Under alkaline conditions hydrogen peroxide can be used either as a 1ignin-degrading or a 1ignin-preserving bleaching agent. If heavy metal ions are present and/or silicate is absent in the reaction medium, hydrogen peroxide decomposes via hydroxyl radicals and superoxide ions to oxygen and water. These decomposition products are able to react for example with phenolic lignin structures and thereby cause a partial degradation of lignin. In such a system peroxide could act as a bleaching and delignifying agent at the same time and these properties can be utilized for the bleaching of chemical pulps.In order to elucidate the factors which influence the degradation of phenolic structures by oxidation with alkaline hydrogen peroxide the lignin model compounds-methylsyringyl alcohol was studied.By determining the first order reaction rate constants for the oxidation, the main results which were obtained indicate that phenolic lignin structures can be efficiently degraded especially if:A. The pH in the bleaching liquor is close to the pK -valueàfor hydrogen peroxide.B. The ionic strength in the bleaching medium is as high as possible.C. A fixed amount of heavy metal ions (manganese) is added to the bleaching liquor.In the presence of silicate and diethylentriaminepenta-acetic acid (DTPA) hydrogen peroxide is stabilized against decomposition. Under these conditions alkaline hydrogen peroxide is able to react only with lignin units containing conjugated carbonyl groups such as quinone, aryl-oe-carbonyl and cinnamaldehyd structures, leading to an elimination of the chromophoric structures without any substantial dissolution of lignin. In this part of work we have elucidated the kinetic behavior and the reaction products from lignin model compounds of the aryl-of- carbonyl and cinnamaldehyde types.1,2-Diarylpropan-1,3,-diol structures constitute an important building unit in native lignins. We have demonstrated that under hydrogen peroxide bleaching conditions the model compound 2,3--bis(4-hydroxy-3-methoxyphenyl)-3-ethoxy-propanol was converted to stilbenes, ûe. structures which when present in pulps may contribute to a rapid yellowing. The results obtained with model compounds under simulated lignin retaining bleaching conditions demonstrate that there are possibilities to improve the bleaching of mechanical pulps with hydrogen peroxide if:A. The remaining heavy metal ions complexed with DTPA are present in their lowest valence states.B. The concentration of hydroperoxy ions can be maintained at a high level at the lowest possible pH-value. / digitalisering@umu

Suitable orchard land in regions of high elevation, arid climates, and alkaline soil conditions is becoming more limited due to urban sprawl. With the loss of suitable farmland, increasing input costs, and the lack of sound fertility information for these regions, fruit growers face challenges in producing high quality fruit to meet local and general market demand. The question that arises is whether fruit growers can supply sufficient quantities of quality fruit to take full advantage of local and global demand. Government data for population, fruit production, and fruit consumption in Utah were reviewed to determine the potential size of the local market, and determine whether growers have opportunities to increase production to meet unsatisfied demand for high quality local produce. In addition to market analysis, fertility-based management strategies are needed to optimize yield and fruit quality in production areas of high elevation, arid climates, and alkaline soils. Three different approaches were used to investigate the effect of phosphorus (P) and potassium (K) on tart cherry fruit quality and yield at high elevations, arid climate conditions, and in alkaline soils. The approaches of this study include: a rate-response evaluation using the industry-standard Triple-16 fertilizer (16-16-16), and comparison of P and K fertilizer formulations to determine the most cost effective sources of these nutrients with regard to yield and fruit quality. Additions of P and K maintained adequate yield and fruit quality, but showed no significant difference among treatments, where historically aggressive nutrient management had been practiced. Fertilizer additions did result in a significant increase in yield and fruit quality where nutrient management programs were historically much less aggressive. There is no advantage of higher cost fertilizer formulations over standard low-cost sources (i.e.; Triple-16). Moreover, there is no significant advantage to splitting fertilizer application over time during the growing season. An analysis of government data indicates that, over the past 40 years, Utah has become a net importer of apples (1997), peaches (1987), and sweet cherries (2005), indicating increased local market opportunities. Increasing the fruit supply to the local market can best be accomplished by increasing yields and fruit quality on existing orchard acreage. Optimizing annual P and K nutrient management is an important key to maximizing yield and fruit quality. The results provide foundational guidelines of nutrient management for optimizing tart cherry production and fruit quality under regionally specific conditions.

En este trabajo hemos abordado el estudio de la respuesta a estrés alcalino de S. cerevisiae utilizando como herramientas principales dos técnicas de análisis a gran escala. Por un lado, hemos realizado un análisis mediante microarrays de DNA de la respuesta transcripcional a estrés alcalino y, por otro, hemos utilizado una biblioteca de más de 4800 mutantes para identificar genes esenciales para la supervivencia a pH alcalino. Todo ello nos ha permitido identificar nuevos aspectos en la respuesta y en la adaptación de dicha levadura a estrés alcalino. En primer lugar, partiendo de la identificación de ENA1 y PHO89 como genes regulados por pH alcalino cuya expresión es dependiente de calcineurina hemos establecido una relación entre la respuesta a pH alcalino y la vía de señalización de calcio/calcineurina. Demostramos que la alcalinización extracelular estimula el transporte de calcio desde el exterior dando lugar a un incremento en los niveles citoplasmáticos de este catión. Esta señal es la que desencadena la activación de la fosfatasa calcineurina, cuya acción principal, aunque no la única, es activar la expresión de una serie de genes implicados en la resistencia a pH alcalino. Por otro lado, los resultados de microarrays indican que el estrés alcalino induce la transcripción de varios de los genes implicados en la obtención de fosfato y en el metabolismo de hierro y cobre. A su vez, el análisis de mutantes revela que tanto la integridad de elementos del regulón PHO como la del transporte de metales es esencial para la supervivencia en medio alcalino. Todo ello sugiere que la alcalinización medioambiental genera una situación de escasez de estos iones.Asimismo hemos demostrado que la alcalinización extracelular provoca un incremento intracelular de ROS (o especies reactivas de oxígeno), lo que genera una situación de estrés oxidativo capaz de activar un conjunto de genes a través de los mecanismos específicos de respuesta a estrés oxidativo. Por último, hemos descubierto una implicación de la vía de la integridad de la pared celular (CWI) en la respuesta a estrés alcalino. Hemos descrito que la ausencia de varios elementos implicados en dicha vía, como el sensor Wsc1 o las quinasas Bck1 y Slt2, da lugar a un fenotipo de sensibilidad a pH alcalino. Además, confirmamos que este estrés provoca la activación de Slt2, la MAPK de la vía CWI, y que el sensor de la vía más relevante en dicha activación es Wsc1. Por otro lado, el estudio de la respuesta transcripcional a pH alcalino de un mutante slt2 sugiere que esta quinasa es responsable de una parte de la respuesta transcripcional y que, probablemente, la alcalinización extracelular tiene efectos sobre la estructura de glucanos de la pared celular.La conclusión final que se extrae de todos nuestros resultados es que la alcalinización medioambiental da lugar a una respuesta adaptativa que no es el resultado de la activación de una única vía de señalización específica para pH alcalino, sino que es el producto de activar diversas vías encaminadas a paliar las variadas alteraciones producidas por el estrés alcalino. / In this work we have studied the response to alkaline stress in the yeast Saccharomyces cerevisiae. To this end we have used mainly two high throughput analysis tools. First, we have performed an exhaustive analysis of the transcriptional response of this yeast to this kind of stress. In addition, we have used a mutant library, composed of more than 4800 mutants, in order to identify genes whose lack cause a growth defect in alkaline conditions. First we have identified ENA1 and PHO89 as two genes overexpressed under alkaline conditions whose response to this stress was partially or totally dependent, respectively, on the phosphatase calcineurin. This represents the first evidence about the existence of a relationship between the alkaline response and the calcium/calcineurin signaling pathway. Further analyses have also demonstrated that extracellular alkalinization stimulates the import of calcium from the medium provoking a rise in the intracellular levels of this cation. This increment of calcium activates the calcineurin which functions, at least in part, promoting the expression of a set of genes involved in the tolerance to alkali.In addition, the microarray data has shown that the alkaline stress induces the transcription of some of the genes involved in the phosphate uptake and in iron and copper metabolism. Besides, mutant analysis has revealed that the integrity of elements of the regulon PHO and that proper system to transport the mentioned metals are essential for the survival under alkaline conditions. Taken together, these evidences suggest that alkalinization of the environment leads to a situation of starvation of these anions.We also have demonstrated that alkaline pH increments intracellular ROS (reactive oxygen species) that, in turn, cause an oxidative stress situation that activates the transcription of a subset of genes involved in the defense to oxidation.Finally, we have reported a relationship between the cell wall integrity (CWI) pathway and the alkaline response. Cells lacking some proteins previously related to this pathway, such as the Wsc1 sensor or the Bck1 and the Slt2 kinases, are hypersensitive to alkaline stress. We also have confirm that alkaline stress causes the activation of Slt2, the MAPK of the CWI pathway, and that Wsc1 is the major sensor involved in this activation. In addition, a study of the transcriptional response to alkali in a slt2 mutant has shown that this kinase is involved in the global transcriptional response to alkaline stress.The final conclusion that can be extracted from all the data presented here is that the alkalinization of the ambient triggers an adaptive response that results from the activation of multiple cellular pathways.

La respuesta de adaptación de la levadura Saccharomyces cerevisiae a la alcalinización ambiental provoca una remodelación de su expresión génica. Una diana clave es el gen ENA1 que codifica una ATPasa de sodio, y cuya inducción por pH alcalino está mediada por las vías de calcineurina y el Rim101.En un estudio previo se identificaron dos regiones del promotor de ENA1 responsables de su respuesta al álcali, la ARR1 (Alkaline Responsive Region 1) que es calcineurina-dependiente y ARR2 que es calcineurina-independiente. En este trabajo restringimos la región responsable de la respuesta alcalina de ARR2 a un pequeño fragmento de 42 nucleótidos que denominamos MCIR (por Minimum Calcineurin Independent Response). MCIR contiene un elemento MIG, capaz de unir a los represores Mig1 y Mig2. Observamos que la respuesta a pH alcalino de la MCIR se anula en células que carecen de Snf1, la quinasa que regula la actividad represora de Mig1 en función de la disponibilidad de glucosa. En cambio, su respuesta se ve moderadamente reducida en cepas rim101, mientras que el doble mutante mig1 mig2 presenta altos niveles de expresión a pH alcalino. Además, la deleción de NRG1 resulta en una expresión elevada y la inducción de MCIR es marginal en el cuádruple mutante nrg1,2 mig1,2. También demostramos que Nrg1 se une al extremo 5' de la ARR2 in vitro e in vivo. Por lo tanto, la respuesta de ENA1 que es calcineurina independiente esta regulada por Rim101 (a través de Nrg1) y por Snf1 (a través de Nrg1 y Mig2). De esta manera, la inducción del promotor de ENA1 por pH alcalino en un mutante rim101snf1 en presencia del inhibidor químico de la calcineurina FK506 se anula totalmente. Por lo tanto, la respuesta transcripcional de ENA1 a estrés alcalino, integra tres vías de señalización, cuya importancia relativa es Snf1 > calcineurina > Rim101.La CK2 es una quinasa que está conservada en eucariotas y participa en diversos procesos celulares. En S. cerevisiae cepas que carecen de las subunidades reguladoras Ckb1 y/o Ckb2 de la CK2 son muy sensibles a cationes de litio y de sodio. En este estudio confirmamos observaciones anteriores que describían que la respuesta de ENA1 a estrés salino y alcalino está disminuida en células que carecen de Ckb1 y/o Ckb2. Además demostramos que los mutantes ckb son sensibles a pH alcalino. Las tres vías de señalización (Rim101, calcineurina, Snf1) responsables de la regulación de ENA1 en condiciones de estrés alcalino se examinaron para posibles interacciones con la CK2. Nuestros resultados sugieren que CK2 y calcineurina regulan la expresión de ENA1 de manera independiente. Además, mostramos que la deleción de RIM101 resulta en inducción de la expresión de ENA1, disminuida en condiciones de estrés salino, y que la deleción simultanea de CKB agrava solo ligeramente el defecto de las cepas rim101 en la expresión salina y alcalina de ENA1. Deleción del factor de transcripción Nrg1 en un fondo genético ckb resulta en niveles de expresión de ENA1 relativamente altos en condiciones de estrés salino y alcalino. Estos resultados, junto con datos anteriores que muestran que Nrg1 se fosforila por CK2 en estas condiciones de estrés, son compatibles con una supuesta interacción entre CK2 y la vía Rim101. Cabe destacar que la deleción de CKB repara el defecto que presentan las células snf1 en la expresión de ENA1 bajo estrés salino y alcalino y que los mutantes ckb1,2 snf1 presentan un crecimiento en litio mayor que la cepa salvaje, sugiriendo la existencia de una interacción compleja entre CK2 y Snf1. / The adaptive response of the yeast Saccharomyces cerevisiae to environmental alkalinization results in remodeling of gene expression. A key target is the gene ENA1, encoding a sodium ATPase, whose induction by alkaline pH was shown to integrate at least two different signals, mediated by the calcineurin and the Rim101 pathways.Early work in our laboratory identified two regions in the ENA1 promoter required for full response to alkalinization, the ARR1 (from Alkaline Responsive Region 1), whose response is calcineurin-dependent and ARR2, whose response is calcineurin-independent. In this work we have restricted the alkaline response of ARR2 to a smaller fragment of 42 nucleotides that we denominated MCIR (from Minimum Calcineurin Independent Response). MCIR contains a MIG element, able to bind Mig1 and Mig2 repressors. We observe that high pH-induced response driven from MCIR is largely abolished in cells lacking Snf1, the protein kinase that regulates repressor activity of Mig1 with respect to glucose availability, and results moderately reduced in a rim101 strain, whereas the double mig1 mig2 mutant presents high levels of expression upon alkaline stress. In addition, deletion of NRG1 results in increased expression and induction from the MCIR region is marginal in a quadruple nrg1,2 mig1,2 mutant. We also demonstrate that Nrg1 binds to the 5´-end of the ARR2 region in vitro and in vivo. Therefore, the calcineurin-independent response of the ENA1 gene is under the regulation of Rim101 (through Nrg1) and Snf1 (through Nrg1 and Mig2). Accordingly, induction by alkaline stress of the entire ENA1 promoter in a snf1 rim101 mutant in the presence of the calcineurin inhibitor FK506 is completely abolished. Thus, the transcriptional response to alkaline stress of the ENA1 gene integrates three different signaling pathways, whose relative potency is Snf1 > calcineurin > Rim101. CK2 is a well conserved kinase among eukaryotes that participates in many different cellular processes. In Saccharomyces cerevisiae, strains lacking the regulatory subunits Ckb1 and/or Ckb2 of this kinase are hypersensitive to sodium and lithium cations. However, the mechanism by which CK2 affects yeast salt tolerance is not known. In this study we confirm previous observations that the alkaline and saline response of ENA1 is decreased in strains lacking Ckb1 and/or Ckb2. Furthermore, we show that ckb mutants are sensible at alkaline pH. The three pathways (Rim101, calcineurin and Snf1) responsible for ENA1 regulation under alkaline stress conditions were examined for any possible interaction with CK2. Our results suggest that CK2 and calcineurin regulate ENA1 expression under alkaline and lithium stress in an independent fashion. Moreover, we show that deletion of RIM101 results in decreased ENA1 induction under lithium stress conditions and that simultaneous mutation of CKB only slightly aggravates the defect that presents the rim101 strain in ENA1 alkaline and saline expression. Mutation of the Nrg1 transcription factor in a ckb background leads to relatively high levels of ENA1 expression under alkaline and lithium stress conditions. These results, together with previous data showing that Nrg1 is phosphorylated by CK2 under these stress conditions, support a possible interaction between the CK2 and the Rim101 pathways. Remarkably, deletion of CKB partially counteracts the defect that snf1 mutants present in ENA1 saline and alkaline expression, and ckb1,2 snf1 mutants are as tolerant as wild type cells to lithium ions, revealing a complex interaction between CK2 and Snf1.

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An experimental study was conducted to verify experimentally whether sand consolidation by high-temperature alkaline treatment was possible in the heavy oil Bachaquero-01 reservoir. The experiments were conducted using sand samples from a core taken from well LL-231 from Bachaquero-01 reservoir. The sample was placed in a vertical 18 in. long aluminum cylindrical cell with an ID of 1.5 in. The top half of the cell was thermally insulated and the bottom half was cooled. The alkaline treatment (pH 11 -12) at 230ºC - 250ºC and 900 – 1000 psig was injected at 20 ml/min for 3 to 6 hours at the top of the cell and liquid produced at the bottom of the cell. After each experiment, the cell contents were removed and analyzed to determine if consolidation occurred. An electron microprobe was used to analyze both loose and polished epoxy-mounted sand grains to determine any change in texture and composition of the sand pack and precipitation and growth of secondary phases. Results showed that under the experimental conditions reached in the laboratory; the consolidation of Bachaquero-01 sand did not occur. However some secondary materials were produced in the runs where sand samples were cleaned of oil. It was noticed that the amount of these secondary phases was not sufficient to bridge the sand grains. These results indicate that further research is needed to better understand and optimize the parameters affecting the consolidation of Bachaquero-01 sands.