Sônia Maria de Stefano Piedade

In vitro morphogenesis of Cucumis melo var. inodorus

In vitro morphogenesis of C. melo L. var. inodorus was studied by the induction of adventitious buds and somatic embryos. Organogenesis was obtained from cotyledon segments and leaf discs in culture medium supplemented with benzylaminopurine (1 mg l−1) and somatic embryogenesis was induced in medium containing 2,4-dichlorophenoxyacetic acid (5 mg l−1) + thidiazuron (1 mg l−1). Through histological analysis it was possible to verify that in cotyledonary explants, protuberances that do not develop into well-formed shoot buds and leaf primordia are more frequently formed than complete shoot buds, resulting in a low frequency of plant recovery in the organogenic process. A high percentage of explants responded with the formation of somatic embryos; the microscopical analysis showed that the somatic embryos lacking well developed apical meristems had a low conversion rate into plants. Plant recovery was not obtained from leaf-disc explants, with high rates of contamination and formation of protuberances which did not develop into shoot buds. Histological sections showed the development of epidermis and leaf hairs, indicating those structures could be leaf primordia; however, these were not associated with a shoot apical meristem.In vitro morphogenesis of C. melo L. var. inodorus was studied by the induction of adventitious buds and somatic embryos. Organogenesis was obtained from cotyledon segments and leaf discs in culture medium supplemented with benzylaminopurine (1 mg l−1) and somatic embryogenesis was induced in medium containing 2,4-dichlorophenoxyacetic acid (5 mg l−1) + thidiazuron (1 mg l−1). Through histological analysis it was possible to verify that in cotyledonary explants, protuberances that do not develop into well-formed shoot buds and leaf primordia are more frequently formed than complete shoot buds, resulting in a low frequency of plant recovery in the organogenic process. A high percentage of explants responded with the formation of somatic embryos; the microscopical analysis showed that the somatic embryos lacking well developed apical meristems had a low conversion rate into plants. Plant recovery was not obtained from leaf-disc explants, with high rates of contamination and formation of protuberances which did not develop into shoot buds. Histological sections showed the development of epidermis and leaf hairs, indicating those structures could be leaf primordia; however, these were not associated with a shoot apical meristem.

Effects of pineapple byproduct and canola oil as fat replacers on physicochemical and sensory qualities of low-fat beef burger

Pineapple byproduct and canola oil were evaluated as fat replacers on physicochemical and sensory characteristics of low-fat burgers. Five treatments were performed: conventional (CN, 20% fat) and four low-fat formulations (10% fat): control (CT), pineapple byproduct (PA), canola oil (CO), pineapple byproduct and canola oil (PC). Higher water and fat retention and lower cooking loss and diameter reduction were found in burgers with byproduct addition. In raw burgers, byproduct incorporation reduced L*, a*, and C* values, but these alterations were masked after cooking, leading to products similar to CN. Low-fat treatments were harder, chewier, and more cohesive than full-fat burgers. However, in Warner Bratzler shear measurements, PA and PC were as tender as CN. In QDA, no difference was found between CN and PC. Pineapple byproducts along with canola oil are promising fat replacers in beef burgers. In order to increase the feasibility of use of pineapple byproduct in the meat industry, alternative processes of byproduct preparation should be evaluated in future studies.

Effects of different concentrations of passion fruit peel (Passiflora edulis) on the glicemic control in diabetic rat

Diabetes mellitus, an endocrine disorder, is the major cause of morbidity in developing countries, and it is considered the fourth leading cause of death worldwide. The conventional therapy for diabetes is insulin treatment. The peel of the Passion fruit is rich in fiber and prevents the absorption of carbohydrates, and thus can control and reduce the blood sugar rate. The objective of this study was to analyze the effect of the passion fruit peel flour on the glicemia of diabetic rats, as well as to study the probable action mechanisms. Wistar rats were used in the experiment and were offered the flours of the passion fruit peel in three concentrations: 5, 10, and 15%, and a casein diet as control. The most significant effect on the reduction of the glicemic rate was obtained with the 5% diet. The best values of hepatic glycogen were found in the 5 and 10% diets. The results of this study suggest that the 5% passion fruit flour diet was the one that provided the best reduction of blood glucose levels (59%) and the higher increase of the hepatic glycogen level (71%). The conversion of blood glucose into hepatic glycogen was considered the probable action mechanism involved.

Pineapple by-product and canola oil as partial fat replacers in low-fat beef burger: Effects on oxidative stability, cholesterol content and fatty acid profile

The effect of freeze-dried pineapple by-product and canola oil as fat replacers on the oxidative stability, cholesterol content and fatty acid profile of low-fat beef burgers was evaluated. Five treatments were performed: conventional (CN, 20% fat) and four low-fat formulations (10% fat): control (CT), pineapple by-product (PA), canola oil (CO), and pineapple by-product and canola oil (PC). Low-fat cooked burgers showed a mean cholesterol content reduction of 9.15% compared to the CN. Canola oil addition improved the fatty acid profile of the burgers, with increase in the polyunsaturated/saturated fatty acids ratio and decrease in the n-6/n-3 ratio, in the atherogenic and thrombogenic indexes. The oxidative stability of the burgers was affected by the vegetable oil addition. However, at the end of the storage time (120 days), malonaldehyde values of CO and PC were lower than the threshold for the consumers acceptance. Canola oil, in combination with pineapple by-product, can be considered promising fat replacers in the development of healthier burgers.

Penetration resistance in a latosol under different moisture and penetration speeds

The soil penetration resistance has been used to represent the compaction situation and several authors have attempted to relate the cone index (CI) with the bulk density . The importance of using the CI as source of information for decisions in agricultural activities, livestock and forestry manner , has become increasingly larger, which requires more knowledge about the penetrometers and penetrographs behavior. This study aimed to verify , in controlled laboratory conditions, the influence of soil water content and cone penetration rate to obtain the cone index, when density variation occurs. The soil was compacted by compression through a universal press cylinder which was specially designed to produce the test specimens. Bulk densities were determined from samples taken from the test specimens and their moisture content. The CI values obtained were between 0.258 and 4.776 MPa, measured in 4 moistures and 7 soil densities with 3 penetration speeds. It was concluded that the determination of IC is strongly influenced by the soil moisture but the penetration speed variation, used in this study , was not sufficient to influence the IC determination. However, the decrease in soil water content may increase the sensitiveness to detect a variation in bulk density by the use of cone index.

Cells of yeasts adhered in corn grains and the storage perspective for use as probiotic

O comportamento da viabilidade celular de leveduras e essencial quando se almeja utiliza-la como um probiotico e o veiculo que assegure esta propriedade ate o momento do consumo e particularmente. Sobre graos de milho, contendo 16 ou 20% de umidade, foram aplicadas leveduras desidratadas vivas, nas concentracoes de 1 e de 2%. A viabilidade celular foi avaliada nos periodos de 0, 15, 30, 90 e 110 dias de armazenamento. A viabilidade celular nas leveduras nao diferiu estatisticamente entre os tratamentos aos 30 dias em armazenamento, com a viabilidade media de 89,10%. A viabilidade media encontrada aos 90 dias de 72,20% foi menor do que aquelas nos tres primeiros periodos de armazenamento. Apos 110 dias de armazenamento foi de 61,14%. Conclue-se que leveduras apresentam viabilidade celular ate 110 dias em armazenamento sobre milho e que estes podem ser utilizados como um veiculo para a aplicacao da levedura como um probiotico.

Filme plástico perfurado em túneis baixos cultivados com alface

The present work was carried out with the objective to evaluate the micrometeorological conditions inside low tunnels cultivated with lettuce. A technique used to improve the ventilation inside the tunnels is the perforation of the plastic film, though still not very well known. Therefore, tunnels were tested without and with lettuce crop, with 0, 5, 10, 15 and 20% of perforated film area and in soil without tunnel, during spring. The meteorological variables used for the evaluation of the treatments were temperature and relative humidity of air. It was verified that the elevation of the temperature inside the protected atmosphere was inversely related to percentage of perforation contrary to the humidity loss for the external atmosphere. The production obtained under protected conditions was higher and of better quality.

Isolation, characterization, and evaluation of three Citrus sinensis-derived constitutive gene promoters

Key messageRegulatory sequences from the citrus constitutive genes cyclophilin (CsCYP), glyceraldehyde-3-phosphate dehydrogenase C2 (CsGAPC2), and elongation factor 1-alpha (CsEF1) were isolated, fused to the uidA gene, and qualitatively and quantitatively evaluated in transgenic sweet orange plants.AbstractThe 5′ upstream region of a gene (the promoter) is the most important component for the initiation and regulation of gene transcription of both native genes and transgenes in plants. The isolation and characterization of gene regulatory sequences are essential to the development of intragenic or cisgenic genetic manipulation strategies, which imply the use of genetic material from the same species or from closely related species. We describe herein the isolation and evaluation of the promoter sequence from three constitutively expressed citrus genes: cyclophilin (CsCYP), glyceraldehyde-3-phosphate dehydrogenase C2 (CsGAPC2), and elongation factor 1-alpha (CsEF1). The functionality of the promoters was confirmed by a histochemical GUS assay in leaves, stems, and roots of stably transformed citrus plants expressing the promoter-uidA construct. Lower uidA mRNA levels were detected when the transgene was under the control of citrus promoters as compared to the expression under the control of the CaMV35S promoter. The association of the uidA gene with the citrus-derived promoters resulted in mRNA levels of up to 60–41.8% of the value obtained with the construct containing CaMV35S driving the uidA gene. Moreover, a lower inter-individual variability in transgene expression was observed amongst the different transgenic lines, where gene constructs containing citrus-derived promoters were used. In silico analysis of the citrus-derived promoter sequences revealed that their activity may be controlled by several putative cis-regulatory elements. These citrus promoters will expand the availability of regulatory sequences for driving gene expression in citrus gene-modification programs.

Sweet orange genetic transformation with the attacin A gene under the control of phloem-specific promoters and inoculation with Candidatus Liberibacter asiaticus

ABSTRACT An alternative approach to control Huanglongbing disease in Citrus is the development of transgenic plants expressing genes that may influence pathogen development. We report herein the production of sweet orange transgenic plants bearing gene constructs containing the antimicrobial gene attacin A (attA) under the control of phloem-specific promoters. Transcripts of the attA gene were accumulated in the transgenic lines bearing the three gene constructs. However, phloem protein 2 promoters drive higher levels of attA mRNA than sucrose transporter 2 promoter. Candidatus Liberibacter asiaticus (CLas) were transmitted to transgenic plants via infected Asian citrus psyllid or by grafting infected budwood. The efficiency of CLas transmission via infected psyllids was very low and therefore did not allow evaluating the influence of attA expression on bacteria multiplication. On the other hand, CLas transmission via grafting infected budwood was very efficient. Huanglongbing (HLB) symptoms were detected five months after inoculation in both transgenic and non-transgenic inoculated plants. CLas titers, determined 12 months after inoculation, were similar in both transgenic and non-transgenic inoculated plants. However, non-transgenic inoculated plants showed a significant reduction in shoot development comparing to transgenic inoculated plants indicating that the expression of attA gene may influence the plant tolerance to HLB disease.