Water sorption enthalpy-entropy compensation based on isotherms of plum skin and pulp

The net isosteric heat and entropy of water sorption were calculated for plum, based on sorption isotherms obtained by the static gravimetric method at different temperatures (20 to 70 degrees C). The Guggenheim-Anderson-deBoer model was applied to the experimental data giving a good agreement between experimental and calculated values. The net isosteric heat of water sorption, estimated by applying Claussius-Clapeyron equation to sorption isotherms, was found to be different for plum skin and pulp, mainly at low moisture contents, and could be well adjusted by an empirical exponential relationship. Plots of enthalpy in contrast to entropy provided the isokinetic temperatures for skin and pulp, indicating an enthalpy-controlled sorption process. Thermodynamic data on water sorption for plums are not found in literature, as opposed to prunes for which the data are abundant.

Karyotype studies of some species of Dalechampia plum. (Euphorbiaceae)

Karyotype studies in eight species of Dalechampia, including 10 natural populations, revealed chromosome numbers (2n = 36, 46, 138 and 198) differing from two numbers cited in the literature (2n = 44 and 72). The basic number x = 6, as in the genus Acalypha, may be considered ancestral in Dalechampia. Analysis of Chromosome number, haploid chromosome length and karyotype symmetry suggests that the major chromosome mechanism acting in karyotype evolution of Dalechampia is polyploidy, but differences in chromosome morphology may be caused by chromosome rearrangements.

Sorption isotherm, glass transitions and state diagram for freeze-dried plum skin and pulp

Differential scanning calorimetry (DSC) was used to determine phase transitions of freeze-dried plums. Samples at low and intermediate moisture contents, were conditioned by adsorption at various water activities (0.11≤a w≤0.90) at 25°C, whereas in the high moisture content region (a w>0.90) samples were obtained by direct water addition, with the resulting sorption isotherm being well described by the Guggenheim-Anderson-deBoer (GAB) model. Freeze-dried samples of separated plum skin and pulp were also analysed. At a w≤0.75, two glass transitions were visible, with the glass transition temperature (T g) decreasing with increasing a w due to the water plasticising effect. The first T g was attributed to the matrix formed by sugars and water. The second one, less visible and less plasticised by water, was probably due to macromolecules of the fruit pulp. The Gordon-Taylor model represented satisfactorily the matrix glass transition curve for a w≤0.90. In the higher moisture content range T g remained practically constant around T g′ (-57.5°C). Analysis of the glass transition curve and the sorption isotherm indicated that stability at a temperature of 25°C, would be attained by freeze dried plum at a water activity of 0.04, corresponding to a moisture content of 12.9% (dry basis). © 2006 SAGE Publications.

Enraizamento de estacas lenhosas e semilenhosas de cultivares de ameixeira com várias concentrações de ácido indolbutírico

Para avaliar o potencial de enraizamento de estacas de ramos lenhosos e semilenhosos de cultivares de ameixeira (Carmesin, Gema de Ouro, Januária e Reubennel), utilizou-se aplicação exógena de ácido indolbutírico (IBA) em diferentes concentrações (0; 1000; 2000 e 3000mg L-1). O trabalho foi desenvolvido na Universidade Federal de Lavras (UFLA) (Lavras-MG), em 1997. Após os tratamentos, as estacas foram plantadas em areia lavada e colocadas em casa de sombreamento (lenhosas) e em casa de vegetação (semilenhosas) para enraizar. Foram avaliadas as variáveis porcentagem de enraizamento, número e comprimento de raízes. As maiores porcentagens de enraizamento foram obtidas com estacas semilenhosas da cultivar Januária (54,62%). A aplicação de IBA favoreceu o enraizamento, a formação de maior número de raízes e o comprimento de raízes nas estacas semilenhosas.

Strains of Xylella fastidiosa rapidly distinguished by arbitrarily primed-PCR

Genomic DNAs isolated from strains of Xylella fastidiosa that caused citrus variegated chlorosis, coffee leaf scorch, Pierce's Disease of grapevine, and plum leaf scorch were analyzed by arbitrarily primed polymerase chain reaction. Purified DNA was amplified under nonstringent conditions with single primers 21 nucleotides (nt) long. Thirty-nine amplification products were observed that were useful to distinguish among the strains and to derive a similarity matrix and construct a phenogram showing possible relationships among the strains. Strains isolated from diseased coffee and citrus in Brazil were closely related to each other (coefficient of similarity of 0.872), but only distantly related to a strain isolated from diseased grapevine in the USA (coefficient of similarity of 0.650). Strains of Xylella fastidiosa isolated from diseased plums in the USA and Brazil clustered with strains from different hosts isolated from their respective countries of origin. Thus, there may be two quite dissimilar clusters of strains of Xylella fastidiosa, one in North America and the other in South America. Each cluster contains strains that can cause disease in plum. The methods described provide a convenient and rapid method to distinguish between strains of Xylella fastidiosa that cause diseases of coffee and citrus in the same region of Brazil. This has not been possible previously. This will potentially enable the two strains to be distinguished in alternate hosts or in insect vectors.

Strain variability in the DNA immigration control region (ICR) of Xylella fastidiosa

The genome of the bacterium Xylella fastidiosa contains four ORFs (XF2721, XF2725, XF2739 and XF0295) related to the restriction modification type I system, ordinarily named R-M. This system belongs to the DNA immigration control region (ICR). Each CIRF is related to different operon structures, which are homologues among themselves and with subunit Hsd R from the endonuclease coding genes. In addition, these ORFs are highly homologous to genes in Pseudomonas aeruginosa, Methylococcus capsulatus str. Bath, Legionella pneumophila, Helicobacter pylori, Xanthomonas oryzae pv. Oryzae and Silicibacter pomeroyi, as well as to genes from X. fastidiosa strains that infect grapevine, almond and oleander plants. This study was carried out on R-M ORFs from forty-three X. fastidiosa strains isolated from citrus, coffee, grapevine, periwinkle, almond and plum trees, in order to assess the genetic diversity of these loci through PCR-RFLP. PCR-RFLP analysis of the four ORFs related to the R-M system from these strains enabled the detection of haplotypes for these loci. When the haplotypes were defined, wide genetic diversity and a large range of similar strains originating from different hosts were observed. This analysis also provided information indicating differences in population genetic structures, which led to detection of different levels of gene transfer among the groups of strains. (c) 2005 Elsevier SAS. All rights reserved.

Effect of pectinolitic enzymes on the physical properties of caja-manga (Spondias cytherea Sonn.) pulp

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of the use of Syzygium cumini fruit extract as an antioxidant additive in orange juice and its sensorial impact

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

An evaluation of the genetic diversity of Xylella fastidiosa isolated from diseased citrus and coffee in São Paulo, Brazil

Strains of Xylella fastidiosa, isolated from sweet orange trees (Citrus sinensis) and coffee trees (Coffea arabica) with symptoms of citrus variegated chlorosis and Requeima do Cafe, respectively, were indistinguish able based on repetitive extragenic palindromic polymerase chain reaction (PCR) and enterobacterial repetitive intergenic consensus PCR assays. These strains were also indistinguishable with a previously described PCR assay that distinguished the citrus strains from all other strains of Xylella fastidiosa. Because we were not able to document any genomic diversity in our collection of Xylella fastidiosa strains isolated from diseased citrus, the observed gradient of increasing disease severity from southern to northern regions of São Paulo State is unlikely due to the presence of significantly different strains of the pathogen in the different regions. When comparisons were made to reference strains of Xylella fastidiosa isolated from other hosts using these methods, four groups were consistently identified consistent with the hosts and regions from which the strains originated: citrus and coffee, grapevine and almond, mulberry, and elm, plum, and oak. Independent results from random amplified polymorphic DNA (RAPD) PCR assays were also consistent with these results; however, two of the primers tested in RAPD-PCR were able to distinguish the coffee and citrus strains. Sequence comparisons of a PCR product amplified from all strains of Xylella fastidiosa confirmed the presence of a CfoI polymorphism that can be used to distinguish the citrus strains from all others. The ability to distinguish Xylella fastidiosa strains from citrus and coffee with a PCR-based assay will be useful in epidemiological and etiological studies of this pathogen.

Ausência de patogenicidade de Xylella fastidiosa da escaldadura da folha da ameixeira na cultivar de pessegueiro flordasun

Xylella fastidiosa associated to plum leaf scald is reported to belong to the same group of the strain that causes the phony disease of peach. Plants of plum cultivars Santa Rosa and Harry Pickstone and peach cultivar Flordasun, grafted on peach rootstock, were inoculated by using buds collected from plum plants severely infected with X. fastidiosa. Peach plants did not develop symptoms of phony disease, after four years in the greenhouse. In contrast, plum plants from both cultivars inoculated either in the rootstock or in the canopy developed leaf scald symptoms. DAS-ELISA tests with antibody against X. fastidiosa and isolation on BCYE medium indicated the presence of the bacterium in plum tissues. These tests were negative for Flordasun peach for both stem and root samples.

Transposon Tn1721 distribution among strains of Xylella fastidiosa

Transposons are mobile genetic elements found within the genomes of various organisms including bacteria, fungi, plants and animals. Fragments of the transposon Tn1721 were found included in the genome of Xylella fastidiosa strain 9a5c. Regions from such fragments were PCR-amplified using specially designed primers (TNP1 and TNP2). In order to detect insertions of the Tn1721 element, both primers were used and one of them included a region of the transposon (TNP1) and the other one had the right repeat and part of the bacterial chromosome (TNP2). The PCR products obtained from strain 9a5c were used as a pattern for fragment size comparisons when DNA samples from other X. fastidiosa strains were used as template for the PCR assays. Differences were observed concerning the PCR products of such amplifications when some X. fastidiosa strains isolated from grapevine and plum were used. For the citrus-derived strains only the strains U187d and GP920b produced fragments with different sizes or weak band intensity. Such variations in the X. fastidiosa genome related to disrupted Tn1721 copies are probably due to the possibility of such a transposon element being still able to duplicate even after deletion events might have taken place and also because the bacterial strains in which the main differences were detected are derived from different host plants cultivated under different climate conditions from the one used as reference. © 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

Ação farmacológica de Syzygium cumini (L.) skeels

Natural products have received new interest recently, maybe in men's attempt to turn into the nature for the prevention and the relief of diseases, mainly because of those untreated by the traditional medicine. Syzygium cumini (L.) Skeels, popularly known as 'jambolão, is a well-known plant by several pharmacological actions so much in the popular use as in the scientific literature. In this search antidiabetic, anti-diarrhoeal, anti-inflammatory, antioxidant and antimicrobial activities of 'jambolão' were described, among other actions.

Caracterização de Puccinia psidii, identificação de mirtáceas diferenciadoras de raças fisiológicas e estudos anatômicos do limbo foliar relacionados à resistência

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Syzygium cumini (L.) Skeels: avaliação da qualidade, estudo morfo-anatômico, estudo da atividade antimicrobiana, conservante, genotóxica, mutagênica, citotóxica e incorporação em formulações cosméticas para uso tópico

Pós-graduação em Ciências Farmacêuticas - FCFAR