Time filter

Source Type

Region, Dominican Republic

Gimeno V.,ISA University | Diaz-Lopez L.,University of Moron | Simon-Grao S.,CSIC - Center of Edafology and Applied Biology of the Segura | Martinez V.,CSIC - Center of Edafology and Applied Biology of the Segura | And 2 more authors.
Plant Physiology and Biochemistry | Year: 2014

Scarcity of water is a severe limitation in citrus tree productivity. There are few studies that consider how to manage nitrogen (N) nutrition in crops suffering water deficit. A pot experiment under controlled-environment chambers was conducted to explore if additional N supply via foliar application could improve the drought tolerance of Citrus macrophylla L. seedlings under dry conditions. Two-month-old seedlings were subjected to a completely random design with two water treatments (drought stress and 100% water/field capacity). Plants under drought stress (DS) received three different N supplies via foliar application (DS: 0, DS+NH4NO3: 2% NH4NO3, DS+KNO3: 2% KNO3). KNO3-spraying increased leaf and stem DW as compared with DS+NH4NO3 and DS treatments. Leaf water potential (Ψw) was decreased by drought stress in all the treatments. However, in plants from DS+NH4NO and DS+KNO3, this was due to a decrease in the leaf osmotic potential, whereas the decrease in those from the DS treatment was due to a decrease in the leaf turgor potential. These responses were correlated with the leaf proline and K concentrations. DS+KNO3-treated plants had a higher leaf proline and K concentration than DS-treated plants. In terms of leaf gas exchange parameters, it was observed that net assimilation of CO2 (ACO2) was decreased by drought stress, but this reduction was much lower in DS+KNO3-treated plants. Thus, when all results are taken into account, it can be concluded that a 2% foliar-KNO3 application can enhance the tolerance of citrus plants to water stress by increasing the osmotic adjustment process. © 2014 Elsevier Masson SAS.

Daou C.,State Key Laboratory of Food Science and Technology | Daou C.,Jiangnan University | Daou C.,ISA University | Zhang H.,State Key Laboratory of Food Science and Technology | Zhang H.,Jiangnan University
Emirates Journal of Food and Agriculture | Year: 2013

Response surface methodology was used to optimize the processing parameters for extraction of total dietary fiber (TDF), insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) of defatted rice bran (DRB). The studied independent factors were concentration of NaOH solution (varying from 0.15 to 0.25 mol/L), soaking time (from 60 to 90 min), α-amylase enzyme-substrate (E: S) ratio (from 0.6:100 to 0.9:100 g: g of dry DRB) and alcalase enzyme concentration (from 3.5:100 to 4.7 g: g of dry DRB)) whereas; the dependent variables were extraction yield and purity of TDF, IDF and SDF. Therefore, the three- level four-factor Box-Behnken design was used to establish the optimum conditions and the generated regression quadratic polynomial models and adequacy of each dependent variable were significant (p < 0.0001) with regression coefficient R2 (> 0.90) and lack of-fit was not significant. Moreover, ANOVA showed that most of the linear, interaction and quadratic regression coefficient values were significant (p < 0.05). The optimum processing parameters observed for extraction of TDF, IDF and SDF with high yield and purity were: 0.15 mol/L NaOH solution concentration, 64.3 min soaking time, 0.68:100 and 3.52:100 (g: g) α-amylase and alcalase enzyme-substrate ratio (E: S), respectively. Moreover, the alkali pretreatment was the factor amongst the others that significantly (p<0.05) affected the purity of Fiber fractions but did not contribute to improve their yields.

Freitas F.,New University of Lisbon | Alves V.D.,ISA University | Reis M.A.M.,New University of Lisbon
Trends in Biotechnology | Year: 2011

A vast number of bacterial extracellular polysaccharides (EPSs) have been reported over recent decades, and their composition, structure, biosynthesis and functional properties have been extensively studied. Despite the great diversity of molecular structures already described for bacterial EPSs, only a few have been industrially developed. The main constraints to full commercialization are their production costs, mostly related to substrate cost and downstream processing. In this article, we review EPS biosynthetic and fermentative processes, along with current downstream strategies. Limitations and constraints of bacterial EPS development are stressed and correlation of bacterial EPS properties with polymer applications is emphasized. © 2011 Elsevier Ltd.

Chatelet B.,Ecole Normale Superieure de Lyon | Jeanneau E.,ISA University | Dutasta J.-P.,Ecole Normale Superieure de Lyon | Robert V.,CNRS Institute of Chemistry | And 2 more authors.
Catalysis Communications | Year: 2014

Various N-substituted azaphosphatranes have been prepared and successfully applied to the synthesis of styrene carbonates from CO2 and epoxides. Enhancement of the catalytic properties of the azaphosphatrane was achieved upon pre-organization of the active site through hydrogen-bonding. © 2014 Elsevier B.V. All rights reserved.

Silfrany R.O.,ISA University | Caba R.E.,ISA University | Solis De Los Santos F.,ISA University | Hanning I.,University of Tennessee at Knoxville
Journal of Food Protection | Year: 2013

In the Dominican Republic, poultry consumption per capita is greater than 34 kg of poultry meat per year. However, antibiotics, specifically the quinolone group, may be overused and can result in residues in the poultry meat. These residues are of concern because consumers may have allergies to antibiotics and antibiotic-resistant bacteria can develop from overuse of antibiotics in production. Little is known concerning this issue specifically for Santiago Province in the Dominican Republic. Thus, the main purpose of this research was to evaluate the incidence of residual quinolones in poultry meat and determine whether any residues detected were higher than the residue maximum limits (100 mg/kg) established by food industry authorities, including the U.S. Food and Drug Administration and European Food Safety Authority. A total of 135 samples of chicken breast were taken from different retail meat centers in the nine municipalities of Santiago Province (Santiago, Tamboril, Sabana Iglesia, Villa Bisonó , Puñal, Villa González, Licey, Jánico, and San José De Las Matas) and were analyzed using the Equinox test (Immunotec, Swanton, VT). Of the 135 samples analyzed, 50% from Sabana Iglesia, 20% from Licey, 20% from San Jose De Las Matas, and 6.25% from Santiago contained residues of quinolones higher than the residue maximum limits. No quinolone residues were detected in samples obtained from Janico, Punal, Tamboril, Villa Bisono, or Villa Gonzalez. The results of this investigation suggest that some poultry meat sold for human consumption in Santiago Province of the Dominican Republic contains quinolone residues and may represent a health risk to some consumers. Copyright ©, International Association for Food Protection.

Discover hidden collaborations