902 resultados para acid and alkali-tolerant


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Plant growth regulators and biostimulants have been used as an agronomic technique to optimize the production of seedlings in various crops. This study aimed to evaluate the influence of gibberellic acid and the biostimulant Stimulate® on the initial growth of tamarind (Tamarindus indica L.). The experiments were conducted in a nursery with 50% shading, in a randomized block design with five replications and five plants per plot. Thirty eight days after sowing, the leaves were sprayed seven times a day with 0.0 (control), 0.8, 1.6, 2.4 and 3.2 mL of gibberellic acid L-1 aqueous solution and with 0.0 (control), 6.0,12.0, 18.0, and 24.0 mL Stimulate® L-1 aqueous solution. Stem diameter (SD), plant height (PH), longest root length (LRL), shoot dry mass (SDM), root dry mass (RDM) and RDM:SDM ratio were evaluated ninety days after sowing. Variance and regression analysis showed that GA3 at 4% promoted plant growth (height), but had no significant effect on stem diameter, longest root length, shoot and root dry mass and the RDM:SDM ratio. On the other hand, all concentrations of Stimulate® significantly increased plant height and shoot and root dry mass of tamarind seedlings.

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All plants are typically confronted to simultaneous biotic and abiotic stress throughout their life cycle. Low inorganic phosphate (Pi) is the most common nutrient deficiency limiting plant growth in natural and agricultural ecosystems while insect herbivory accounts for major losses in plant productivity and impacts on ecological and evolutionary changes in plant populations. Here we report that plants experiencing Pi deficiency induce the jasmonic acid (JA) pathway and enhance their defence against insect herbivory. The phol mutant is impaired in the translocation of Pi from roots to shoots and shows the typical symptoms associated with Pi deficiency, including high anthocyanin and poor shoot growth. These phol shoot phenotypes were significantly attenuated by blocking the JA biosynthesis or signalling pathways. Wounded phol leaves hyper-accumulated JA in comparison to wild type, leading to increased resistance against the generalist herbivore Spodoptera littoralis. Pi deficiency also triggered enhanced resistance to herbivory in wild-type Arabidopsis as well as tomato and tobacco, revealing that the link between Pi deficiency and JA-mediated herbivory resistance is conserved in a diversity of plants, including crops. We performed a phol suppressor screen to identify new components involved in the adaptation of plants to Pi deficiency. We report that the THO RNA TRANSCRIPTION AND EXPORT (THO/TREX) complex is a crucial component involved in modulating the Pi- deficiency response. Knockout mutants of at least three members of the THO/TREX complex, including TEX1, HPR1, and TH06, can suppress the phol shoot phenotype. Grafting experiments showed that loss of function of TEX1 only in the root was sufficient to suppress the reduced shoot growth phenotype of phol while maintaining low Pi contents. This indicates that TEX1 is involved in a long distance root-to-shoot signalling component of the Pi-deficiency response. We identified a small MYB-like transcription factor, RAD LIKE 3 (RL3), as a potential downstream target of the THO/TREX complex. RL3 expression is induced in phol mutants but attenuated in phol-7 texl-4 double mutants. Identical to knockout mutants of the THO/TREX complex, rl3 mutants can suppress the phol shoot phenotypes. Interestingly, RL3 is induced during Pi deficiency and is described in the literature as likely being mobile. It is therefore a promising new candidate involved in the root-to-shoot Pi-deficiency signalling response. Finally, we report that PHOl and its homologue PH01:H3 are involved in the co-regulation of Pi and zinc (Zn) homeostasis. PH01;H3 is up-regulated in response to Zn deficiency and, like PHOl, is expressed in the root vascular cylinder and localizes to the Golgi when expressed transiently in tobacco cells. The phol;h3 mutant accumulates more Pi as compared to wild-type when grown in Zn-deficient medium, but this increase is abolished in the phol phol;h3 double mutant. These results suggest that PH01;H3 restricts the PHOl-mediated root-to-shoot Pi transfer in responsé to Zn deficiency. Résumé Au cours de leur cycle de vie, toutes les plantes sont généralement confrontées à divers stress biotiques et abiotiques. La carence nutritionnelle la plus fréquente, limitant la croissance des plantes dans les écosystèmes naturels et agricoles, est la faible teneur en phosphate inorganique (Pi). Au niveau des stress biotiques, les insectes herbivores sont responsables de pertes majeures de rendement et ont un impact considérable sur les changements écologiques et évolutifs dans les populations des plantes. Au cours de ce travail, nous avons mis en évidence que les plantes en situation de carence en Pi induisent la voie de l'acide jasmonique (JA) et augmentent leur défense contre les insectes herbivores. Le mutant phol est déficient dans le transport du phosphate des racines aux feuilles et démontre les symptômes typiques associés à la carence, tels que la forte concentration en anthocyane et une faible croissance foliaire. Ces phénotypes du mutant phol sont significativement atténués lors d'un blocage de la voie de la biosynthèse ou des voies de signalisation du JA. La blessure des feuilles induit une hyper-accumulation de JA chez phol, résultant en une augmentation de la résistance contre l'herbivore généraliste Spodoptera littoralis. Outre Arabidopsis, la carence en Pi induit une résistance accrue aux insectes herbivores aussi chez la tomate et le tabac. Cette découverte révèle que le lien entre la carence en Pi et la résistance aux insectes herbivores via le JA est conservé dans différentes espèces végétales, y compris les plantes de grandes cultures. Nous avons effectué un crible du suppresseur de phol afin d'identifier de nouveaux acteurs impliqués dans l'adaptation de la plante à la carence en Pi. Nous rapportons que le complexe nommé THO RNA TRANSCRIPTION AND EXPORT (THO/TREX) est un élément crucial participant à la réponse des feuilles à la carence en Pi. Les mutations d'au moins trois des membres que composent le complexe THO/TREX, incluant TEX1, HPR1 et 77/06, peuvent supprimer le phénotype de phol. Des expériences de greffes ont montré que la perte de fonction de TEX1, seulement dans la racine, est suffisante pour supprimer le phénotype de la croissance réduite des parties aériennes observé chez le mutant phol, tout en maintenant de faibles teneurs en Pi foliaire. Ceci indique que TEX1 est impliqué dans la signalisation longue distance entre les racines et les parties aériennes. Nous avons identifié un petit facteur de transcription proche de la famille des MYB, RAD LIKE 3 (RL3), comme une cible potentielle en aval du complexe THO / TREX. L'expression du gène RL3 est induite dans le mutant phol mais atténuée dans le double mutant phol-7 texl-4. Exactement comme les plantes mutées d'un des membres du complexe THO/TREX, le mutant rl3 peut supprimer le phénotype foliaire de phol. RL3 est induit au cours d'une carence en Pi et est décrit dans la littérature comme étant potentiellement mobile. Par conséquent, il serait un nouveau candidat potentiellement impliqué dans la réponse longue distance entre les racines et les parties aériennes lors d'un déficit en Pi. Enfin, nous reportons que PHOl et son homologue PHOl: H3 sont impliqués dans la co- régulation de l'homéostasie du Pi et du zinc (Zn). PHOl; H3 est sur-exprimé en réponse au déficit en Zn et, comme PHOl, est exprimé dans les tissus vasculaires des racines et se localise dans l'appareil de Golgi lorsqu'il est exprimé de manière transitoire dans des cellules de tabac. Le mutant phol; h3 accumule plus de Pi par rapport aux plantes sauvages lorsqu'il est cultivé sur un milieu déficient en Zn, mais cette augmentation en Pi est abolie dans le double mutant phol phol; h3. Ces résultats suggèrent qu'en réponse à une carence en Zn, PHOl; H3 limite l'action de PHOl et diminue le transfert du Pi des racines aux parties aériennes.

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In esterification of oleic acid with methanol at 25 °C HPA displayed the highest activity. Moreover the HPA could be reused after being transformed into its cesium salt. In the reaction of etherification of glycerol HPA and Amberlyst 35W showed similar initial activity levels. The results of acid properties demonstrate that HPA is a strong protonic acid and that both surface and bulk protons contribute to the acidity. Because of its strong affinity for polar compounds, HPA is also seemingly dissolved in both oleic acid and methanol. The reaction in this case proceeds with the catalyst in the homogenous phase.

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In this work, a spectrophotometric methodology was applied in order to determine epinephrine (EP), uric acid (UA), and acetaminophen (AC) in pharmaceutical formulations and spiked human serum, plasma, and urine by using a multivariate approach. Multivariate calibration methods such as partial least squares (PLS) methods and its derivates were used to obtain a model for simultaneous determination of EP, UA and AC with good figures of merit and mixture design was in the range of 1.8 - 35.3, 1.7 - 16.8, and 1.5 - 12.1 µg mL-1. The 2nd derivate PLS showed recoveries of 95.3 - 103.3, 93.3 - 104.0, and 94.0 - 105.5 µg mL-1 for EP, UA, and AC, respectively.

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The synthesis of sodium 2-chlorobenzylidenepyruvate and its corresponding acid as well as binary, binary together with it's acid or hydroxo-2-chorobenzylidenepyruvate of aluminium (III), gallium (III) and indium (III), were isolated. Chemical analysis, thermogravimetry, derivative thermogravimetry (TG/DTG), simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and X-ray powder diffractometry have been employed to characterize and to study the thermal behaviour of these compounds. The results provided information concerning the stoichiometry, crystallinity, thermal stability and thermal decomposition.

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An evaluation of hydration and thermal decomposition of HAlg and its sodium salt is described using thermogravimetry (TG) and differential scanning calorimetry (DSC). TG curves in N2 and air, were obtained for alginic acid showed two decomposition steps attributed to loss of water and polymer decomposition respectively. The sodium alginate decomposed in three steps. The first attributed to water loss, followed by the formation of a carbonaceous residue and finally the Na2CO3. DSC curves presented peaks in agreement with the TG data. In the IR alginic acid presented bands at 1730 and 1631 cm-1, while sodium alginate presented a doublet at 1614 e 1431 cm-1, evidencing the presence of salified carboxyl groups.

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E-Lychnophoric acid 1, its derivative ester 2 and alcohol 3 killed 100% of trypomastigote blood forms of Trypanosoma cruzi at the concentrations of 13.86, 5.68, and 6.48 µg/mL, respectively. Conformational distribution calculations (AM1) of 1, 2 and 3 gave minimum energies for the conformers a, b, c, and d, which differ from each other only in the cyclononene ring geometry. Calculations (DFT/BLYP/6-31G*) of geometry optimization and chemical properties were performed for conformers of 1, 2, and 3. The theoretical results were numerically compared to the trypanocidal activity. Calculated values of atomic charge, orbital population, and vibrational frequencies showed that the C-4-C-5 pi-endocyclic bond does not affect the trypanocidal activity of the studied compounds. Nevertheless, the structure of the group at C-4 strongly influences the activity. However, the theoretical results indicated that the intra-ring (C-1 and C-9) and pi-exocycle (C-8 and C-14) carbons of caryophyllene-type structures promote the trypanocidal activity of these compounds.

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Papperstillverkningen störs ofta av oönskade föreningar som kan bilda avsättningar på processytor, vilket i sin tur kan ge upphov till störningar i pappersproduktionen samt försämring av papperskvaliteten. Förutom avsättningar av vedharts är stenliknande avlagringar av svårlösliga salter vanliga. I vårt dagliga liv är kalkavlagringar i kaffe- och vattenkokare exempel på liknande problem. I massa- och pappersindustrin är en av de mest problematiska föreningarna kalciumoxalat; detta salt är nästan olösligt i vatten och avlagringarna är mycket svåra att avlägsna. Kalciumoxalat är också känt som en av orsakerna till njurstenar hos människor. Veden och speciellt barken innehåller alltid en viss mängd oxalat men en större källa är oxalsyra som bildas när massan bleks med oxiderande kemikalier, t.ex. väteperoxid. Kalciumoxalat bildas när oxalsyran reagerar med kalcium som kommer in i processen med råvattnet, veden eller olika tillsatsmedel. I denna avhandling undersöktes faktorer som påverkar bildningen av oxalsyra och utfällningen av kalciumoxalat, med hjälp av bleknings- och utfällningsexperiment. Forskningens fokus låg speciellt på olika sätt att förebygga uppkomsten av avlagringar vid tillverkning av trähaltigt papper. Resultaten i denna avhandling visar att bildningen av oxalsyra samt utfällning av kalciumoxalat kan påverkas genom processtekniska och våtändskemiska metoder. Noggrann avbarkning av veden, kontrollerade förhållanden under den alkaliska peroxidblekningen, noggrann hantering och kontroll av andra lösta och kolloidala substanser, samt utnyttjande av skräddarsydd kemi för kontroll av avlagringar är nyckelfaktorer. Resultaten kan utnyttjas då man planerar blekningssekvenser för olika massor samt för att lösa problem orsakade av kalciumoxalat. Forskningsmetoderna som användes i utfällningsstudierna samt för utvärdering av tillsatsmedel kan också utnyttjas inom andra områden, t.ex. bryggeri- och sockerindustrin, där kalciumoxalatproblem är vanligt förekommande. -------------------------------------------- Paperinvalmistusta häiritsevät usein erilaiset epäpuhtaudet, jotka kiinnittyvät prosessipinnoille ja haittaavat tuotantoa sekä paperin laatua. Puun pihkan lisäksi eräs yleinen ongelma on niukkaliukoisten suolojen aiheuttamat kivettymät. Kalkkisaostuma kahvinkeittimessä on esimerkki vastaavasta ongelmasta arkielämässä. Massa- ja paperiteollisuudessa yksi hankalimmista kivettymien muodostajista on kalsiumoksalaatti, koska se on lähes liukenematonta ja sen aiheuttamat saostumat ovat erittäin vaikeasti poistettavia. Kalsiumoksalaatti on yleisesti tunnettu myös munuaiskivien aiheuttajana ihmisillä. Puu ja varsinkin sen kuori sisältää aina jonkin verran oksalaattia, mutta suurempi lähde on kuitenkin oksaalihappo jota muodostuu valkaistaessa massaa hapettavilla kemikaaleilla, kuten vetyperoksidilla. Kalsiumoksalaattia syntyy kun veden, puun ja lisäaineiden mukana prosessiin tuleva kalsium reagoi oksalaatin kanssa. Tässä väitöskirjatyössä tutkittiin oksaalihapon muodostumiseen ja kalsiumoksalaatin saostumiseen vaikuttavia tekijöitä valkaisu- ja saostumiskokeiden avulla. Tutkimuksen painopiste oli saostumien ehkäisemisessä puupitoisten painopaperien valmistuksessa. Työssä saadut tulokset osoittavat että oksaalihapon muodostumiseen ja kalsiumoksalaatin saostumiseen voidaan vaikuttaa sekä prosessiteknisten että märänpään kemian keinojen avulla. Tehokas puun kuorinta, optimoidut olosuhteet peroksidivalkaisussa, muiden liuenneiden ja kolloidisten aineiden hallinta sekä räätälöidyn kemian hyödyntäminen kalsiumoksalaattisaostumien torjunnassa ovat keskeisissä rooleissa ongelmien välttämiseksi. Väitöskirjatyön tuloksia voidaan hyödyntää massan valkaisulinjoja suunniteltaessa sekä kalsiumoksalaatin aiheuttamien ongelmien ratkaisemisessa. Tutkimusmenetelmiä, joita käytettiin saostumiskokeissa ja eri lisäaineiden vaikutusten arvioinnissa, voidaan hyödyntää massa- ja paperiteollisuuden lisäksi myös muilla alueilla, kuten sokeri- ja panimoteollisuudessa, joissa ongelma on myös yleinen.

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Herbicides used in Clearfield(r) rice system may persist in the environment, damaging non-tolerant crops sown in succession and/or rotation. These damages vary according to soil characteristics, climate and soil management. The thickness of the soil profile may affect carryover effect; deeper soils may allow these molecules to leach, reaching areas below the roots absorption zone. The aim of this study was to evaluate the effect of the thickness of soil profile in the carryover of imazethapyr + imazapic on ryegrass and non-tolerant rice, sown in succession and rotation to rice, respectively. Lysimeters of different thicknesses (15, 20, 30, 40, 50 and 65 cm) were constructed, where 1 L ha-1 of the imazethapyr + imazapic formulated mixture was applied in tolerant rice. Firstly, imidazolinone-tolerant rice was planted, followed by ryegrass and non-tolerant rice in succession and rotation, respectively. Herbicide injury, height reduction and dry weight of non-tolerant species were assessed. There was no visual symptoms of herbicide injury on ryegrass sown 128 days after the herbicide application; however it causes dry weight mass reduction of plants. The herbicides persist in the soil and cause injury in non-tolerant rice, sown 280 days after application, and the deeper the soil profile, the lower the herbicides injury on irrigated rice.

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Human serum albumin (HSA) is the most abundant protein in the intravascular compartment. It possesses a single thiol, Cys34, which constitutes ~80% of the total thiols in plasma. This thiol is able to scavenge plasma oxidants. A central intermediate in this potential antioxidant activity of human serum albumin is sulfenic acid (HSA-SOH). Work from our laboratories has demonstrated the formation of a relatively stable sulfenic acid in albumin through complementary spectrophotometric and mass spectrometric approaches. Recently, we have been able to obtain quantitative data that allowed us to measure the rate constants of sulfenic acid reactions with molecules of analytical and biological interest. Kinetic considerations led us to conclude that the most likely fate for sulfenic acid formed in the plasma environment is the reaction with low molecular weight thiols to form mixed disulfides, a reversible modification that is actually observed in ~25% of circulating albumin. Another possible fate for sulfenic acid is further oxidation to sulfinic and sulfonic acids. These irreversible modifications are also detected in the circulation. Oxidized forms of albumin are increased in different pathophysiological conditions and sulfenic acid lies in a mechanistic junction, relating oxidizing species to final thiol oxidation products.

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Hepatocellular carcinoma (HCC) is the third highest cause of cancer death worldwide. In general, the disease is diagnosed at an advanced stage when potentially curative therapies are no longer feasible. For this reason, it is very important to develop new therapeutic approaches. Retinoic acid (RA) is a natural derivative of vitamin A that regulates important biological processes including cell proliferation and differentiation. In vitro studies have shown that RA is effective in inhibiting growth of HCC cells; however, responsiveness to treatment varies among different HCC cell lines. The objective of the present study was to determine if the combined use of RA (0.1 µM) and cAMP (1 mM), an important second messenger, improves the responsiveness of HCC cells to RA treatment. We evaluated the proliferative behavior of an HCC cell line (HTC) and the expression profile of genes related to cancer signaling pathway (ERK and GSK-3β) and liver differentiation (E-cadherin, connexin 26 (Cx26), and Cx32). RA and cAMP were effective in inhibiting the proliferation of HTC cells independently of combined use. However, when a mixture of RA and cAMP was used, the signals concerning the degree of cell differentiation were increased. As demonstrated by Western blot, the treatment increased E-cadherin, Cx26, Cx32 and Ser9-GSK-3β (inactive form) expression while the expression of Cx43, Tyr216-GSK-3β (active form) and phosphorylated ERK decreased. Furthermore, telomerase activity was inhibited along treatment. Taken together, the results showed that the combined use of RA and cAMP is more effective in inducing differentiation of HTC cells.

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Hyperuricemia has been associated with hypertension, diabetes mellitus, and metabolic syndrome. We studied the association between hyperuricemia and glycemic status in a nonrandomized sample of primary care patients. This was a cross-sectional study of adults ≥20 years old who were members of a community-based health care program. Hyperuricemia was defined as a value >7.0 mg/dL for men and >6.0 mg/dL for women. The sample comprised 720 participants including controls (n=257) and patients who were hypertensive and euglycemic (n=118), prediabetic (n=222), or diabetic (n=123). The mean age was 42.4±12.5 years, 45% were male, and 30% were white. The prevalence of hyperuricemia increased from controls (3.9%) to euglycemic hypertension (7.6%) and prediabetic state (14.0%), with values in prediabetic patients being statistically different from controls. Overall, diabetic patients had an 11.4% prevalence of hyperuricemia, which was also statistically different from controls. Of note, diabetic subjects with glycosuria, who represented 24% of the diabetic participants, had a null prevalence of hyperuricemia, and statistically higher values for fractional excretion of uric acid, Na excretion index, and prevalence of microalbuminuria than those without glycosuria. Participants who were prediabetic or diabetic but without glycosuria had a similarly elevated prevalence of hyperuricemia. In contrast, diabetic patients with glycosuria had a null prevalence of hyperuricemia and excreted more uric acid and Na than diabetic subjects without glycosuria. The findings can be explained by enhanced proximal tubule reabsorption early in the course of dysglycemia that decreases with the ensuing glycosuria at the late stage of the disorder.

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Commercial cashew apple juice is widely accepted in the Brazilian market. Cashew apple has high content of ascorbic acid, an important nutrient to human beings. Ascorbic acid content in food can be affected by processing and storage conditions. Commercial cashew apple juice samples, ready-to-drink and concentrated, were analyzed. The ascorbic acid content, total titratable acidity, total soluble solids, and pH of the juices were determined during storage at 4 °C after the containers were opened. The ascorbic acid content presented a great variability among the samples analyzed ranging from 37.3 to 46.3 mg.100 mL-1 in ready-to-drink juices and from 75.7 to 152 mg.100 mL-1 in concentrated juices. The storage of commercial cashew apple juices for 48 hours at 4 °C resulted in ascorbic acid losses of up to 8.8% for concentrated and 6.4% for ready-to-drink juices. The other parameters remained stable during storage. The results of this study point to the importance of considering ascorbic acid losses in commercial cashew apple juices which occurs after opening but before the expiration date expires.