Lignin is a significant recalcitrant in the conversion of plant biomass to bioethanol. Cinnamyl alcohol dehydrogenase (CAD) and caffeic acid O-methyltransferase (COMT) catalyze key steps in the pathway of lignin monomer biosynthesis. Brown midrib mutants in Zea mays and Sorghum bicolor with impaired CAD or COMT activity have attracted considerable agronomic interest for their altered lignin composition and improved digestibility. We identified candidate genes encoding CAD and COMT enzymes in the grass model species Brachypodium distachyon and developed transgenic plants overexpressing artificial microRNA designed to silence BdCAD1 or BdCOMT4. Both transgenes caused altered flowering time and stem count and weight. Downregulation of BdCAD1 caused a leaf brown midrib phenotype, the first time this phenotype has been observed in a C3 plant. While acetyl bromide soluble lignin measurements were equivalent in BdCAD1-silenced and wildtype plants, histochemical staining and thioacidolysis indicated a decrease in lignin syringyl units and reduced syringyl/guaiacyl ratio in the transgenic plants. BdCOMT4-downregulated plants exhibited a decrease in total lignin content, a significant reduction of guaiacyl lignin, and a modest reduction of syringyl lignin. Ethanol yield by microbial fermentation was enhanced in both BdCAD1- and BdCOMT4-downregulated plants. These results have elucidated two key genes in the lignin biosynthetic pathway in B. distachyon that, when perturbed, may result in greater biomass yield and bioconversion efficiency.

No description available.

La esquizofrenia está considerada un síndrome clínico heterogéneo con una etiopatogenia de origen multifactorial, en el que se incluyen factores ambientales, caracteriales y genéticos. A pesar de que más del 50% de la variabilidad de la enfermedad se puede deber a uno o varios factores genéticos, sólo un número limitado de variantes de riesgo genético y con un efecto muy débil han podido ser identificados. Muchos de ellos no han podido reproducirse tanto por la diversidad de las muestras y poblaciones estudiadas como por su asociación a diversas enfermedades mentales. Parte de esta heterogeneidad ha intentado ser solventada mediante el uso de endofenotipos o fenotipos intermedios y marcadores biológicos, usados como marcadores de vulnerabilidad genética. El gen de la Catecol-O-Metil Transferasa (COMT), que codifica un enzima catabolizador de dopamina en el córtex prefrontal ha sido estudiado como uno de los genes candidatos más prometedores en el estudio de la etiopatogenia de la esquizofrenia, especialmente el polimorfismo rs4680 (COMT Val158Met). La posibilidad de asociar alteraciones en la regulación dopaminérgica prefrontal se encontraría refrendada por la hipótesis dopaminérgica revisada, según la cual, en la esquizofrenia existiría un desequilibrio dopaminérgico, con un incremento en la función dopaminérgica subcortical D2 y un déficit de estimulación D1 cortical. El polimorfismo COMT Val158Met no ha podido confirmar su asociación con esquizofrenia, existiendo en todo caso un riesgo muy débil asociado al alelo hiperfuncionante Val158. El estudio de endofenotipos y marcadores biológicos ha sugerido la asociación del polimorfismo con alteraciones cognitivas, neurofisiológicas, neuroanatómicas y a fenotipos clínicos como agresividad, suicidio, síntomas psicóticos, edad de inicio y respuesta clínica, encontrándose resultados heterogéneos, así como la existencia de una modulación del riesgo de asociación por el consumo de cannabis. Gran parte de la heterogeneidad puede explicarse por problemas metodológicos, relacionados con la validez y representatividad de las muestras, que podrían solventarse con la recogida sistemática de variables en muestras epidemiológicas en fases iniciales de la enfermedad. Partiendo de la hipótesis de la existencia de una alteración dopaminérgica prefrontal en la esquizofenia, el alelo Val158 del gen COMT estaría asociado a una expresión de síntomas psicóticos más graves, especialmente los negativos y a factores de mal pronóstico. Igualmente el consumo de cannabis podría modular este riesgo, incrementando el riesgo o contrarrestando los factores protectores. El objetivo principal fue estudiar la asociación de la presentación clínica y evolución a las seis semanas de tratamiento antipsicótico de pacientes con un primer episodio de psicosis y las variantes del polimorfismo COMT Val158Met así como su interacción con el consumo de cánnabis premórbido. Los objetivos secundarios fueron estudiar la incidencia de esquizofrenia y validar la representatividad de la muestra, analizar la relación entre el polimorfismo Val158Met y sintomatología clínica, edad de inicio, respuesta al tratamiento y estimar la presencia de interacciones gen-ambiente con el consumo de cánnabis premórbido. Para ello, se reclutaron 174 pacientes consecutivos con un primer episodio de psicosis de esquizofrenia, trastorno esquizofreniforme, trastorno esquizoafectivo, trastorno psicótico breve o trastorno psicótico no especificado, incluidos dentro del programa PAFIP, diseñado para la detección y tratamiento de los casos incidentes en la comunidad de Cantabria de Febrero 2001 a Febrero 2005. Los pacientes fueron evaluados con una entrevista semiestructurada, las escalas SANS, SAPS, HDRS, CDS, YMRS y la entrevista SCID-I. Fueron seguidos durante las primeras seis semanas de tratamiento antipsicótico de asignación aleatoria (olanzapina, risperidona o haloperidol). El genotipo del polimorfismo rs4680 se determinó en muestras de sangre venosa. Un primer estudio mostró una incidencia tratada de 1.38/10000 y la asociación de esta incidencia a factores de riesgo como edad menor de 25 años, sexo masculino, estado marital soltero, desempleo nivel educativo primario, ambiente urbano y consumo de cannabis. Un segundo estudio encontró una asociación del alelo Val158 con sintomatología negativa al inicio y edad de inicio temprana, diagnóstico de esquizofrenia y duración de psicosis sin tratar prolongada en mujeres. En un tercer estudio se mostró la asociación del consumo de cánnabis premórbido con edad de inicio más temprana y una interacción entre consumo de cannabis y el genotipo, de modo que el consumo de cannabis contrarresta el efecto protector del alelo 158 Met. Finalmente, en un cuarto estudio se confirmó la persistencia de la asociación del genotipo Val158Met con mayor sintomatología negativa tras seis semanas de tratamiento, no encontrando diferencias en cuanto a la respuesta clínica. Los resultados muestran que el polimorfismo COMT Val158Met pueden estar asociados a una edad de inicio más temprana y una mayor gravedad de síntomas negativos. Del mismo modo, el consumo de cánnabis premórbido se asocia a una menor edad de inicio y se encuentra un patrón de interacción con el polimorfismo, eliminando los efectos protectores del alelo Met158. Los hallazgos sugieren la importancia del polimorfismo COMT Val158Met y del consumo de cannabis en la etiopatogenia de la esquizofrenia, que podría explicarse por la disminución de trasmisión dopaminérgica prefrontal. / The schizophrenia is considered a heterogeneous syndrome which has multifactorial causes, including environmental, characterial and genetic factors. Despite the fact that 50% of the variability of the illness is explained by genetic factors, only a limited number of genetic variants have been identified as weak risk factors. Most of them have not been replicated because of the heterogeneity of the studied samples and the association with other mental illnesses. This variability has been tried to be solved by the use of endophenotypes and biological markers, as indicators of genetic vulnerability. Catechol-O-Methyltransferase gene, that codifies a dopamine degradation enzyme active in prefrontal cortex, has been studied as one of the most promising candidates in the etiopathogenesis of schizophrenia, particularly the rs4860 polymorphism (Val158Met). The possible association with an altered prefrontal dopaminergic transmission would be supported by the revised dopaminergic theory. Following this theory, there is a dopaminergic disequilibrium in schizophrenia, with an increase in subcortical D2 dopaminergic transmission and a deficit in D1 cortical stimulation. COMT Val158Met polymorphism has not consistently associated with schizophrenia. The study of endophenotypes and biological markers has suggested associations with cognitive deficits, neurophysiologic and neuroanatomic markers and with clinical phenotypes, such as aggressiveness, suicide, psychotic symptoms, age of onset and clinical response. It also has been reported an interaction with cannabis in the modulation of the risk of psychosis. This heterogeneity could be explained by methodological biases, related to the validity and representativeness of the studied samples and may be solved with the systematic study of epidemiological samples of patients in the initial phases of psychosis. Following the hypothesis of the existence of an altered prefrontal dopaminergic transmission, the Val158 allele in the COMT gene would be associated with more severe psychotic symptoms, particularly negative symptoms and with poor prognostic factors. Likewise, the premorbid use of cannabis could modulate this risk, increasing the risk or counteract the protective factors. The main objective was to study the association between the clinical onset and evolution in the first 6 weeks of treatment and the COMT Val158Met polymorphism as well as the interaction with premorbid cannabis use. The secondary objectives were to study the incidence of schizophrenia and validate the representativeness of the sample, to analyse the relation between the Val158Met polymorphism and clinical symptoms, age of onset, clinical response to treatment and to estimate the presence of gen-environment interactions with the premorbid cannabis use. 174 consecutive first episode psychosis patients with a diagnosis of schizophrenia, schizoaffective disorder, schizophreniform disorder, brief psychotic disorder or psychosis non-otherwise specified were included in the PAFIP program. The program was designed for the detection and treatment of all cases in the region of Cantabria, form February 2001 to February 2005. The patients were assessed with a semi-structured interview, SANS, SAPS, HDRS, CDS, YMRS scales and the SCID-I interview. They were followed up to 6 weeks and treated with a randomly assigned antipsychotic (olanzapine, risperidone or haloperidol). Rs4680 polymorphism was assessed in peripheric blood samples. A first study showed a treated incidence of 1.38/10000 and the association with several risk factors such as age under 25 years, male gender, single marital status, unemployment, primary educational level, urban environment and cannabis use. A second study found an association between the Val158 allele and negative symptoms severity at onset, early age of onset, schizophrenia diagnosis and longer duration of untreated psychosis in females. A third study showed an association between premorbid cannabis use and early age of onset and an interaction between cannabis use and genotype, indicating that the cannabis use counter act the protective effect of the Met158Met allele in age of onset. Finally, in a fourth study the association between the Val158 allele and negative symptoms was confirmed after 6 weeks of treatment, although no relation was found with clinical response. The results showed that the COMT Val158Met polymorphism could be associated with an earlier age of onset and a higher severity of negative symptoms. Likewise, the premorbid use of cannabis was associated with an earlier age of onset and there was found a gene-environmental interaction, deleting the protective effect of the Met158 Allele. These findings suggest the importance of COMT Val158Met polymorphism and premorbid cannabis use in the etiopathogenesis of the schizophrenia that could be explained by a decrease in the prefrontal dopaminergic transmission.

No description available.

There is a significant comorbidity between anxiety/depression and functional gastrointestinal syndromes, such as irritable bowel syndrome (IBS) and functional dyspepsia. The pathophysiological link between emotions and the gut is not known. A model of an emotional motor system (EMS) which reacts to interoceptive and exteroceptive stress has been proposed. EMS consists of specific brain structures including anterior cingulate cortex (ACC), amygdala, hippocampus and hypothalamus and mediates their communication to the rest of the body (including the gastrointestinal tract) through the hypothalamus-pituitary-adrenal (HPA) axis, the autonomic nervous system (ANS) and by a pain modulation system. The aim of this thesis was to test the EMS model by studying the relationship between symptoms of anxiety and depression and IBS-like symptoms in patients with recurrent unipolar depression, in patients with IBS and in a sample of a normal Swedish population. The peripheral limb of EMS (ANS, HPA axis and the pain modulations system) was tested in patients with IBS and control subjects. Spectral heart rate variability was used to investigate ANS function in patients with refractory IBS and in healthy controls. The HPA axis function was tested by a weight adjusted low dose dexamethasone suppression test in control subjects. The influence of catecholamine degradation on pain modulation was tested by analyzing val158met catechol-o-methyl transferase (COMT) polymorphism in patients with IBS and in control subjects. We found a significant relationship between symptoms of anxiety/depression and IBS-like symptoms in patients with recurrent unipolar depression, in patients with IBS and in a sample of the normal population. Interestingly, patients with recurrent unipolar depression in remission had no more IBS-like symptoms than controls, indicating that the gastrointestinal symptoms may resolve when depression is treated to remission. Patients with IBS have an increased mid-frequency power in rest and in supine position (after tilt test) compared to healthy controls indicating an increased sympathetic ANS drive. The symptoms of diarrhea and early satiety has in the litterature been associated to the stimulation of corticotropin releasing hormone (CRH) receptors and was also in our study related to HPA axis function tested by a low dose dexamethasone test. Interestingly both hypo- and hyperfunction of the HPA axis was related to these symptoms in control subjects. The val158met COMT polymorphism was associated to IBS-like symptoms. Control subjects with IBS-like symptoms (defined by the upper quartile in total GSRS-IBS score) had a higher frequency of the met/met and a significantly lower frequency of the val/met genotype. Also patients with IBS tended to have a lower frequency of the heterozygous val/met genotype so we conclude that this genotype may be protective against IBS/IBS like symptoms. In addition, the val/val genotype in patients with IBS was associated to diarrhea symptoms. Conclusions: Our results support the model of an emotional motor system in the genesis of functional gastrointestinal symptoms by the finding of the association of IBS-like symptoms and mood disturbances, and by finding alterations in the peripheral limbs of EMS (ANS, HPA axis and catecholamines) in subjects with IBS and IBS-like symptoms.

No description available.

Proper neuronal function requires the preservation of appropriate neural excitability. An adaptive increase in neural excitability after exposure to agents that depress neuronal signaling blunts the sedative drug effects upon subsequent drug exposure. This adaptive response to drug exposure leads to changes in drug induced behaviors such as tolerance, withdrawal and addiction. Here I use Drosophila melanogaster to study the cellular and neuronal components which mediate behavioral tolerance to the anesthetic benzyl alcohol. I demonstrate that rapid tolerance to benzyl alcohol is a pharmacodynamic mechanism independent of drug metabolism. Furthermore, tolerance is a cell autonomous response which occurs in the absence of neural signaling. Using genetic and pharmacological manipulations I find the synapse to play an important role in the development of tolerance. In addition, the neural circuits that regulate arousal and sleep also alter benzyl alcohol sensitivity. Beyond previously described transcriptional mechanisms I find a post-translational role of the Ca2+-activated K+-channel, slowpoke in the development of tolerance. Finally, I explore a form of juvenile onset tolerance, which may have origins that differ from rapid tolerance. The implications of this study go beyond tolerance in Drosophila melanogaster to benzyl alcohol and can shed light on human drug tolerance, withdrawal and addiction. / text

Das Ziel der Untersuchungen war einen möglichen Einfluss von Genpolymorphismen auf den postoperativen Verlauf kardiochirurgischer Patienten aufzudecken. Es wurde präoperativ das zu untersuchende Blut entnommen und zentrifugiert. Das überstehende Blutplasma diente der Bestimmung des Catecholaminspiegels mittels HPLC. Aus den korpuskulären Bestandteilen wurde die DNA isoliert und zur Genanalyse verwendet. Die Polymerase-Ketten-Reaktion mit anschließender Schmelzkurvenanalyse ermöglichte eine Differenzierung der 145A>G, 1165G>C β1-Adrenorezeptor- und 472G>A COMT-Polymorphismen. Der postoperative Verlauf der Patienten wurde bis zu deren Entlassung aufgezeichnet. Unter Betrachtung der einzelnen Polymorphismen zeigten sich Unterschiede im postoperativen Noradrenalinverbrauch, im postoperativen Gesamtcatecholaminverbrauch, in der Aufenthaltsdauer im Krankenhaus und im präoperativen Noradrenalinplasmaspiegel. Patienten mit dem 145G/X und 1165CC waren signifikant länger im Krankenhaus als die Träger des 145AA und 1165G/X. Der postoperative Noradrenalinverbrauch und Gesamtcatecholaminverbrauch unterlag der Beeinflussung der drei Polymorphismen. Die Träger des 145G/X, 1165G/X und 472GG hatten einen signifikant höheren Noradrenalinverbrauch als die 145AA, 1165CC und 472A/X Träger. Im zweiten Schritt der Analyse wurden die SNP-Kombinationen berücksichtigt. Es stellte sich heraus, dass sich unter Betrachtung dieser die zuvor festgestellten signifikanten Zusammenhänge auflösten. Demzufolge ist eine Betrachtung der SNP-Kombinationen wichtig um genetische Risiken identifizieren zu können und keine Risiken in Datensätze hinein zu interpretieren.

The development of new high throughput technologies able to multiplex disease biomarkers as well as advances in medical treatments has lead to the recent expansion of the newborn screening panel to include DNA-based targets. Four rare disorders; deletion 22q11.2 syndrome and Spinal Muscular Atrophy (SMA), Severe Combined Immunodeficiency (SCID) and Congenital Cytomegalovirus (CMV), are potential candidates for inclusion to the newborn screening panel within the next few years. The major focus of this study was to determine whether 5’-hydrolysis assays developed for the four distinct disorders with specific detection needs and analytical ranges could be combined on the OpenArray system and in multiplexed qPCR reactions. SNP detection of homozygous SMN1 deletions in SMA, CNV detection in the 22q11.2 critical region, and quantification of the SCID biomarker, T-cell receptor excision circles (TRECs) and CMV were all required for disease confirmation. SMA and 22q11.2 gene deletions were accurately detected using the OpenArray system, a first for the technology. The medium density deletion 22q11.2 multiplex successfully identified deletion carriers having either the larger 3 Mb deletion or the smaller 1.5 Mb deletions. Both TREC and CMV targets were detected but with a decrease in sensitivity when compared to their singleplex counterparts. Lastly, copy number detection of the TBX1 was performed when multiplexed with the TREC assay, without a decrease in detection limit of either assay. Here, we provide proof of principal that qPCR multiplexing technologies are amenable to implementation with a newborn screening laboratory.

Das Ziel der Untersuchungen war einen möglichen Einfluss von Genpolymorphismen auf den postoperativen Verlauf kardiochirurgischer Patienten aufzudecken. Es wurde präoperativ das zu untersuchende Blut entnommen und zentrifugiert. Das überstehende Blutplasma diente der Bestimmung des Catecholaminspiegels mittels HPLC. Aus den korpuskulären Bestandteilen wurde die DNA isoliert und zur Genanalyse verwendet. Die Polymerase-Ketten-Reaktion mit anschließender Schmelzkurvenanalyse ermöglichte eine Differenzierung der 145A>G, 1165G>C β1-Adrenorezeptor- und 472G>A COMT-Polymorphismen. Der postoperative Verlauf der Patienten wurde bis zu deren Entlassung aufgezeichnet. Unter Betrachtung der einzelnen Polymorphismen zeigten sich Unterschiede im postoperativen Noradrenalinverbrauch, im postoperativen Gesamtcatecholaminverbrauch, in der Aufenthaltsdauer im Krankenhaus und im präoperativen Noradrenalinplasmaspiegel. Patienten mit dem 145G/X und 1165CC waren signifikant länger im Krankenhaus als die Träger des 145AA und 1165G/X. Der postoperative Noradrenalinverbrauch und Gesamtcatecholaminverbrauch unterlag der Beeinflussung der drei Polymorphismen. Die Träger des 145G/X, 1165G/X und 472GG hatten einen signifikant höheren Noradrenalinverbrauch als die 145AA, 1165CC und 472A/X Träger. Im zweiten Schritt der Analyse wurden die SNP-Kombinationen berücksichtigt. Es stellte sich heraus, dass sich unter Betrachtung dieser die zuvor festgestellten signifikanten Zusammenhänge auflösten. Demzufolge ist eine Betrachtung der SNP-Kombinationen wichtig um genetische Risiken identifizieren zu können und keine Risiken in Datensätze hinein zu interpretieren.