In the course of our efforts to resolve Pi transport mechanisms in the model fungus Neurospora crassa we identified a null mutant, par-1, that displays enhanced Pi transport activity specifically under alkaline growth conditions. The PAR-1 protein is related to PalF of Aspergillus nidulans, which is one component of an ambient pH signaling pathway that is conserved among fungi. A deletion mutant for the PacC homolog, another component of the same pathway, phenocopies par-1, demonstrating that a defect in pH signaling is responsible for the altered Pi transport activity. Our results indicate that pH signaling in N. crassa plays an important role in coordinating high and low affinity Pi transport in response to ambient pH, but through different mechanisms. Sulfate acquisition also is influenced by pH signaling, suggesting that this regulatory system has a broad role in nutrient uptake and homeostasis.

The research of pH chantes in ripe smoke-dried sausvages during the whole technological process of production. The research is made at ŽŪB „Nematekas“ (agricultural company). The smoke-dried sausages were chosen as subject of research. One group of products was ripened for 7 days, the other one – for 13 days. The raw materials used for the production of all sausages were the same as follows: beef ham (I sort), beef (II sort), pork, pork or beef lard. The dynamics of pH and weight changes was researched. Following results were fixed: The biggest waste of weight – 25 % in 12 days were achieved by “Nerija”, “Karkle”, “Husarai” and “Airiska” sausages. The weight most dropped of in smoke-dried sausage “Nerija”, even 193 g and least in sausage “Kaimiska”, only 131 g. Remained part of smoke-dried products weight were various in scale from 190 to 155 g. The biggest alterations of smoke-dried sausages have happened in period of 2 days ripening. During that period most of production pH has reduced up to demanded 5,3 pH level. The biggest pH reduction were noticed in smoke-dried sausage “Airiska” – from 5,97 to 5,22, the smallest pH reduction were noticed in “Zemaitiskas Skilandis” – from 5,78 to 5,34. Remained specimens pH variations were from 5,42 to 5,29. Most significant pH alterations, noticed during first 2 days, were result of time, required for adaptation, for new microorganisms adaptation in new environment. In period of 5 -8 days because of reduced humidity microorganisms... [to full text]

Supplies of nonrenewable fossil fuels are becoming more limited even as they continue to contribute to pollution and economic concerns. Alternative sources of energy must be developed that help minimize these problems. One potential source of energy is the production of biofuels from algae. Here we evaluate algae found in South Texas brackish water ponds used for aquaculture of fish as a possible source of biofuels. In particular, we examine the effects of salinity and pH on the growth and lipid content of the algae. Samples of algae from the ponds exhibited high levels of growth and lipid production at a salinity of 9 ppt and pH 7. These conditions are similar to the natural conditions of the ponds, indicating that they may be a good source of algal biofuels. / text

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La producción de truchas se viene desarrollando de manera artesanal, y generalizada en todo el país; este tipo de crianza se realiza en la gran mayoría de casos con asistencia de ONG’s que brindan apoyo técnico a los campesinos que ven como alternativa económica la crianza de esta especie. Sin embargo, la crianza de truchas en nuestro país no cuenta con herramientas tecnológicas que faciliten una adecuado monitoreo y medición de parámetros de agua a bajo costo, de manera que durante la etapa de producción y comercialización los lleva a tener pérdidas significativas, además de no ofrecer la calidad necesaria de agua en los estanques de crianza para mejorar el desarrollo de los peces. Dada la problemática, indisponible el uso de una alternativa tecnológica económica y eficiente a fin de mantener la crianza de truchas sostenible y de gran calidad. En la tesis está previsto el desarrollo de un instrumento de medida con resolución de 2 centésimas y contribuir a mantener los niveles óptimos de acidez y alcalinidad en todas las etapas de crianza de truchas. Cuenta con una pantalla donde se visualiza la medida del pH y el rango establecido por el usuario y muestra el error asociado a este. Puede ser calibrado para garantizar que la medida sea la correcta mediante soluciones buffer de pH. Además tiene la posibilidad de poder enviar los datos medidos de pH vía el puerto serial incorporado en el equipo para que puedan ser visualizados en la pantalla de una computadora personal y analizar los datos. El cuerpo del presente documento consta de cuatro capítulos. El primero presenta la problemática a todo nivel y el análisis de la misma llegando finalmente a la síntesis de la problemática donde se puntualizan los problemas. El segundo capítulo muestra los avances tecnológicos en cuanto al desarrollo y métodos de medición de pH. En el tercer capítulo se plantea la hipótesis y se definen objetivos y limites, además se propone la metodología y se presentan las etapas que seguirán en desarrollo del proyecto. El último capítulo contiene todo el desarrollo y la ingeniería del proyecto en sí, los detalles del diseño electrónico y de programación utilizada en los dispositivos. En cuento a los resultado de mayor importancia y relevancia, en el ámbito de la ciencia, se demuestra la factibilidad de medir el pH del agua; así mismo en materia de desarrollo, la versatilidad y bajo costo para la construcción del equipo de medición. / Tesis

Lysosomes are intracellular organelles that were considered for a long time to be simply an acidic and hydrolytically active end point of trafficking routes for degradation, in the last 20 years, light has been shed on their functional heterogeneity and striking role in signalling and nutrient homeostasis. While the dynamic nature and variety of lysosomal functions are now better appreciated, the mechanisms governing lysosomal fusion, reformation, signalling, and homeostasis remain to be fully elucidated, and are investigated here. In this study, endolysosomes which formed by fusion of late endosomes with lysosomes and are thought to be the predominant site of hydrolytic activity, were further characterised. Using live cell imaging and fluorescent labelling, the proportion of endolysosomes in the total pool of lysosomes was estimated using probes to their acidity and cathepsin activity, and their larger size compared to storage lysosomes was observed. The endolysosomal membrane was also shown to be marked by Rab7, Rab9, PI(3,5)P2 supporting the role of endolysosomes a highly active and dynamic principal site of hydrolase activity. The contributions of VAMP7 and VAMP8 to endolysosome fusion, measured by delivery of endocytosed cargo from late endosomes to endolysosomes, were analysed by CRISPR-Cas9 mediated knockout. Cells lacking VAMP7 and VAMP8 had no effect on delivery to endolysosomes, however at EM level, they displayed extensive tethering between late endocytic organelles, and accumulated small tethered vesicles. YKT6 knockdown impeded delivery to endolysosomes in VAMP7+VAMP8 knockout cells, which was rescued by VAMP7 expression, suggesting YKT6 substituted for VAMP7 in lysosome fusion. Following the hypothesis that reversible dissociation of V1 and Vo sectors of the V- ATPase may control the increase in pH of reforming storage lysosomes, cells expressing tagged V1G1 and Voa3 were generated. These markers of both sectors are present on endolysosomal membranes, and on the emerging endolysosomal tubules, suggesting the V1 and Vo sectors remain associated at this earliest stage of lysosome reformation, but these markers are still in development. IV Two assays were developed to give a readout of, and assess lysosomal stress. Firstly, an assay measuring TFEB-GFP translocation to the nucleus gave a robust and quantifiable readout of lysosomal perturbation. Secondly, a qPCR assay was developed to measure lysosomal gene upregulation as a downstream reporter of TFEB-activating lysosomal perturbations, however this assay, despite being more lysosome-specific, lacked the consistency and dynamic range of the TFEB translocation quantification. In summary, lysosomes are a heterogeneous collection of organelles, which have been better characterised primarily according to their acidity and hydrolytic capacity. Additionally, more SNAREs appear to be involved in lysosome fusion in cells than suggested by cell free assays, and I have developed tools to trace the V-ATPase during reformation of lysosomes after fusion to form endolysosomes. Lastly, I have developed a robust, reporter for a range of lysosomal stress-inducing conditions, providing a broad indication of their effects on lysosomal signalling and homeostasis.

Triflxysulfuron is a sulfonylurea herbicide developed for postemergence weed control in cotton, sugarcane, and turf. Greenhouse and laboratory studies were conducted at the Texas A&M University campus and at the USDA-ARS research facility in Stoneville, MS to: 1) quantify the dissipation of trifloxysulfuron in a spray tank at 0, 1, 3, 7, 14, and 21 d after mixing as influenced by pH of the spray carrier and evaluate the resulting effects on efficacy on Palmer amaranth (Amaranthus palmeri S. Wats); 2) determine the effect of spray carrier pH on absorption and translocation of radiolabeled trifloxysulfuron in Palmer amaranth and Texasweed (Caperonia palustris (L.) St. Hil.); 3) determine average edge-of-field concentrations, total mass losses, and fractional losses of trifloxysulfuron applied to cotton at the 5-leaf stage and to bare soil as influenced by simulated rainfall. The dissipation of trifloxysulfuron followed first-order kinetics. Calculated half-life values indicated that hydrolysis occurred more rapidly with the more acidic spray carriers with little or no difference between neutral and alkaline pH levels. Bioassay on Palmer amaranth showed no differences in plant dry weights due to pH level or dissipation time. The absorption of 14C-trifloxysulfuron was greater for Palmer amaranth than for Texasweed when averaged over time and pH. Altering pH did not affect the translocation of trifloxysulfuron in Palmer amaranth. In contrast, translocation of 14C-trifloxysulfuron in Texasweed increased in the order of pH 5 < pH 7 = pH 9. Cumulative trifloxysulfuron losses in runoff from cotton plots were 0.21 g ha-1 while losses from bare plots were 0.13 g ha-1. These values corresponded to fractional losses of 2.7% for cotton plots and 1.7% for bare plots of the total amount applied. These studies provide important information regarding the stability, plant uptake, and runoff potential of a commonly used sulfonylurea herbicide.

Triflxysulfuron is a sulfonylurea herbicide developed for postemergence weed control in cotton, sugarcane, and turf. Greenhouse and laboratory studies were conducted at the Texas A&M University campus and at the USDA-ARS research facility in Stoneville, MS to: 1) quantify the dissipation of trifloxysulfuron in a spray tank at 0, 1, 3, 7, 14, and 21 d after mixing as influenced by pH of the spray carrier and evaluate the resulting effects on efficacy on Palmer amaranth (Amaranthus palmeri S. Wats); 2) determine the effect of spray carrier pH on absorption and translocation of radiolabeled trifloxysulfuron in Palmer amaranth and Texasweed (Caperonia palustris (L.) St. Hil.); 3) determine average edge-of-field concentrations, total mass losses, and fractional losses of trifloxysulfuron applied to cotton at the 5-leaf stage and to bare soil as influenced by simulated rainfall. The dissipation of trifloxysulfuron followed first-order kinetics. Calculated half-life values indicated that hydrolysis occurred more rapidly with the more acidic spray carriers with little or no difference between neutral and alkaline pH levels. Bioassay on Palmer amaranth showed no differences in plant dry weights due to pH level or dissipation time. The absorption of 14C-trifloxysulfuron was greater for Palmer amaranth than for Texasweed when averaged over time and pH. Altering pH did not affect the translocation of trifloxysulfuron in Palmer amaranth. In contrast, translocation of 14C-trifloxysulfuron in Texasweed increased in the order of pH 5 < pH 7 = pH 9. Cumulative trifloxysulfuron losses in runoff from cotton plots were 0.21 g ha-1 while losses from bare plots were 0.13 g ha-1. These values corresponded to fractional losses of 2.7% for cotton plots and 1.7% for bare plots of the total amount applied. These studies provide important information regarding the stability, plant uptake, and runoff potential of a commonly used sulfonylurea herbicide.

Two Texas fed beef and cow/bull packing plants were surveyed for high pH beef carcasses as well as the evaluation of functional properties of high pH beef in whole muscle beef jerky, frankfurters, and snack stick production. An estimated 42% of cow carcasses were of 6.0 muscle pH or greater as well as exhibiting darker, less red colored lean. Jerky high in pH from cow inside rounds resulted in the greatest percent moisture and least percent protein compared to other treatments. High pH cooked jerky were higher in (P < 0.05) pH and water activity and lower in percent fat and shear force values. In cooked jerky slices, fed-high resulted in the highest percent MPR and cook yield, but was the most tender. In contrast, fed-normal resulted in the least water activity, MPR and toughest jerky slices. In frankfurter production, emulsion stability and hydration values was highest for C (1.98mL) followed by 100H (3.37mL) that decreased as percent high pH decreased. As storage day increased, frankfurter pH decreased, especially by day 56 (5.67) where LAB and APC counts had reached a log of 6.0 indicative of spoilage by day 28 and became lighter and less red in color with minimal lipid oxidation. 100H was harder and less cohesive with trained panelists reported containing at least 50% high pH meat was harder. The pH and internal color of cooked snack sticks significantly increased and became lighter and redder as percent high pH meat increased. Even though water activity compared to a whole muscle dry product or an emulsified, water added product ranged from 0.85 to 0.86 (P > 0.05), minimal (P greater than 0.05) lipid oxidation occurred. 100N resulted in the least percentage of fat but 3% more (P less than 0.05) protein and highest shear force values. Overall, beef raw materials high in pH may be better suited in a semi-dry fermented product.

Reproduction de : Thèse de doctorat : Génie des procédés et de l'environnement : Toulouse, INPT : 2008. / Titre provenant de l'écran-titre. Bibliogr. 103 réf.