense of music. We will also adopt a comparative approach to the study of early development of musical predispositions that involves both music and language, searching for possible interactions and correlations. We first address pitch representation (absolute vs relative) and its relations with development. Simulations have allowed us to observe a parallel between learning and the type of pitch information being used, where the type of encoding influenced the ability of the model to perform a discrimination task correctly. Next, we have performed a prosodic characterization of infant-directed speech and singing by comparing rhythmic and melodic patterning in two Portuguese (European and Brazilian) variants. In the computational experiments, rhythm related descriptors exhibited a strong predictive ability for both speech and singing language variants' discrimination tasks, presenting different rhythmic patterning for each variant. This reveals that the prosody of the surrounding sonic environment of an infant is a source of rich information and rhythm as a key element for characterizing the prosody from language and songs from each culture. Finally, we built a computational model based on temporal information processing and representation for exploring how the temporal prosodic patterns of a specific culture influence the development of rhythmic representations and predispositions. The simulations show that exposure to the surrounding sound environment influences the development of temporal representations and that the structure of the exposure environment, specifically the lack of maternal songs, has an impact on how the model organizes its internal representations. We conclude that there is a reciprocal influence between music and language. The exposure to the structure of the sonic background influences the shaping of our cognitive structure, which supports our understanding of musical experience. Among the sonic background, language's structure has a predominant role in biasing the building of musical predispositions and representations. / Esta tesis aborda la modelización computacional de algunos fenómenos de la percepción y cognición de la música durante el período de desarrollo en la primera infancia. La Psicología experimental y la Neurociencia muestran resultados que sugieren que el desarrollo de las representaciones del ritmo o de la altura musicales durante la infancia son dependientes de la exposición tanto a la música como al lenguaje de las culturas en las que se nace y crece. La capacidad musical y lingüística, durante los primeros años de desarrollo, están inter-relacionadas de formas que aún no ha sido posible caracterizar. En paralelo, las herramientas computacionales proporcionan un marco teórico y empírico eficaz para el estudio del aprendizaje y el desarrollo. El uso de los modelos computacionales para estudiar el desarrollo de la percepción y la cognición de información musical, conectando la música y el lenguaje, todavía queda por explorar. Así, nos proponemos producir soluciones computacionales adecuadas para el estudio de los factores que contribuyen a dar forma a nuestra estructura cognitiva y a la construcción de las predisposiciones que nos permiten disfrutar y dar sentido a la música. También adoptamos una perspectiva comparativa para la investigación que, englobando la música y el lenguaje, busca sus posibles interacciones y correlaciones. Primeramente, hemos abordado la representación de la altura tonal (absoluta vs. relativa) y sus relaciones con el desarrollo. Las simulaciones computacionales han permitido observar que el tipo de codificación utilizada ha influido en la capacidad del modelo para efectuar correctamente una tarea de discriminación, lo cual sugiere una relación entre el aprendizaje y el tipo de información de altura que se utiliza. Seguidamente, se ha realizado una caracterización prosódica del habla y del canto dirigidos al bebé, mediante la comparación de patrones rítmicos y melódicos en dos variantes de Portugués (Europeo y Brasileño). En los experimentos computacionales, los descriptores relacionados con el ritmo han exhibido una fuerte capacidad predictiva para el habla y canto, en tareas de discriminación de variante de lenguaje, siendo observados diferentes patrones rítmicos para cada variante. Se revela que la prosodia del entorno sonoro de un bebé es una fuente rica de información y que el ritmo es un elemento fundamental para la caracterización de la prosodia del lenguaje y las canciones de una cultura. Por último, se construyó un modelo computacional basado en el procesamiento y representación de información temporal para explorar cómo los patrones prosódicos temporales del habla de una cultura específica influyen en el desarrollo de las representaciones y predisposiciones rítmicas. Las simulaciones muestran que la exposición al ambiente sonoro circundante influye en el desarrollo de las representaciones temporales y que la estructura del entorno a que se esta expuesto, específicamente, la falta de canciones maternales, tiene un impacto sobre la forma como el modelo organiza sus representaciones rítmicas internas. Se concluye que existe una influencia recíproca entre la música y el lenguaje. La exposición a la estructura del entorno sonoro influye en la formación de la estructura cognitiva, que sustenta la comprensión de la experiencia musical. De entre todos los “inputs” del entorno sonoro, la estructura del lenguaje tiene una influencia predominante en la construcción de predisposiciones y representaciones musicales.

Title: Maternal Mood and Anxiety Disorders and Child School Readiness: A Manitoba Population-Based Study Objective: This study examined the relationship between several features of maternal Mood/Anxiety – timing, recurrence/persistence and severity – and child development on five key areas of school readiness at kindergarten, controlling for health, demographic and socio-economic factors. Methods: Using administrative data to further understand these relationships at a population level and over time, 18,331mother-child pairs were linked using a unique identifier. Maternal Mood/Anxiety was defined using the number of physician visits for mood and anxiety disorders and the number of prescriptions filled for antidepressants or sedatives/hypnotics. The outcome measures were child scores on five domains of the Early Development Instrument, a population-level tool for determining readiness for school at an aggregate level. Structural equation modeling was used to examine the relationship between maternal Mood/Anxiety and child outcomes for individual time periods, Mood/Anxiety recurrence/persistence and Mood/Anxiety severity. Infant health at birth, the family/socio-economic environment, child age and child gender were also entered into the models. Stratified analysis was undertaken to determine whether SES moderates the relationship between Mood/Anxiety and child outcomes. Results: Maternal Mood/Anxiety had a modest significant negative association with EDI scores, particularly for social, emotional and physical development. Prenatal and recurrent Mood/Anxiety were associated with lower scores on all five outcome domains. The influence of maternal Mood/Anxiety was mediated by the family environment, which had a strong, significant association with the outcomes, particularly for language and cognitive development. Infant health at birth was significantly associated with child outcomes, particularly for physical health. Socio-economic status (SES) was a moderator of the relationship between Mood/Anxiety and child outcomes. Conclusion: Using administrative data to define maternal mood and anxiety disorders is a sensitive measure to detect differences in five key areas of child development, particularly for social, emotional and physical outcomes. Family-related variables had a much stronger relationship with child outcomes than mood and anxiety disorders. Findings from this study can be used to design, implement and evaluate high quality clinical, program and policy interventions to support mothers and families and the healthy development of their children.

Οι πρωτεογλυκάνες αλληλεπιδρούν μεταξύ τους και με άλλα μορφορυθμιστικά μόρια όπως γλυκοπρωτεΐνες και ιντεγκρίνες, καθώς επίσης και με αυξητικούς παράγοντες. Μεγάλο μέρος των ποικίλων λειτουργιών των πρωτεογλυκανών συνδέεται με τις γλυκοζαμινογλυκανικές αλυσίδες (GAGs) τους. Για να μελετήσουμε τη λειτουργία των πρωτεογλυκανών κατά την ανάπτυξη του πρώιμου εμβρύου όρνιθας χρησιμοποιήσαμε το β-D-xyloside, έναν εξειδικευμένο αναστολέα της βιοσύνθεσης των πρωτεογλυκανών και ειδικότερα της πρόσδεσης των αλυσίδων γλυκοζαμινογλυκανών στον πρωτεϊνικό κορμό των πρωτεογλυκανών. Χαμηλές συγκεντρώσεις β-xyloside που είναι γνωστό ότι αναστέλλουν την προσθήκη θειϊκής χονδροϊτίνης αλλά όχι της θειϊκής ηπαράνης στον πρωτεϊνικό κορμό, αποτελούν ένα χρήσιμο εργαλείο για τη μελέτη του ρόλου των πρωτεογλυκανών. Τα πρότυπα των πρωτεϊνών στα έμβρυα που μεταχειρίστηκαν με β-xyloside έδειξαν μετατόπιση των ραδιενεργών κορυφών σε μικρότερη μοριακή μάζα που φαίνεται να οφείλεται στη μείωση του μεγέθους πρωτεογλυκανών. Ήταν αξιοσημείωτο στα αποτελέσματά μας ότι το β-xyloside μετέβαλλε τη μορφή της πρωτεογλυκάνης θειϊκής χονδροϊτίνης decorin προς χαμηλότερα μοριακά βάρη ενώ δε φάνηκε να επηρεάζει το μέγεθος της πρωτεογλυκάνης θειϊκής ηπαράνης perlecan. Στα έμβρυα που μεταχειρίστηκαν με β-xyloside περισσότερη πρωτεϊνη συντέθηκε στα έμβρυα του σταδίου ΧΙΙ (μορίδιο), σε σχέση με αυτά του σταδίου ΗΗ2 (αρχή πρωτογενούς αύλακας/πρώιμο γαστρίδιο), συγκρινόμενα με τα αντίστοιχα έμβρυα μάρτυρες. Αυτό θα μπορούσε να αντανακλά μια επιταχυνόμενη κινητοποίηση και/ή μια μετάφραση των ωογενετικών μεταγράφων στα έμβρυα του σταδίου ΧΙΙ, όταν διαταράχτηκε ο μεταβολισμός των πρωτεογλυκανών. Η απορρύθμιση πρωτεογλυκανών, τροποποιώντας τη λειτουργικότητα και επηρεάζοντας το επίπεδο έκφρασής τους, είχε ως αποτέλεσμα την αδυναμία του πρώιμου εμβρύου να δομήσει την εξωκυττάρια ύλη φυσιολογικά. Το αποτέλεσμα ήταν η κατάρρευση της τυπικής αρχιτεκτονικής του πρώιμου εμβρύου στα πειράματά μας. Πρωτεογλυκάνες θειϊκής χονδροϊτίνης φαίνεται να χρειάζονται για την οργάνωση του σταδίου του βλαστιδίου της όρνιθας. Για την επαγωγή του νευρικού συστήματος φάνηκε να χρειάζονται πρωτεογλυκάνες θειϊκής χονδροϊτίνης/δερματάνης που έχουν συγκεντρωθεί από το στάδιο πριν την έναρξη των μορφογενετικών κινήσεων της γαστριδίωσης και η συνεχής βιοσύνθεση των πρωτεογλυκανών είναι απαραίτητη για τη μορφογένεση του νευρικού σωλήνα. Μελετήσαμε επίσης το πρότυπο κατανομής της συνδετικής πρωτεϊνης πρωτεογλυκανών με ανοσοφθορισμό και ανοσοκατακρήμνιση και το ρόλο αυτής της γλυκοπρωτεϊνης με τη χρήση αντισωμάτων έναντι αυτής. Η συνδετική πρωτεΐνη μεσολαβεί στην πρόσδεση στο υαλουρονικό οξύ πρωτεογλυκανών όπως οι aggrecan, neurocan, versican και brevican δημιουργώντας σταθερά σύμπλοκα στην εξωκυττάρια ύλη. Η αναγνώριση των μορφών της συνδετικής πρωτεΐνης 1 (LP1, 48kDa) και συνδετικής πρωτεΐνης 2 (LP2, 44kDa) στο πρώιμο έμβρυο ήταν επίσης ένα ενδιαφέρον εύρημα των πειραμάτων μας. Είναι γνωστό ότι συνδυασμοί των LP1 και LP2 δημιουργούν πιο σταθερά σύμπλοκα απ’ ότι μόνο του το καθένα από τα δύο μόρια αυτά. Αυτό φαίνεται και από τα πειράματά μας που δείχνουν ότι η aggrecan (180kDa) φαίνεται να συν-κατακρημνίζεται με τις συνδετικές πρωτεΐνες LP1 και LP2. Τα πειράματα ανοσοφθορισμού έδειξαν ότι η συνδετική πρωτεΐνη αρχίζει να εκφράζεται στο στάδιο του βλαστιδίου και επιδεικνύει μια διαφορική έκφραση χωρο-χρονικά κατά την ανάπτυξη του πρώιμου εμβρύου υποδεικνύοντας ότι είναι σημαντική στην κυτταρική μετανάστευση και διαφοροποίηση κυττάρων και στη μορφογένεση ιστών και οργάνων. Αυτό επιβεβαιώθηκε και από τη μελέτη του ρόλου της, στην επόμενη σειρά πειραμάτων μας με τη χρήση μονοκλωνικού αντισώματος έναντι αυτής. Η αναστολή της λειτουργίας της συνδετικής πρωτεϊνης με τη χρήση αντισωμάτων έναντι αυτής έδειξε ότι αυτή η πρωτεϊνη φαίνεται να είναι σημαντική στην οργάνωση της νευρικής πλάκας και τη μορφογένεση του νευρικού σωλήνα, στη μορφογένεση του καρδιακού σωλήνα, του εντέρου, στο σχηματισμό της ραχιαίας αορτής και στην επιθηλιοποίηση των σωμιτών. / Proteoglycans participate in cellular interactions via modulating the effects of growth factors or with other mechanisms in early embryo. The majority of the functions of proteoglycans are associated with the glycosaminoglycan (GAG) chains. We used β-D-xyloside, an inhibitor of proteoglycan synthesis and specifically of GAG attachment to proteoglycan core proteins, to study proteoglycan functions in early chick embryo development. Low concentrations of β-xyloside which are known to affect differentially chondroitin but not heparan sulfate proteoglycan biosynthesis have provided a convenient tool for altering proteoglycan production. The protein patterns of xyloside-treated embryos showed a shift of radioactive peaks to lower molecular mass which could be attributed to the reduction of proteoglycan size as was demonstrated by chondroitinase ABC/AC II treatments. It was notable in our data that β-xyloside altered the chondroitin sulfate proteoglycan decorin to lower molecular mass while it did not seem to affect the size of the heparin sulfate proteoglycan perlecan. More protein was synthesized from xyloside-treated embryos at stage XII (morula) than from embryos at stage HH2 (initial primitive streak/early gastrula) when compared to the controls. This could have reflected an accelerated translation and/or mobilization of oogenetic transcripts in embryos at stage XII when proteoglycan metabolism was disrupted. Misregulation of proteoglycans by modulating the functionality of the protein and by influencing their expression level resulted in an inability of the early embryo to assemble a stable extracellular matrix that would have been normally produced. These changes were associated with the collapse of the typical blastula architecture and inhibition of the induction of mesoderm in the chick embryo. Induction of neuroectoderm required proteoglycans assembled before the initiation of gastrulation movements. However, sustained proteoglycan biosynthesis was required for the morphogenetic movements to form the neural tube and the rest of the embryonic axis. We also studied the spatiotemporal distribution pattern of link protein by immunofluorescence and immunoprecipitation and the role of this glycoprotein by blocking antibodies in the early chick embryo. The recognition of the link protein 1 (LP1, 48 kDa) and link protein 2 (LP2, 44 kDa) types was an important finding of our study. Link protein links several proteoglycans, such as aggrecan to hyaluronan, creating stable aggregates in the extracellular matrix and has a general function in the organization of the extracellular matrix. It is known that combinations of LP1 and LP2 create more stable complexes than the individual link protein molecule. This was also shown in our experiments, in that aggrecan (180kDa) co-precipitated with LP1 and LP2. Our immunofluorescent experiments showed that link protein expression was first detectable at the blastula stage (st. XIII) and its presence may be fundamental as the first extracellular matrix starts to assemble before the initiation of the first major cellular migrations during the gastrula stage. Link protein influorescence was strong in the cells ingressing through the primitive streak and in the migrating cells in embryos at stage HH3 (intermediate streak/mid-gastrula). At stage HH4 (definitive streak/late gastrula), link protein fluorescence was strong at the apical surface of the neural plate. At stage HH4-5 (head process), link protein fluorescence was strong at the apical surface of the neural folds, notochord and endoderm. At stage HH13 (19 somites), link protein fluorescence was intense in the encephalic vesicles, in the extracellular matrix, in the lumen of encephalic vesicles, intense in migrating neural crest cells, neural tube and in notochord, strong in gut lower wall, hard tube and dorsal aorta wall, intense in dermomyotome and strong in sclerotome in somites. By stage HH17 (29 somites), link protein fluorescence was strong in neuroepithelium and extracellular matrix in the lumen of the diencephalon, strong in neural crest cells, in the intraretinal space in the eye, in myocardium and endocardium, in dorsal aorta, in dermomyotome, the outer surface of pharyngeal arches wall of aortic arches and intense in thyroid rudiment. Inhibition of function of link protein by blocking antibodies showed that link protein was important in neuroepithelial tissue organization and neural tube closure, in normal differentiation of the neural tube to form the brain, in the morphogenesis of the heart tube, the dorsal aorta and gut and in somite epithelialization.