270 research outputs found
Biosynthesis Coupled to the Extraction of Geranyl Acetate in a Liquid-Gas System: Optimization of the Transesterification Reaction and Modeling of the Transfer
The objective of this paper was to study the production and the mass transfer of geranyl acetate known for its interesting green odor properties. Lipase-catalyzed geranyl acetate production via transesterification reaction with ethyl acetate in organic solvent was investigated. The production was catalyzed by using immobilized lipase from Rhizomucor miehei, and the recovery was achieved by using solid phase microextraction (SPME) fiber system (50/30 Όm DVB/Carboxen/PDMS Coating). The effects of different reaction parameters on transesterification including the enzyme concentration, the substrate molar ratio, the added water, and the reaction time were firstly optimized. A higher yield of 82 % was achieved under near-anhydrous conditions at 55 °C by using an enzyme concentration of 6 % (w/w reactants), a molar ratio of geraniol to ethyl acetate of 1:5, and a reaction time of 6 h. Immobilized lipase was repeatedly used for four cycles with no decrease in reaction yield. The mass transfer of geranyl acetate from the organic to gas phase was studied theoretically and experimentally, and a transfer yield of 52.3 % was obtained. The simulation showed that the Fuller-Schettler-Giddings model exhibited good correlation with the experimental data
Effect of dietary vitamin E supplementation on lipid and colour stability of chicken thigh meat
Lipid and myoglobin oxidation are major causes of meat quality deterioration during storage of fresh chicken meat. Our objective is to determine the effects of dietary -tocopherol supplementation on lipid and colour stability of fresh chicken thigh meat exposed in a supermarket shopwindow or stored in a refrigerator. Chickens were fed with diets containing 25 (control), 100, 200 or 300 mg vitamin E/kg of food for 20 days before slaughtering. Peroxide value (PV) and oxidation products specific extinctions (K232 and K270), chosen as markers for oxidative deterioration of lipids, were lower in chicken meat from animals supplemented with 200 or 300 mg vitamin E than that of the control meat upon storage during 5 days in a shopwindow (p < 0.01) or 9 days in a refrigerator (p < 0.01). Vitamin E dietary supplementation (200 mg vitamin E/kg of food) reduced oxidation products formation in fresh thighs meat but had no significant impact on colour analysed by value redness (a*) measurements
Investigation of genetic variability related to the in vitro floral hermaphrodism induction in Date palm (Phoenix dactylifera L.)
This paper reports on a molecular analysis study conducted on Date palm flowers from the Deglet Nour cultivar to investigate putative genetic variability related to the in vitro floral hermaphrodism induction. Natural male and female as well as hermaphrodite ones that were produced in vitro through the hormonal treatment of female flowers were submitted to ISSR-PCR analysis. Microsatellite based amplification (ISSR) was applied on genomic DNA from inflorescences taken at different periods of hormonal treatment corresponding to the various deviation stages to search for putative variations that may have occurred on the initial genome due to the application of plant growth regulators. Several amplification bands were purified, cloned, and sequenced. The results revealed that hormonal treatment entailed no detectable genetic variation in the treated Date palm flowers. Two of the selected and ISSR-PCR amplified DNA fragments showed however, possible links with flowering regulation. The findings indicate that these sequences are potential candidate gene markers that may enhance our understanding of flower development and sex identification in this species.Key words: Date palm, female inflorescences, hermaphrodite flowers, in vitro culture, ISSR, sex identification
Composition and Anticoagulant Potential of Chondroitin Sulfate and Dermatan Sulfate from Inedible Parts of Garfish (Belone belone)
Glycosaminoglycans (GAGs) play a crucial role due to their significant biomedical functions. Chondroitin sulfate (CS) and dermatan sulfate (DS), the main representative family of GAGs, were extracted and purified from garfish (Belone belone) by-products, i.e., skin (GSB), bones (GCB), and heads (GHB), and their composition and anticoagulant activity were investigated. CS/DS were purified by ion-exchange chromatography with yields of 8.1% for heads, 3.7% for skin, and 1.4% for bones. Cellulose acetate electrophoresis was also explored for analyzing the extracted CS/DS. Interestingly, GHB, GSB, and GCB possessed sulfate contents of 21 ± 2%, 20 ± 1%, and 20 ± 1.5%, respectively. Physico-chemical analysis showed that there were no significant differences (p > 0.05) between the variances for sulfate, uronic acid, and total sugars in the GAGs extracted from the different parts of fish. Disaccharide analysis by SAX-HPLC showed that the GSB and GCB were predominately composed of ÎDi-4S [ÎUA-GalNAc 6S] (74.78% and 69.22%, respectively) and ÎDi-2,4S [ÎUA2S-GalNAc 4S] (10.92% and 6.55%, respectively). However, the GHB consisted of 25.55% ÎDi-6S [ÎUA-GalNAc 6S] and 6.28% ÎDi-2,6S [ÎUA2S-GalNAc 4S]. Moreover, classical anticoagulation tests were also used to measure their anticoagulant properties in vitro, which included the activated partial thromboplastin time, prothrombin time, and thrombin time. The CS/DS isolated from garfish by-products exhibited potent anticoagulant effects. The purified CS/DS showed exceptional anticoagulant properties according to this research and can be considered as a new agent with anticoagulant properties
Global burden of human brucellosis : a systematic review of disease frequency
BACKGROUND: This report presents a systematic review of scientific literature published between 1990-2010 relating to the frequency of human brucellosis, commissioned by WHO. The objectives were to identify high quality disease incidence data to complement existing knowledge of the global disease burden and, ultimately, to contribute towards the calculation of a Disability-Adjusted Life Years (DALY) estimate for brucellosis.METHODS/PRINCIPAL FINDINGS: Thirty three databases were searched, identifying 2,385 articles relating to human brucellosis. Based on strict screening criteria, 60 studies were selected for quality assessment, of which only 29 were of sufficient quality for data analysis. Data were only available from 15 countries in the regions of Northern Africa and Middle East, Western Europe, Central and South America, Sub-Saharan Africa, and Central Asia. Half of the studies presented incidence data, six of which were longitudinal prospective studies, and half presented seroprevalence data which were converted to incidence rates. Brucellosis incidence varied widely between, and within, countries. Although study biases cannot be ruled out, demographic, occupational, and socioeconomic factors likely play a role. Aggregated data at national or regional levels do not capture these complexities of disease dynamics and, consequently, at-risk populations or areas may be overlooked. In many brucellosis-endemic countries, health systems are weak and passively-acquired official data underestimate the true disease burden.CONCLUSIONS: High quality research is essential for an accurate assessment of disease burden, particularly in Eastern Europe, the Asia-Pacific, Central and South America and Africa where data are lacking. Providing formal epidemiological and statistical training to researchers is essential for improving study quality. An integrated approach to disease surveillance involving both human health and veterinary services would allow a better understand of disease dynamics at the animal-human interface, as well as a more cost-effective utilisation of resources
Milk yield estimation during suckling using the double oxytocin injection-milking and the double weighing-suckling methods in dairy goats
The aim was to verify the validity of the double oxytocin-milking (DOT) method as milk
yield estimator during the suckling period of lactating dairy goats. To this end, it was necessary
to determine whether the weighing suckling weighing (WSW) and DOT methods of
milk yield estimation satisfied the criteria to be considered valuable, the accuracy between
both methods and the suitability of DOT to evaluate actual milk. At parturition, sixty lactating
Murciano Granadina breed goats were separated into 2 groups, in mixed (MS; n = 24)
and artificial rearing (ARS; n = 36) management systems. Until the sixth week of lactation
(weaning), MS goats suckled one kid while kids from ARS goats were artificially reared;
moreover, goats in both systems were submitted to once-a-day milking. Once per week,
actual milk yield for ARS goats and potential milk yield were recorded using DOT method
for all goats, except for 12 goats in ARS which remained as a control. Twelve goats from each
management system were used to evaluate diurnal variation in milk production (DVM) by
DOT method for 6 consecutive days in week 4 of lactation. No difference in DVM was found
by DOT method in 4-h milk production of goats in MS (P = 0.099) or ARS (P = 0.220), which
allowed sixfold multiplication of milked milk volume to obtain potential milk per day. ARS
goats subjected to a weekly DOT and control group goats showed a similar (P = 0.379) lactation
curve for the first 6 weeks of lactation. The DOT method slightly overestimated (3.4%,
P = 0.005) the milk yield evaluated by WSW method for goats under an MS, but fitted the
actual milk obtained by common milk records for the group of goats in an ARS submitted
to the DVM test (P = 0.357) and the group in ARS alone (P = 0.163). The DOT method applied
for 8 consecutive days led to a drop of 6 12% in milk yield during the following week for
both production systems. In conclusion, DOT was an accurate method to estimate milk
yield during the first weeks of lactation both in MS and ARS under the conditions of this
experiment.
© 2013 Elsevier B.V. All rights reserved.FernĂĄndez MartĂnez, N.; Balasch Parisi, S.; PĂ©rez Baena, I.; RodrĂguez Garcia, M.; Peris Ribera, CJ. (2013). Milk yield estimation during suckling using the double oxytocin injection-milking and the double weighing-suckling methods in dairy goats. Small Ruminant Research. 112(1-3):181-185. doi:10.1016/j.smallrumres.2012.12.023S1811851121-
Identification of multiple root disease resistant wheat germplasm against cereal nematodes and dryland root rot and their validation in regions of economic importance
HistĂłria da literatura portuguesa coordenada por Giulia Lanciani - primeiras pĂĄginas de um total pp. 7-108)HistĂłria literĂĄria do sĂ©culo XVIII portuguĂȘsGoverno de Portuga
Rhaponticum acaule (L) DC essential oil: chemical composition, in vitro antioxidant and enzyme inhibition properties
Background: α-glucosidase is a therapeutic target for diabetes mellitus (DM) and α-glucosidase inhibitors play a
vital role in the treatments for the disease. Furthermore, xanthine oxidase (XO) is a key enzyme that catalyzes
hypoxanthine and xanthine to uric acid which at high levels can lead to hyperuricemia which is an important cause
of gout. Pancreatic lipase (PL) secreted into the duodenum plays a key role in the digestion and absorption of fats.
For its importance in lipid digestion, PL represents an attractive target for obesity prevention.
Methods: The flowers essential oil of Rhaponticum acaule (L) DC (R. acaule) was characterized using gas
chromatography-mass spectrometry (GC-MS). The antioxidant activities of R. acaule essential oil (RaEO) were also
determined using 2,2â-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), reducing power,
phosphomolybdenum, and DNA nicking assays. The inhibitory power of RaEO against α-glucosidase, xanthine
oxidase and pancreatic lipase was evaluated. Enzyme kinetic studies using Michaelis-Menten and the derived
Lineweaver-Burk (LB) plots were performed to understand the possible mechanism of inhibition exercised by the
components of this essential oil.
Results: The result revealed the presence of 26 compounds (97.4%). The main constituents include germacrene D
(49.2%), methyl eugenol (8.3%), (E)-ÎČ-ionone (6.2%), ÎČ-caryophyllene (5.7%), (E,E)-α-farnesene (4.2%),
bicyclogermacrene (4.1%) and (Z)-α-bisabolene (3.7%). The kinetic inhibition study showed that the essential oil
demonstrated a strong α-glucosidase inhibiton and it was a mixed inhibitor. On the other hand, our results
evidenced that this oil exhibited important xanthine oxidase inhibitory effect, behaving as a non-competitive
inhibitor. The essential oil inhibited the turkey pancreatic lipase, with maximum inhibition of 80% achieved at
2 mg/mL. Furthermore, the inhibition of turkey pancreatic lipase by RaEO was an irreversible one.
Conclusion: The results revealed that the RaEO is a new promising potential source of antioxidant compounds,
endowed with good practical applications for human health.
Keywords: α-glucosidase, Antioxidant activity, Chemical composition, Pancreatic lipase inhibition, Rhaponticum
acaule essential oil, Xanthine oxidase
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