Cellular and circuit excitability in rodent models of neurodevelopmental disorders

Autism spectrum disorders and intellectual disabilities (ASD/ID) are estimated to a↵ect approximately 3-5% of the population. Genetic factors constitute a major risk factor in ASD/ID, accounting for 40 to 50% of cases, with monogenic forms of syndromic ASD representing 5% of cases. Many of the genetic causes of ASD/ID are thought to share common phenotypes at the cellular level, thus animal models of monogenic forms of ASD/ID provide a valuable tool to better understand the underlying pathophysiology of these disorders. In this thesis I examined two rodent models of monogenic forms of ASD/ID associated with developmental delay, impaired cognitive function and epilepsy, namely CDKL5 deficiency disorder (CDD) and Fragile X Syndrome (FXS). First, I examined synaptic function and intrinsic excitability in the hippocampus of a novel Cdkl5 knock-out (Cdkl5-/y) rat model of CDD. I show an increase in long-term potentiation (LTP) in the hippocampus of Cdkl5-/y rats, consistent to what has previously been reported in mouse models of this disorder. I extend this finding by using a combination of electrophysiological and histological techniques to assess the properties of pre-synaptic neurotransmitter release together with multiple post-synaptic mechanisms that may contribute to the observed Cdk-/y phenotype. Intriguingly, I demonstrated that many of the mechanisms that have been postulated to underlie enhanced LTP are not altered in Cdkl5-/y rats when tested at the single cell level, including changes in AMPAR/NMDAR ratios and increased expression of Ca2+-permeable AMPA receptors. Second, I examined the contribution of the axon initial segment (AIS) to the cellular hyperexcitability of CA1 pyramidal cells in the Fmr1-/y mouse model of FXS. I show that increased AIS length in CA1 pyramidal cells in Fmr1-/y mice is associated with cellular hyperexcitability. I show that depolarisation induced AIS plasticity is unaltered in Fmr1-/y mice is associated with cellular hyperexcitability. I show that depolarisation induced AIS plasticity is unaltered in Fmr1-/y mice, despite an observed reduction in synaptic transmission of EC inputs. In the final chapter of this thesis, I built on my findings in the hippocampus of Fmr1-/y mice, despite an observed reduction in synaptic transmission of EC inputs. In the final chapter of this thesis, I built on my findings in the hippocampus of Fmr1-/y mice. I found the AIS developmental trajectory to be a↵ected in a layer specific manner, with Fmr1-/y mice exhibiting a typical developmental profile in L2/3 and 5 but altered AIS development in L4. However, I did not observe an e↵ect of visual deprivation on AIS length or cellular excitability in either genotype. In summary, this thesis provides insights into the cellular excitability and synaptic physiology in two rodent models of monogenic ASD/ID. I further our existing understanding of rodent models of CDD by characterising hippocampal synaptic and intrinsic physiology in a novel rat model of this disorder, highlighting the need for the identification of robust cross species phenotypes that can be used as potential biomarkers and therapeutic targets in CDD. Furthermore, I put forward the notion of AIS regulation as a contributor to the underpinning of cellular excitability in rodent models of FXS. Additionally, this work contributes to the growing body of evidence showing that compensatory mechanisms have a major contribution to the phenotypes observed in rodent models of ASD/ID, and which should be taken into consideration when developing potential treatment strategies

Influence of material type and surface benzalkonium chloride preconditioning on biofilm formation and activity

This study investigates the potential of benzalkonium chloride (BC), a cationic surfactant, on the prevention of biofilm formation on stainless steel ASI 316 and silicone rubber, two distinct surfaces currently used on food processing facilities. The surfaces were preconditioned with several concentration of BC for 30 min. Treated surfaces were characterized by the sessile drop method, demonstrating that surfactant pre-treatment increased the hydrophobicity of the surfaces, this increase being a function of BC concentration increase applied for preconditioning. In order to ascertain the preventive effect in biofilm formation, the treated surfaces where inserted in a chemostat continuously inoculated with P. fluorescens in the exponential phase of growth, being the biofilm allowed to grow for 6 days. The results showed that BC preconditioning did not prevent or impair biofilm formation. In fact, biofilms developed on the treated surfaces presented higher biomass and respiratory activity than the ones formed on the untreated surfaces, this phenomenon being more evident for silicone than for stainless steel and for surfaces treated with higher BC concentrations. Scanning electron microscopy and biochemical analysis reveal that the difference of surface type and surface preconditioning, by itself, gave rise to the formation of structural and biochemical distinct biofilms. The overall results suggest that preconditioning of stainless steel and silicone rubber surfaces with BC allowed the formation of biofilms with more recalcitrant properties than the ones found on untreated surfaces

Role of benzalkonium chloride surface preconditioning in the increased resistance of biofilms to removal and disinfection

The main goals of the present study was to ascertain the role of surface preconditioning in the biofilm sanitation (removal and disinfection) ability of the cationic surfactant benzalkonium chloride (BC) and to investigated whether BC preconditioning can be a factor of the increased resistance of the Pseudomonas fluorescens biofilms to the surfactant. Prior to biofilm formation, coupons of two distinct materials (stainless steel and silicone rubber) currently used on medical and industrial processing facilities were exposed to several sub-effective concentrations of BC for 30 min. Afterwards, these conditioned coupons were used as the surfaces to form biofilms in a chemostat for 6 days. The antimicrobial action of BC on the biofilms was assessed by means of respiratory activity, due to oxygen consumption, and biofilm mass. The results showed that BC preconditioning, by itself, did not prevent or impair biofilm formation. In general, the mass and respiratory activity of the biofilms developed on the conditioned coupons increased with the increase of the BC concentration used in the preconditioning. The data related with BC application to the bacterial biofilms formed on the conditioned metal and rubber coupons showed that biofilms became more difficult to inactivate, especially those that have been developed in the coupons preconditioned with the higher BC concentrations. Thus, it can be concluded that the antimicrobial ability of BC was considerably disturbed when the surfaces are preconditioned with the surfactant. Based merely on this data, it can be speculated that, in the initial adhesion stage, the contact of the P. fluorescens with the BC residues adsorbed on the coupons surface, due to preconditioning, induces bacteria resistance when they are entrapped in a developed biofilm and submitted to BC aggression.IBQF, and the Portuguese Foundation for Science and Technology (FCT

Covid 19 impacts on digital marketing strategies: the case of catering SMEs in Portugal

Focusing the study's on the implementation of digital marketing strategies by Small and Medium-sized Enterprises (SMEs) in the catering sector in Portugal during the pandemic period COVID 19, the present investigation aims to understand the impact of this pandemic in the implementation of digital marketing strategies of SMEs, to investigate the depth of implementation of these strategies according to the digital marketing decalogue, and to propose a performance matrix for these SMEs that intend to start efforts in this direction. For this purpose, a qualitative study was carried out, using semi-structured interviews, in a sample collected under the snowball technique, composed of 9 SMEs. It was possible to notice that the current pandemic crisis implied changes in how digital marketing strategies are perceived and applied. It was also found that more than strategies, these SMEs adopted isolated initiatives that combine digital marketing strategies and traditional marketing, and it was also possible to proceed with a set of measures to be implemented by these SMEs that intend to start efforts in this direction.info:eu-repo/semantics/publishedVersio

Lâminas de irrigação no primeiro ciclo dos genótipos Prata-anã e Princesa nas condições do Norte de Minas.

O objetivo deste trabalho foi avaliar a resposta produtiva dos genótipos Prata-Anã e Princesa a diferentes lâminas de irrigação. O trabalho foi conduzido no norte de Minas Gerais. Utilizaram-se mudas plantadas nos espaçamento de 2,0 x 2,5 metros. Os tratamentos consistiram de cinco lâminas de irrigação (25%, 50%, 75%, 100% e 125% da evapotranspiração de referência - ETo) e dois genótipos de bananeira (Prata-Anã e Princesa). A lâmina de irrigação foi determinada com base na evaporação do Tanque Classe A. Utilizou-se o delineamento em blocos casualizados com esquema de parcela subdividida com três blocos. A produtividade aumentou linearmente com o aumento da lâmina de irrigação. O genótipo Prata-Anã possui menor ciclo vegetativo, o genótipo Princesa apresenta menor ciclo produtivo e maior produtividade de fruto e não há diferença entre os genótipos para o ciclo total. O ciclo produtivo estimado diminui 11,11% com o aumento da lâmina de irrigação de 25% da ETo para 125% da ETo. O ciclo total estimado diminui 8,82% com o aumento da lâmina de irrigação de 25% da ETo para 125% da ETo. A produtividade de fruto estimada aumenta 35,20% com o aumento da lâmina de irrigação de 25% da ETo para 125% da ETo

Estimativa da área foliar de variedades de cana-de-açúcar no Submédio do Vale do São Francisco.

A utilização do método não destrutivo de fator de forma para estimar a área foliar em cana-de-açúcar (Saccharum officinarum L.) pode apresentar diferenças em decorrência de variedades, tornando-se necessária uma correção no fator de forma recomendado atualmente (0,75). Assim, objetivou-se com este trabalho, determinar fatores de forma para a estimativa de área foliar de variedades de cana-de-açúcar no Submédio do Vale do São Francisco. O experimento foi conduzido na Usina Agrovale S.A., em Juazeiro, BA. Foram coletadas folhas de sete variedades de cana-de-açúcar: RB92579, RB835089, RB72454, SP716949, VAT90212, SP943206 e Q124. Para determinar a área foliar (AF) real foi utilizado o integrador de área foliar. O fator de forma (FF) de cada variedade foi determinado pela razão da área foliar observada pela área do retângulo formado a partir do comprimento e da maior largura da folha, em função da área real. A utilização de fatores de forma específicos garante maior exatidão da estimativa da área foliar das variedades de cana-de-açúcar SP716949, VAT90212, SP943206 e Q124

Comparação entre diferentes formas de fornecer micronutrientes às sementes de feijão.

O presente trabalho teve como objetivo comparar diferentes formas de aplicação dos micronutrientes: Boro (B), Cobalto (Co) e Molibdênio (Mo) em sementes de feijão. As formas de aplicação avaliadas foram: recobrimento de sementes em leito de jorro, recobrimento em sacos plásticos e o fornecimento via sulco

Physicochemical properties of Butter cheese from Marajó manufactured with buffalo milk and cow milk.

This study aimed to evaluate the physicochemical characteristics, texture and color parameters of the artisanal Butter cheese from Marajó, manufactured with partial substitution of buffalo milk for cow milk. Four formulations were elaborated: B100 (100% buffalo milk); B80 (80% buffalo milk + 20% cow milk); B70 (70% buffalo milk + 30% cow milk) and B60 (60% buffalo milk + 40% cow milk). Three replicates were performed. The partial substitution of 20%, 30% and 40% of buffalo milk caused the reduction of fat in 16.2%, 21.6% and 25.4%, and protein in 5.2%, 5.7%, and 6%, respectively, with decrease of elasticity, cohesiveness, gumminess and chewiness, but had no influence on the hardness. Moisture had significant and strongly negative correlation with elasticity, cohesiveness, gumminess and chewiness. Fat and protein had significant and strongly positive correlations with elasticity, cohesiveness, gumminess and chewiness. Significant differences were found for color variables L*, a*, b* and ho. The increase in cow milk concentration increased the yellowgreenish tonality, with an emphasis in yellow tones

Efeito da adição de leite bovino ao leite de búfala nas diferentes características do queijo artesanal do Marajó, tipo creme.

O objetivo do estudo foi comparar os efeitos da substituição parcial do leite bubalino por leite de vaca, nas características físico-químicas, de textura, cor e nos parâmetros sensoriais do queijo artesanal do Marajó tipo Creme, tradicionalmente elaborado com leite de búfala. Quatro queijos foram elaborados com as seguintes formulações: C100 (100% leite de búfala); C80 (80% leite de búfala + 20% leite de vaca); C70 (70% leite de búfala + 30% leite de vaca) e C60 (60% leite de búfala + 40% leite de vaca). Três repetições foram realizadas. Os resultados analíticos da composição (umidade, proteína, gordura, minerais e acidez); dos parâmetros de textura (dureza, elasticidade, coesividade, mastigabilidade) e dos atributos de cor (L*, a*, b*, C*, ho) foram significativamente diferentes entre as formulações. Por outro lado, a presença do leite de vaca não ocasionou alterações nos atributos sensoriais. Com base nos resultados desse estudo, concluiu-se que a adição de até 40% de leite bovino na elaboração do queijo tipo Creme não afeta a sua aceitação pelo consumidor, permitindo um abastecimento do mercado em períodos de entressafra, quando a produção do leite bubalino diminui