Partial purification and characterization of pectin methylesterase from acerola (Malpighia glabra L.)     

De Assis SA  Martins AB  Guaglianoni DG  De Faria Oliveira OM 《Journal of agricultural and food chemistry》2002,50(14):4103-4107

The enzyme pectin methylesterase (PME) is present in acerola fruit and was partially purified by gel filtration on Sephadex G-100. The results of gel filtration showed different PME isoforms. The total PME (precipitated by 70% salt saturation) and one of these isoforms (fraction from Sephadex G-100 elution) that showed a molecular mass of 15.5 +/- 1.0 kDa were studied. The optimum pH values of both forms were 9.0. The total and the partially purified PME showed that PME specific activity increases with temperature. The total acerola PME retained 13.5% of its specific activity after 90 min of incubation at 98 degrees C. The partially purified acerola (PME isoform) showed 125.5% of its specific activity after 90 min of incubation at 98 degrees C. The K(m) values of the total PME and the partially purified PME isoform were 0.081 and 0.12 mg/mL, respectively. The V(max) values of the total PME and the partially purified PME were 2.92 and 6.21 micromol/min/mL/mg of protein, respectively.  相似文献   

Relationship of host recurrence in fungi to rates of tropical leaf decomposition     

Mirna E. Santana  D. Jean Lodge  Patricia Lebow 《Pedobiologia》2005,49(6):23-564

Here we explore the significance of fungal diversity on ecosystem processes by testing whether microfungal ‘preferences’ for (i.e., host recurrence) different tropical leaf species increases the rate of decomposition. We used pairwise combinations of γ-irradiated litter of five tree species with cultures of two dominant microfungi derived from each plant in a microcosm experiment. The experiment was designed to test whether early leaf decomposition rates differed depending on relationships between the leaf litter from which the fungi were derived (i.e., the source plant) and the leaf substrata decomposed by these fungi in microcosms. Relationships tested were phylogenetic relatedness between the source and substratum leaves, and similarity in litter quality (lignin, N and P) between the source and substratum. We found a significant interaction between microfungi and leaf species (P<0.0001), and differences among the four classes of source–substratum relationships were highly significant (P=0.0004). Combinations in which fungal source leaves were of the same species or family as the substratum, or the fungal source resembled the substratum in quality had marginally faster decomposition than when the fungal source and substratum leaves were mismatched (i.e., unrelated and of dissimilar quality). In some microcosms, a basidiomycete contaminant had a strong additive effect on decomposition of Croton poecilanthus leaves resulting in faster decomposition than with microfungi alone (P<0.0001). Comparisons among leaf–microfungal combinations were made after the effect of the basidiomycete covariate was adjusted to zero. The data on microfungi suggest differential abundance in particular hosts, which contributes to species diversity of decomposer fungi in tropical forests, affects rates of decomposition.  相似文献   

Comparison of Analytical Methods for Quantifying the Levels of Lead,Cadmium, Chromium,and Nickel in Mineral Fertilizers and Industrial By-products     

Camila Prado Cenciani de Souza  Cleide Aparecida de Abreu  Cristiano Alberto de Andrade  Aline Renee Coscione Gomes  José Francisco da Cunha 《Communications in Soil Science and Plant Analysis》2015,46(4):34-56

The control of contaminants in fertilizers and industrial by-products is fundamental to safe food production, and it requires low-cost, reliable test methods. The aim of this study was to evaluate the performance of the USEPA 3051a and alternative analytical methods [concentrated hydrochloric acid (HCl), 10 percent HCl, 10 percent sulfuric acid (H₂SO₄), and 50 mmol L^?1 diethylenetriaminepentaacetic acid (DTPA)] for quantifying the levels of lead, cadmium, chromium, and nickel in zinc and/or copper sources. The sample digestions with concentrated HCl, H₂SO₄, and nitric acid (HNO₃) (USEPA 3051a) were heated. Extraction without heating and stirring was employed in 10 percent HCl and 50 mmol L^?1 DTPA methods. The Graybill’s modified F-test, t-test for mean error, and the linear correlation coefficient analysis were used to compare test method performance. Equivalent results to USEPA 3051a were found with the following methods: DTPA for the extraction of lead in zinc sources and concentrated HCl and H₂SO₄ for the extraction of cadmium and chromium in copper sources. However, the absolute values of cadmium, chromium, and nickel recovered by the use of H₂SO₄ were greater regardless of the source. The greater extraction of contaminants in the evaluated methods suggests that there is need to review the official method if the aim is to quantify the total levels of these elements in raw materials and mineral fertilizers.  相似文献   

Interaction of curcumin and bixin with β-cyclodextrin: complexation methods, stability, and applications in food     

Marcolino VA  Zanin GM  Durrant LR  Benassi Mde T  Matioli G 《Journal of agricultural and food chemistry》2011,59(7):3348-3357

This work aimed to compare methods for the formation of complexes of bixin and curcumin with β-cyclodextrin (β-CD) and to evaluate the stability of the complexes formed by these methods and their food applications. The stoichiometric relationship between curcumin and β-CD was 1:2 and that between bixin and β-CD was 1:1. Curcumin-β-CD and bixin-β-CD complexes formed by kneading, coprecipitation, and simple mixing were evaluated by differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), or nuclear magnetic resonance (NMR-H). For both curcumin and bixin, the best method of complexation was coprecipitation. Complexation of colorants with β-CD promoted an intensification of color and increased water solubility; however, stabilization in the presence of light occurred only for bixin. Application of curcumin-β-CD in cheese and yogurt and bixin-β-CD in the curd did not alter the initial characteristics of the products, which were sensorialy well accepted. Therefore, the complexation of these natural colorants with β-CD favors their use in low-fat foods, broadening the field of industrial application.  相似文献   

Lidocaine effects on corneal endothelial cell ultrastructure     

Schellini SA  Creppe MC  Gregório EA  Padovani CR 《Veterinary ophthalmology》2007,10(4):239-244

The purpose of this study was to determine whether intracameral commercial lidocaine 2% induces alterations on the rabbit corneal endothelium. Forty white rabbits received different substances inside the anterior chamber: group (G)1, no substance; G2 and G3 received lidocaine 2% with preservative in aqueous solution; G4 and G5, lidocaine 2% with preservative in gel solution; G6 and G7, the anesthetic preservative (metilparahydroxybenzoate 0.1%); and G8 and G9, lidocaine 2% without preservative in aqueous solution. The animals from G2, 4, 6 and 8 were sacrificed after 1 h, and from G3, 5, 7 and 9 after 24 h after injection of the substance inside the anterior chamber. The corneas were clinically evaluated and assessed by transmission and scanning electron microscopy. G1, 2, 6, 7, 8 and 9 animals had very similar characteristics in clinical, ultrastructural and morphometric evaluations; the G3 and G4 animals showed discrete edema and one animal in G5 had intense corneal edema. We conclude that lidocaine 2% with preservative induces few ultrastructural alterations in the corneal endothelial cells.  相似文献   

New Insights of Turmeric Extract-Loaded PLGA Nanoparticles: Development,Characterization and In Vitro Evaluation of Antioxidant Activity     

Gonzales  Camila Maria  Dalmolin  Luciana Facco  da Silva  Kátia Aparecida  Slade  Natália Bueno Leite  Lopez  Renata Fonseca Vianna  Moreto  Jeferson Aparecido  Schwarz  Kélin 《Plant foods for human nutrition (Dordrecht, Netherlands)》2021,76(4):507-515

Here, we presented new insights of the development of poly(lactic-co-glycolic acid) nanoparticles containing turmeric compounds (turmeric-PLGA-NPs) using emulsion-solvent evaporation method. The nanoparticulate system was characterized by size, zeta potential, morphology, release profile, partition parameter, stability and encapsulation efficiency (%EE). Antioxidant activity studies were also evaluated. The Korsmeyer-Peppas model (M_t/M_∞ vs. t) was used to determine the release mechanisms of the studied system. Our results demonstrated the emulsion-solvent evaporation method was shown advantageous for producing turmeric-PLGA-NPs in the range of 145 nm with high homogeneity in size distribution, zeta potential of ?21.8 mV and %EE about 72%. Nanoparticles were stable over a period of one month. In vitro study showed a release of curcumin governed by diffusion and relaxation of the polymeric matrix. The partition parameter of the extract in relation to blank-PLGA-NPs was 0.111?±?0.008 M^?1, indicating a low affinity of curcumin for the polymer matrix. Antioxidant ability of the turmeric-PLGA-NPs in scavenging the radical 2,2-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS) was inferior to free turmeric extract and showed a concentration and time-dependent profile. The study concluded that PLGA nanoparticles are potential carriers for turmeric extract delivery.

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Symbiotic efficiency and identification of rhizobia that nodulate cowpea in a Rhodic Eutrudox     

Márcia Rufini  Michele Aparecida Pereira da Silva  Paulo Ademar Avelar Ferreira  Alice de Souza Cassetari  Bruno Lima Soares  Messias José Bastos de Andrade  Fatima Maria de Souza Moreira 《Biology and Fertility of Soils》2014,50(1):115-122

Cowpea (Vigna unguiculata (L.) Walp.) is one of the most important crops in the north and northeast regions of Brazil, where it is grown under the subsistence regime, mainly because of its adaptation to the local edaphoclimatic conditions. This species is an important legume in Brazil because of its significant nutritional value in the diet of low-income populations. Moreover, it is able to benefit from the process of biological nitrogen fixation, which leads to a significant reduction in production costs. The objective of this research was to evaluate the agronomic efficiency of bacterial strains approved by the Ministry of Agriculture, Livestock and Supply for commercial inoculant production when in symbiosis with cowpea in a Rhodic Eutrudox in Lavras, MG, as well as to identify and verify the efficiency of the native populations that nodulate cowpea. Agronomic efficiency of nitrogen-fixing nodulating bacterial strains (UFLA 03-84, INPA 03-11B, and BR 3267) in symbiosis with cowpea was evaluated in the field. Subsequently, the efficiency and diversity of isolates from the nodules obtained in the field were evaluated under greenhouse conditions. The genetic diversity of the efficient isolates was determined by partial sequencing of the 16S rRNA gene. Grain yields obtained by the inoculation of seeds in the field with the strains were similar to those of the controls without inoculation with and without mineral N addition indicating the existence of efficient native populations. In the native community, we identified isolates with similar or higher efficiency than the strains approved for cowpea inoculation and the control that received mineral N. The isolates subjected to partial sequencing of the 16S rRNA gene were phylogenetically related to the Bradyrhizobium genus.  相似文献   

Contribution of chlorogenic acids to the iron-reducing activity of coffee beverages     

Moreira DP  Monteiro MC  Ribeiro-Alves M  Donangelo CM  Trugo LC 《Journal of agricultural and food chemistry》2005,53(5):1399-1402

The iron-reducing activity of coffee beverages was determined by the ferric reducing antioxidant power (FRAP) assay. The influence on FRAP due to the degree of roasting (light, medium, and dark), species (Coffea arabica and Coffea robusta), and caffeine content (regular and decaffeinated) was investigated using ground and soluble coffee samples. The concentration of specific chlorogenic acids and caffeine in the beverages was determined by high-performance liquid chromatography and related to FRAP using Pearson correlation coefficients. All measurements were expressed per unit of soluble solids. Beverages prepared with ground coffee had, on average, 27% higher FRAP values than those prepared with soluble coffee (p < 0.05). In the former beverages, FRAP of C. robusta samples was significantly higher (on average, 50.3%) when compared to that of C. arabica samples, and FRAP values decreased with increasing degree of roasting (p < 0.05). A strong correlation (r > 0.91) was found between FRAP and the total content of chlorogenic acids, particularly that of the caffeoylquinic acid isomers. The iron-reducing activity of coffee beverages was not influenced by caffeine.  相似文献   

Soybean drought-stressed plants impair Anticarsia gemmatalis (Lepidoptera: Erebidae) midgut proteolytic activity and survival     

Faustino  Verônica Aparecida  de Almeida Barros  Rafael  da Silva Júnior  Neilier Rodrigues  Barbosa  Samuel Lessa  Vital  Camilo Elber  da Silva  Felipe Lopes  Cabrera  Yaremis Beatriz Meriño  Campos  Wellington Garcia  de Oliveira Ramos  Humberto Josué  de Almeida Oliveira  Maria Goreti 《Phytoparasitica》2021,49(4):491-500

Phytoparasitica - Soybean plants are exposed to multiple stresses during development. Co-occurring stresses can activate common defense pathways on plants, increasing end products concentrations,...  相似文献   

The Correlation between Age,Body Weight and Testicular Parameters in Murrah Buffalo Bulls Raised in Brazil     

Patrícia Aparecida Cardoso da LUZ  Paulo Ramos da Silva SANTOS  Cristiana ANDRIGHETTO  André Mendes JORGE  Ant?nio Chaves de ASSIS NETO 《The Journal of reproduction and development》2013,59(1):14-17

Buffalo are an economically important source for meat and milk production, especially in Brazil. However, important aspects of their biology remain unknown thus far. Herein, we describe the reproductive characteristics of male Murrah buffalo (Bubalus bubalis) raised under extensive management conditions by applying biometrics associated with testicular weight. We analyzed seven males, divided into two groups: G1, which consisted of four 18-month-old animals, and G2, which consisted of three 24-month-old animals. Testicular development occurs slowly in Murrah buffalo, suggesting a delay of sexual maturity. The biometric testicular parameters analyzed were scrotal circumference, testicular weight, testicular length, testicular width, testicular thickness and testicular circumference. Our data indicate strong correlations between SC, age and body weight, and additional significant relationships were identified between body weight, age and other testicular parameters. Thus, these parameters are suitable indicators when selecting bulls for breeding purposes.  相似文献