<p>  </p> <p>Plants synthesize and release a variety of volatile organic compounds (VOCs) that are important for their reproduction, defense, and communication. These low-molecular-weight, lipophilic molecules also serve as practical products in industries such as food additives, fragrances, colorants, nutraceuticals, and pharmaceuticals. In addition, they have agricultural applications such as sustainable methods for pest control. Therefore, identifying the biological mechanisms involved in volatile emission could help researchers develop new ways to control the timing and release of volatiles, defend against pests, and engineer the production of these valuable chemicals.</p> <p>While progress has been made in understanding plant volatile biosynthesis, their release from the cell remains incomplete. For plant VOCs to be emitted into the environment, they must move from their site of biosynthesis through the cytosol, transverse the plasma membrane, hydrophilic cell wall, and sometimes cuticle to exit the cell. It was previously shown by mathematical modeling that to achieve observed emission rates solely by diffusion, VOCs would accumulate in the cellular membranes to levels that are likely detrimental to the membrane integrity and function. Hence, it was proposed that there are biological mechanisms involved to lower VOC concentrations in membranes. In this work, we focus on the aqueous cell wall, the thickest layer among the three subcellular barriers that should act as a barrier for the diffusion of VOCs. We hypothesize that the transport of VOCs across the cell wall is facilitated by lipid transfer proteins (LTPs) which enhance the solubility of hydrophobic volatiles in the aqueous environment, prevent their back partition into the plasma membrane after entering the cell wall, and hence enhance their net diffusion. To investigate if the presence of LTPs has influence on the total VOC efflux, we use reverse-genetic, biochemical, and mathematical modeling approaches. Out of three highly expressed LTPs identified in the petunia petal, only downregulation of <em>PhLTP3</em> expression led to a decrease in VOC emission in the corresponding transgenic plants. A facilitated diffusion model was built to quantify the VOC flux difference with the presence of LTPs in the cell wall. Modeling of the steady state system revealed the facilitation of VOC flux by LTPs is greatest when the VOC concentration gradient across the cell wall is shallow, which is a physiologically relevant condition. In addition, there exists an optimal protein dissociation constant value for maximal facilitated flux, indicating the balance between the binding and the unloading of VOC is critical. With the in vitro displacement assay, the binding constants of candidate PhLTPs with VOCs were obtained and were all found to be in the µM range, which is close to our model predicted optimal value. The results revealed that LTPs, specifically PhLTP3, play a role in the export of VOCs from the plasma membrane, across the cell wall, to the cuticle.</p> <p>In our earlier mathematical model, the emission of VOCs from the petunia flowers was modeled assuming negligible mass transfer resistance on the surface of the cuticle because of their high volatility. However, the resistance imposed by the surface boundary layer was not considered. To examine if surface convection influences VOC emission, a model system which utilized a model cuticular wax film containing 2-phenylethanol (2-PE) was built to imitate the VOC emission from plant cuticle. The convection mass transfer coefficient of 2-PE emission from a model cuticular wax film was obtained by experimental data fitting and calculated from the correlation that involves Sherwood number. The obtained values that were smaller than unity indicates that the surface boundary layer imposes a higher mass transfer resistance than the model cuticle for the emission of 2-PE in the range of wind velocities investigated. The examination of petunia flowers under air flow showed increases in total emission but no significant differences in total internal pools, which indicates an increase in biosynthesis. The emission changes of individual compounds were different and does not clearly correlate to any molecular properties of the compounds.  </p>

Challenges in the South African education system arise from inter alia inadequate training, social and environmental problems, parental inefficiency, insufficient professionalism among teachers, as well as negative attitudes of learners. An urgent need exists to establish “a moral underground, an army of volunteers” (Jansen, 2012) who would be willing to provide another chance to “abandoned children” in poorer schools to develop their full potential for a brighter future. To assist learners to achieve a better future, this study focused on teacher-students and to enhance their learning experiences and consequently their teaching performance. By motivating the teacher-students to develop their potential in order to achieve better, they could, in turn, break the barriers of mediocrity in the learners they taught. The aim of this study was to uncover how a social network service (SNS) like Facebook could be used as an academic tool to support and enhance the affective learning experience of open distance teacher-students in the rural Eastern Cape. The main research question which guided this study was: How can the affective learning of open distance learning teacher-students in the rural Eastern Cape be supported through academic Facebook? The research intervention which elicited data, comprised coaching and scaffolding of the learning content relating to research methodology, as well as guiding the participants to engage with an SNS as a learning technology in an academic environment. The researcher created a support group on Facebook where participants could, at any time, interact with peers and the facilitator. Non-probability purposive sampling selected the participants according to the following criteria: isiXhosa home language speaking teacher-students from the rural areas around Queenstown in the Eastern Cape, enrolled with NWU for a BEd Honours degree, and who owned cellular phones which could connect to the Internet. While 74 teacher-students were invited to participate in the research, only 34 attended some of the coaching and scaffolding sessions, and 22 joined the FaceFunda group page. This qualitative bounded case study was conducted from a postmodern pragmatic view. Data were collected through individual interviews, a focus group interview, text from the FaceFunda group page and the researcher’s reflective diary. The data were analysed with Atlas. ti™. Three patterns emerged which described participants’ affective experiences: (i) emotions while learning with technology, (ii) experiences with technology, and (iii) need for support. In each case, the patterns related to emotions of competence (codes that captured positive and enabling experiences), and emotions of incompetence (codes that captured negative and incapacitating experiences). A secondary analysis of the findings uncovered the guidelines for the academic use of Facebook for rural distance teacher-students. Four themes emerged as guidelines: i) coaching and scaffolding support, (ii) technological support, (iii) peer support, and (iv) communication with the higher education institution. The guidelines highlighted that the affective learning of open distance learning of rural teacher-students in the Eastern Cape can be supported through the academic use of Facebook. ODL teacher-students require support coaching and scaffolding in order to adopt the use of SNSs for academic purposes. Adult learners should be supported to overcome technophobia to enable engagement with learning content. With adequate supportive measures, SNSs can contribute towards positive learning experiences of rural students. / MEd (Learner support), North-West University, Potchefstroom Campus, 2014

Challenges in the South African education system arise from inter alia inadequate training, social and environmental problems, parental inefficiency, insufficient professionalism among teachers, as well as negative attitudes of learners. An urgent need exists to establish “a moral underground, an army of volunteers” (Jansen, 2012) who would be willing to provide another chance to “abandoned children” in poorer schools to develop their full potential for a brighter future. To assist learners to achieve a better future, this study focused on teacher-students and to enhance their learning experiences and consequently their teaching performance. By motivating the teacher-students to develop their potential in order to achieve better, they could, in turn, break the barriers of mediocrity in the learners they taught. The aim of this study was to uncover how a social network service (SNS) like Facebook could be used as an academic tool to support and enhance the affective learning experience of open distance teacher-students in the rural Eastern Cape. The main research question which guided this study was: How can the affective learning of open distance learning teacher-students in the rural Eastern Cape be supported through academic Facebook? The research intervention which elicited data, comprised coaching and scaffolding of the learning content relating to research methodology, as well as guiding the participants to engage with an SNS as a learning technology in an academic environment. The researcher created a support group on Facebook where participants could, at any time, interact with peers and the facilitator. Non-probability purposive sampling selected the participants according to the following criteria: isiXhosa home language speaking teacher-students from the rural areas around Queenstown in the Eastern Cape, enrolled with NWU for a BEd Honours degree, and who owned cellular phones which could connect to the Internet. While 74 teacher-students were invited to participate in the research, only 34 attended some of the coaching and scaffolding sessions, and 22 joined the FaceFunda group page. This qualitative bounded case study was conducted from a postmodern pragmatic view. Data were collected through individual interviews, a focus group interview, text from the FaceFunda group page and the researcher’s reflective diary. The data were analysed with Atlas. ti™. Three patterns emerged which described participants’ affective experiences: (i) emotions while learning with technology, (ii) experiences with technology, and (iii) need for support. In each case, the patterns related to emotions of competence (codes that captured positive and enabling experiences), and emotions of incompetence (codes that captured negative and incapacitating experiences). A secondary analysis of the findings uncovered the guidelines for the academic use of Facebook for rural distance teacher-students. Four themes emerged as guidelines: i) coaching and scaffolding support, (ii) technological support, (iii) peer support, and (iv) communication with the higher education institution. The guidelines highlighted that the affective learning of open distance learning of rural teacher-students in the Eastern Cape can be supported through the academic use of Facebook. ODL teacher-students require support coaching and scaffolding in order to adopt the use of SNSs for academic purposes. Adult learners should be supported to overcome technophobia to enable engagement with learning content. With adequate supportive measures, SNSs can contribute towards positive learning experiences of rural students. / MEd (Learner support), North-West University, Potchefstroom Campus, 2014

Doctor of Philosophy / Department of Counseling and Educational Psychology / Fred O. Bradley / The number of animal training programs in correctional facilities has increased in the past 25 years. Anecdotal accounts have informally assessed the efficacy of prison training programs; however, only limited systemic studies have been conducted (Britton & Button, 2005; Furst, 2006). Preliminary information from anecdotal accounts and narratives indicates the potential these programs have to impact inmate behavior, self- esteem, staff and inmate morale, and community perceptions of offenders (Cushing & Williams, 1995; Harkrader, Burke, & Owen, 2004). There is also an indication inmate trainers learn responsibility, patience, coping skills, and vocational skills (Britton & Button, 2005; Merriam-Arduini, 2000; Turner, 2007). This qualitative study presents preliminary findings from the following five participant perspectives on the perceived outcomes of a canine training program in a correctional facility where inmates train assistance, therapy, rescue, and medical alert canines: (a) inmate trainers, (b) former inmate trainers, (c) non-trainer inmates who are not involved in the training program, (d) staff, and (e) the researcher. Once trained, the canines are adopted as assistance dogs for individuals in need. Data collected from in- depth interviews with current inmate trainers, former inmate trainers, non-trainer inmates, and staff, and audio and video recordings, researcher observations, and a researcher developed scale indicated the following themes which emerged from the study: there are positive emotional outcomes and positive practical outcomes for inmate trainers who work with dogs in the training program. Positive emotional outcomes for inmate trainers include the following: (a) providing social support, (b) gaining a sense of pride, (c) serving as a feeling of giving back to society, (d) increasing personal patience, (e) humanizing the inmate trainers, and (f) improving self-esteem. Positive practical outcomes for inmate trainers emerged in the following areas: (a) improving responsibility, (b) having a positive impact on the prison environment, (c) providing opportunities to help others, (d) using goal setting, (e) gaining employability skills, and (e) having a positive effect on behavior. Results from this study will add to existing literature and research in the field of animal-assisted interventions and rehabilitation programs with human beings, specifically those in correctional facilities. In addition, results from this study will assist correctional administration in the design, implementation, and evaluation of dog training programs in prisons.

O transporte de &#945;-metil glicosídio ( &#945;-MG) em Saccharomyces cerevisiae foi recentemente reportado como transporte ativo, do tipo simporte de &$945;-MG com H+ mediado pela permease Agt1p. A cepa AP77-11B (cepa selecionada em nosso laboratório) 14C-&#945;-MG pelo mecanismo descrito como difusão facilitada porque não existe co-transporte de H+ durante o transporte de &#945;-MG. Os genes HXT1-HXT17 pertencem à família dos transportadores de hexoses em Saccharomyces cerevisiae. Então, nós decidimos investigar a possibilidade que o transporte de &#945;-MG poderia ser mediado pelos transportadores de hexoses. Nós demonstramos que cepa MC966A (tipo selvagem), KY73 (isogênica com MC966A mas deletada nos HXT1-7), BSY08 (isogênica com KY73 com o AGT1 deletado), BSY09 (isogênica com MC966A com o AGT1 deletado) e a EBY.VW4000 (hxt1-17 agt1 gal2-null), não cresceram em &#945;-MG como fonte de carbono. Além disso, estas cepas não transportaram &#945;-MG por difusão facilitada quando as células foram cultivadas em meio com maltose, levando-nos a concluir que os transportadores de hexoses não estavam envolvidos no transporte de &#945;-MG. Nós observamos que a cepa AP77-11B apresentou alta atividade de &#945;-metilglicosidase periplásmica quando as células foram cultivadas em &#945;-MG. Esta atividade enzimática foi ensaiada usando um método descrito primeiramente para invertase periplásmica, no qual as células eram incubadas com fluoreto de sódio, um inibidor da enolase, antes da incubação com &#945;-MG. Então, a glicose produzida durante a hidrólise do -MG poderia ser determinada. A atividade extracelular só está presente em células cultivadas em -&#945;MG. Células de-reprimidas não mostraram atividade de alpha-metilglicosidase. Os parâmetros cinéticos determinados para &#945;-metilglicosidase, indicaram que esta enzima tem baixa afinidade para o alpha-MG. Além do mais, a atividade específica da alpha-metilglicosidase periplásmica aumentou ao longo da curva de crescimento em &#945;-MG. Os resultados reportados mostraram que existem duas vias de utilização de &#945;-MG em Saccharomyces cerevisiae. Uma via é mediada pela Agt1p, responsável pelo transporte ativo de &#945;-MG. Na outra via, a &#945; -metilglicosidase é secretada para o espaço periplásmico das células. Então, a glicose produzida pela hidrólise do &#945;-MG é transportada pelos transportadores de hexoses por difusão facilitada. / Alpha-Methyl glucoside ( alpha-MG) transport in Saccharomyces cerevisiae was previously reported to be an active transport, a H+ -symport mediated by the Agt1p permease. Strain AP77-11B (a strain obtained in our laboratory) takes up 14C- alpha-MG by a mechanism which was ascribed to be facilitated diffusion since there is no H+-cotransport during the alpha-MG uptake. The HXT1-HXT17 there is no H genes belong to a family of hexose transporters in Saccharomyces cerevisiae. Therefore, we decided to investigate the possibility that -MG transport could be mediated by hexose transporters. We demonstrated that strains MC966A (w.t.), KY73 (isogenic to MC966A but hxt1-hxt7-null), BSY08 (isogenic to KY73 with AGT1 deleted), BSY09 (isogenic to MC966A with AGT1 deleted) and even strain EBY.VW4000 (hxt1-hxt17 agt1 gal2-null), were not able to grow on alpha-MG as the sole carbon source. Moreover, none of them presented alpha-MG transport by facilitated diffusion when the strains were grown on maltose leading us to conclude that the HXT glucose transporters were not involved in alpha-MG transport. We found that strain AP77-11B displayed a high periplasmic alpha-methylglucosidase activity when cells were grown on alpha-MG. This enzymatic activity was assayed using a method first described for periplasmic invertase in which cells were incubated with sodium fluoride, an inhibitor of enolase, prior to the incubation with alpha-MG. Then the glucose produced during alpha-MG hydrolysis could be accurately measured. The extracellular activity was present only in cells grown on alpha-MG. Glucose derepressed cells did not show periplasmic alpha-methylglucosidase activity.

As drogas facilitadoras de crime (DFC) são uma série de substâncias químicas que permitem o ato sexual e/ou roubo com pouca ou nenhuma resistência da vítima. Benzodiazepínicos, gama-hidroxibutirato (GHB), cetamina e etanol são clássicas DFC, porém outras substâncias também têm sido utilizadas. Devido às diferentes classes de DFC e a necessidade de métodos sensíveis, a determinação dessas substâncias é um desafio aos toxicologistas forenses. A proposta do estudo foi desenvolver métodos analíticos para determinação principais analitos alvos de DFC para benzodiazepínicos, cetamina e GHB em amostras de urina. Esta matriz biológica é considerada uma amostra não-invasiva e apresenta um período de detecção maior que o sangue. A preparação das amostras foi avaliada através de microextração em fase líquida (LPME) e extração líquido-líquido (LLE). A LPME é uma técnica de extração de drogas que utiliza menor quantidade de solventes orgânicos, maior praticidade e possibilidade de obtenção de altos valores de recuperação. Os analitos foram determinados por cromatografia gasosa acoplada à espectrometria de massas (GC-MS). A LPME validada para benzodiazepínicos e seus produtos de biotransformação exigiu uma combinação de solventes e dupla derivatização para atingir a sensibilidade exigida, enquanto o método para determinação de cetamina, norcetamina e deidronorcetamina utilizou óleo essencial de eucalipto como meio extrator, caracterizando-se um procedimento ecologicamente correto com alta sensibilidade. A extração de GHB foi efetiva por LLE com redução da quantidade de solvente e tempo de análise sem o prejuízo na sensibilidade. Em geral, os métodos desenvolvidos neste trabalho são sensíveis e confiáveis para todos os analitos relatados e conclui-se que a LPME é uma técnica de preparo de amostra eficiente, versátil de baixo custo. Estas condições permitem que sua implementação em qualquer laboratório de análises toxicológicas, podendo ser aplicada em situações de DFC ou de qualquer outra natureza. / Drug-facilitated crime (DFC) are a series of chemicals that allow the sexual act and/or theft with little or no resistance from the victim. Benzodiazepines, gamma-hydroxybutyrate (GHB) and ketamine and ethanol are considered classic DFC, however other substances were also used as the DFC. Due to the different classes of DFC and the need for sensitive methods, the determination of these substances is a challenge to forensic toxicologists. The purpose of this study was to develop analytical methods for determination of the main target analytes of DFC for benzodiazepines, ketamine and GHB in urine samples. This biological matrix is considered a non-invasive sample and shows a larger window of detection than blood. Sample preparation was assessed using liquid phase microextraction (LPME) and liquid-liquid extraction (LLE). The LPME is a drug extraction technique that uses less organic solvents, greater practicality and possibility of obtaining high recovery values. The analytes were determined by gas chromatography - mass spectrometry (GC-MS). The validated LPME technique for benzodiazepines and their metabolites required a combination of solvents and double derivatization to achieve the required sensitivity, while the ketamine, norketamine and dehydronorketamine method used essential oil of eucalyptus as solvent, characterizing a green chemistry approach with high sensitivity. The extraction of GHB was effective by LLE with a reduced amount of solvent and the analysis time without loss in sensitivity. In general, the methods developed in this work using GC-MS are sensitive and reliable for all analytes reported and LPME technique showed to be an efficient sample preparation, versatile and low cost. These conditions allow LPME implementation in any laboratory of toxicological analysis and it can be applied in situations of DFC or any other kind of analysis.

As drogas facilitadoras de crime (DFC) são uma série de substâncias químicas que permitem o ato sexual e/ou roubo com pouca ou nenhuma resistência da vítima. Benzodiazepínicos, gama-hidroxibutirato (GHB), cetamina e etanol são clássicas DFC, porém outras substâncias também têm sido utilizadas. Devido às diferentes classes de DFC e a necessidade de métodos sensíveis, a determinação dessas substâncias é um desafio aos toxicologistas forenses. A proposta do estudo foi desenvolver métodos analíticos para determinação principais analitos alvos de DFC para benzodiazepínicos, cetamina e GHB em amostras de urina. Esta matriz biológica é considerada uma amostra não-invasiva e apresenta um período de detecção maior que o sangue. A preparação das amostras foi avaliada através de microextração em fase líquida (LPME) e extração líquido-líquido (LLE). A LPME é uma técnica de extração de drogas que utiliza menor quantidade de solventes orgânicos, maior praticidade e possibilidade de obtenção de altos valores de recuperação. Os analitos foram determinados por cromatografia gasosa acoplada à espectrometria de massas (GC-MS). A LPME validada para benzodiazepínicos e seus produtos de biotransformação exigiu uma combinação de solventes e dupla derivatização para atingir a sensibilidade exigida, enquanto o método para determinação de cetamina, norcetamina e deidronorcetamina utilizou óleo essencial de eucalipto como meio extrator, caracterizando-se um procedimento ecologicamente correto com alta sensibilidade. A extração de GHB foi efetiva por LLE com redução da quantidade de solvente e tempo de análise sem o prejuízo na sensibilidade. Em geral, os métodos desenvolvidos neste trabalho são sensíveis e confiáveis para todos os analitos relatados e conclui-se que a LPME é uma técnica de preparo de amostra eficiente, versátil de baixo custo. Estas condições permitem que sua implementação em qualquer laboratório de análises toxicológicas, podendo ser aplicada em situações de DFC ou de qualquer outra natureza. / Drug-facilitated crime (DFC) are a series of chemicals that allow the sexual act and/or theft with little or no resistance from the victim. Benzodiazepines, gamma-hydroxybutyrate (GHB) and ketamine and ethanol are considered classic DFC, however other substances were also used as the DFC. Due to the different classes of DFC and the need for sensitive methods, the determination of these substances is a challenge to forensic toxicologists. The purpose of this study was to develop analytical methods for determination of the main target analytes of DFC for benzodiazepines, ketamine and GHB in urine samples. This biological matrix is considered a non-invasive sample and shows a larger window of detection than blood. Sample preparation was assessed using liquid phase microextraction (LPME) and liquid-liquid extraction (LLE). The LPME is a drug extraction technique that uses less organic solvents, greater practicality and possibility of obtaining high recovery values. The analytes were determined by gas chromatography - mass spectrometry (GC-MS). The validated LPME technique for benzodiazepines and their metabolites required a combination of solvents and double derivatization to achieve the required sensitivity, while the ketamine, norketamine and dehydronorketamine method used essential oil of eucalyptus as solvent, characterizing a green chemistry approach with high sensitivity. The extraction of GHB was effective by LLE with a reduced amount of solvent and the analysis time without loss in sensitivity. In general, the methods developed in this work using GC-MS are sensitive and reliable for all analytes reported and LPME technique showed to be an efficient sample preparation, versatile and low cost. These conditions allow LPME implementation in any laboratory of toxicological analysis and it can be applied in situations of DFC or any other kind of analysis.

This thesis reports on the development of a generic online system to support learning and teaching at the University of Melbourne. New online technologies, the fostering of innovation at national and university levels and my position within a central educational unit provided the opportunity in 1996 to adapt a previous software package for online use. My observations of the problematic nature of computer-facilitated learning (CFL) production led me to take an open approach to the development, seeking both a practical product and enhanced understanding. A series of formative questions defined the scope and goals of the study, which were to: *produce a generic online learning system; *increase understanding of the workplace experience of that development; and *develop an organisational model for the further development of generic CFL systems. Given this multi-disciplinary focus, many paradigms in the literature could potentially have guided the study. A number of these aligning with the research purposes, context and constructivist philosophy of the study, were reviewed from the perspectives of learning, CFL development and the organisation.

La Communication facilitée (CF), méthode d'écriture accompagnée, pose des questions scientifiques de validité en étant confondue avec la Psychophanie, méthode dérivée et pratiquée en France, ne permettant pas de distinguer qui écrit. Pour identifier l'origine des messages produits en CF et en Psychophanie, il faut distinguer aussi clairement que possible ces deux méthodes. En filmant avec deux caméras les mains et les visages de six facilités, jeunes adultes autistes non verbaux lors de leurs séances habituelles, nous expérimentons progressivement une modulation du soutien psychomoteur et observons que, par exemple, Amar et Brice présentent chacun séparément des corrélations entre comportements, situations et textes écrits dans plus de cinquante extraits vidéo. Nous observons aussi que Brice et Carine, facilités par la même facilitante, ont produit en 14 séances, des phrases dont le nombre n’est pas significativement différent mais dont les durées sont significativement différentes. Dans la seconde partie nous pratiquons des tests de capacité de lecture avec Brice puis de passage de message (message passing procédure) positifs avec sa facilitante et enfin de modulation du soutien avec une instrumentation accélérométrique. L'observation en vidéo de corrélations multimodales, les tests comportementaux en facilitation, les mesures temporelles et accélérométriques nous montrent, en CF, une contribution discernable des facilités qui devient moins ou non discernable en Psychophanie confirmant la nécessité de distinguer la CF, où le facilité contrôle, au moins en partie, le processus d’écriture sur le plan visuo-moteur, de la Psychophanie où le facilité semble ne rien contrôler. / An augmentative and alternative communication method, Facilitated Communication (FC), raises serious questions regarding origin and therefore credibility of the texts produced by persons having autism. This controversy is partly due to confusion between two methods of facilitation: Facilitated Communication and Psychophany (a method derived from FC and mostly used in France). The present exploratory study aims at identifying origin of the messages produced via FC and Psychophany, and at differentiating these two methods. We first analyze systematically clinical video observations of 6 young non-verbal adults with autism, while practicing FC during regular sessions with their facilitators, and while modulating the psychomotor support of the subjects. Fine video analyses from 2 subjects show 39 clear clinical correlations between behaviors and texts are extracted from 7 sessions in one adult (Brice) and 20 correlations from 4 sessions in another adult Amar. Besides, when comparing two subjects, Brice and Carine, who are facilitated by the same facilitator, we show that the number of sentences produced do not differ significantly, whereas the total time of writing differs significantly. In the second study, Brice and his facilitator are studied more deeply through various tests, reading tests, message passing procedure and psychophysical tests using an accelerometer. Results seem to confirm our first ones showing a contribution of the subject, Brice, to the writing process. Our study confirms necessity distinguishing FC, during which the subjects partly control the writing process at visuo-motor levels, from Psychophany where the subjects apparently do not control anything.

O transporte de &#945;-metil glicosídio ( &#945;-MG) em Saccharomyces cerevisiae foi recentemente reportado como transporte ativo, do tipo simporte de &$945;-MG com H+ mediado pela permease Agt1p. A cepa AP77-11B (cepa selecionada em nosso laboratório) 14C-&#945;-MG pelo mecanismo descrito como difusão facilitada porque não existe co-transporte de H+ durante o transporte de &#945;-MG. Os genes HXT1-HXT17 pertencem à família dos transportadores de hexoses em Saccharomyces cerevisiae. Então, nós decidimos investigar a possibilidade que o transporte de &#945;-MG poderia ser mediado pelos transportadores de hexoses. Nós demonstramos que cepa MC966A (tipo selvagem), KY73 (isogênica com MC966A mas deletada nos HXT1-7), BSY08 (isogênica com KY73 com o AGT1 deletado), BSY09 (isogênica com MC966A com o AGT1 deletado) e a EBY.VW4000 (hxt1-17 agt1 gal2-null), não cresceram em &#945;-MG como fonte de carbono. Além disso, estas cepas não transportaram &#945;-MG por difusão facilitada quando as células foram cultivadas em meio com maltose, levando-nos a concluir que os transportadores de hexoses não estavam envolvidos no transporte de &#945;-MG. Nós observamos que a cepa AP77-11B apresentou alta atividade de &#945;-metilglicosidase periplásmica quando as células foram cultivadas em &#945;-MG. Esta atividade enzimática foi ensaiada usando um método descrito primeiramente para invertase periplásmica, no qual as células eram incubadas com fluoreto de sódio, um inibidor da enolase, antes da incubação com &#945;-MG. Então, a glicose produzida durante a hidrólise do -MG poderia ser determinada. A atividade extracelular só está presente em células cultivadas em -&#945;MG. Células de-reprimidas não mostraram atividade de alpha-metilglicosidase. Os parâmetros cinéticos determinados para &#945;-metilglicosidase, indicaram que esta enzima tem baixa afinidade para o alpha-MG. Além do mais, a atividade específica da alpha-metilglicosidase periplásmica aumentou ao longo da curva de crescimento em &#945;-MG. Os resultados reportados mostraram que existem duas vias de utilização de &#945;-MG em Saccharomyces cerevisiae. Uma via é mediada pela Agt1p, responsável pelo transporte ativo de &#945;-MG. Na outra via, a &#945; -metilglicosidase é secretada para o espaço periplásmico das células. Então, a glicose produzida pela hidrólise do &#945;-MG é transportada pelos transportadores de hexoses por difusão facilitada. / Alpha-Methyl glucoside ( alpha-MG) transport in Saccharomyces cerevisiae was previously reported to be an active transport, a H+ -symport mediated by the Agt1p permease. Strain AP77-11B (a strain obtained in our laboratory) takes up 14C- alpha-MG by a mechanism which was ascribed to be facilitated diffusion since there is no H+-cotransport during the alpha-MG uptake. The HXT1-HXT17 there is no H genes belong to a family of hexose transporters in Saccharomyces cerevisiae. Therefore, we decided to investigate the possibility that -MG transport could be mediated by hexose transporters. We demonstrated that strains MC966A (w.t.), KY73 (isogenic to MC966A but hxt1-hxt7-null), BSY08 (isogenic to KY73 with AGT1 deleted), BSY09 (isogenic to MC966A with AGT1 deleted) and even strain EBY.VW4000 (hxt1-hxt17 agt1 gal2-null), were not able to grow on alpha-MG as the sole carbon source. Moreover, none of them presented alpha-MG transport by facilitated diffusion when the strains were grown on maltose leading us to conclude that the HXT glucose transporters were not involved in alpha-MG transport. We found that strain AP77-11B displayed a high periplasmic alpha-methylglucosidase activity when cells were grown on alpha-MG. This enzymatic activity was assayed using a method first described for periplasmic invertase in which cells were incubated with sodium fluoride, an inhibitor of enolase, prior to the incubation with alpha-MG. Then the glucose produced during alpha-MG hydrolysis could be accurately measured. The extracellular activity was present only in cells grown on alpha-MG. Glucose derepressed cells did not show periplasmic alpha-methylglucosidase activity.