Electrophoretical studies of proteins of the hypopharyngeal glands and of the larval food of Melipona quadrifasciata anthidioides Lep (Hymenoptera, Meliponinae)

The electrophoretical protein patterns of hypopharyngeal glands, larval food of Melipona, and royal jelly of Apis were compared.Since protein patterns of hypopharyngeal glands from newly emerged workers, brood cell provisioners and foragers are similar to freshly deposited larval food, the identical protein bands probably represent actual gland secretion. This suggests that, as in Apis, the glands secrete proteins to the larval food, and maintain this ability throughout life, although at slightly different intensities, according to the activity of the bees.The similarity on the electrophoretic profiles of the major larval food protein in Apis and Melipona is an interesting finding because of its probable evolutionary significance.

Food restriction-induced myocardial dysfunction demonstrated by the combination of in vivo and in vitro studies

The aim of this study was to test the hypothesis that protein-calorie undernutrition decreases myocardial contractility jeopardizing ventricular function, and that ventricular dysfunction can be detected noninvasively. Five-month-old male Wistar-Kyoto rats were fed with regular rat chow ad libitum for 90 days (Control group, n = 14). A second group of rats received 50% of the amount of diet consumed by de control group (Food restricted group, n = 14). Global LV systolic function was evaluated in vivo, noninvasively, by transthoracic echocardiogram. After echocardiographic study, myocardial contractility was assessed in vitro in the isovolumetrically beating isolated heart in eight animals from each group (Langendorff preparation). The in vivo LV fractional shortening showed that food restriction depressed LV systolic function (p < 0.05). Myocardial contractility was impaired as assessed by the maximal rate of rise of LV pressure (+dP/dt), and developed pressure at diastolic pressure of 25 mmHg (p < 0.05). Furthermore, food restriction induced eccentric ventricular remodeling, and reduced myocardial elasticity and LV compliance (p < 0.05). In conclusion, food restriction causes systolic dysfunction probably due to myocardial contractility impairment and reduction of myocardial elasticity. © 2002 Elsevier B.V. All rights reserved.

Thermal and spectroscopic studies of the antioxidant food additive propyl gallate

Literature mentions propyl gallate (PG) as a non-toxic synthetic antioxidant that can be used as a food additive due to its high tolerance to heat. It is important to understand the thermal properties and to identify the decomposition products of this substance, since it has been reported to be thermally stable at temperatures as high as 300 °C. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry-photovisual (DSC-photovisual), coupled thermogravimetry-infrared spectroscopy (TG-FTIR) analyses and spectroscopic techniques were used to study the food additive PG. The TG-DTA curves, which were performed with the aid of DSC-photovisual, provided information concerning the thermal stability and decomposition profiles of the compound. From the TG-FTIR coupled techniques, it was possible to identify n-propanol as a possible volatile compound released during the thermal decomposition of the antioxidant. A complete spectroscopic characterization in the ultraviolet, visible, near and middle infrared regions was performed in order to understand the spectroscopic properties of PG.

Migration of Tinuvin P, a UV stabilizer, from PET bottles into fatty-food simulants

Tinuvin P migration from Polyethyleneterephthalate (PET) bottles was investigated using several fatty-food simulants such as olive oil, soybean oil, n-heptane and iso-octane, at exposure conditions of 2-10 days at 40 degrees C (total immersion). The stability of several UV stabilizers (BHT, Cyasorb UV 5411, Tinuvin P, Tinuvin 326 and Tinuvin 327) in n-heptane and iso-octane was also studied. After 10 days at 40 degrees C, losses of 6% and 20% in iso-octane and n-heptane respectively, were verified for Tinuvin P. Other UV stabilizers at the same experimental conditions showed higher losses (up to 30% for Tinuvin 327). These results confirm that, when carrying out specific migration studies, the stability of the substance of interest should be established in the food simulant to avoid underestimating the real migration behaviour. In order to quantify UV stabilizer migration, n-heptane and iso-octane solutions were concentrated and directly analysed by SIM mode GC-MS. For olive and soybean oils, Tinuvin P was isolated using size-exclusion chromatography and quantified by SIM mode GC-MS. Iso-octane proved to be a move suitable fatty-food simulant than n-heptane for the migration study of Tinuvin P from PET. Higher levels of Tinuvin P migrated to olive and soybean oils rather than to n-heptane. These results suggest that the MERCOSUL recommended official methods for specific migration studies should be revised since the migration levels using n-heptane as a fatty-food simulant could be underestimated when compared to edible oils. Copyright (C) 1999 John Wiley & Sons, Ltd.

Effect of Gamma Irradiation on Caprolactam Migration from Multi layer Polyamide 6 Films into Food Simulants: Development and Validation of a Gas Chromatographic Method

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Myocardial remodeling and dysfunction are induced by chronic food restriction in spontaneously hypertensive rats

Several studies have shown alterations in hearts from animals subjected to food restriction (FR). However, few experiments in hearts evaluating pressure overload have been reported. We examined the effects of chronic FR on myocardial function and morphology in spontaneously hypertensive rats (SHR). Sixty-day-old SHR were fed a control (C) or a restricted diet (daily intake reduced to 50% of amount of food consumed by the control group) for 90 days. Myocardial performance was studied in isolated left ventricular (LV) papillary muscle. Food restriction decreased body weight and LV weight; LV weight/body-weight ratio was lower in the food-restricted group (SHR-C, 2.84 +/- 0.21 mg/g; SHR-FR, 2.56 +/- 0.24 mg/g; P <.05). Food restriction did not change arterial systolic blood pressure. Myocyte surface area was lower in the food-restricted group (P <.01). Food restriction induced myocardial ultrastructural alterations including reduced sarcoplasm content, reduced and disorganized myofilaments, disorganized Z line, dilated sarcoplasmic reticulum, and deep infoldings of plasma membrane. Myocardial hydroxyproline concentration was increased in the restricted rats. Peak developed tension (P <.05) and maximum rate of tension development (P <.01) were decreased in the SHR-FR group. In conclusion, myocardium of SHR subjected to chronic FR presents attenuation of hypertrophy development, ultrastructural changes, increased collagen content, and systolic dysfunction. (c) 2006 Elsevier B.V. All rights reserved.

Food restriction promotes downregulation of myocardial L-type Ca2+ channels

Food restriction (FR) has been shown to impair myocardial performance. However, the mechanisms behind these changes in myocardial function due to FR remain unknown. Since myocardial L-type Ca2+ channels may contribute to the cardiac dysfunction, we examined the influence of FR on L-type Ca2+ channels. Male 60-day-old Wistar rats were fed a control or a restricted diet (daily intake reduced to 50% of the amount of food consumed by the control group) for 90 days. Myocardial performance was evaluated in isolated left ventricular papillary muscles. The function of myocardial L-type Ca2+ channels was determined by using a pharmacological Ca2+ channel blocker, and changes in the number of channels were evaluated by mRNA and protein expression. FR decreased final body weights, as well as weights of the left and right ventricles. The Ca2+ channel blocker diltiazem promoted a higher blockade on developed tension in FR groups than in controls. The protein content of L-type Ca2+ channels was significantly diminished in FR rats, whereas the mRNA expression was similar between groups. These results suggest that the myocardial dysfunction observed in previous studies with FR animals could be caused by downregulation of L-type Ca2+ channels.

Severe food restriction induces myocardial dysfunction related to SERCA2 activity

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

Can seasonal differences influence food web structure on preserved habitats? Responses from two Brazilian streams

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

Friction losses in valves and fittings for liquid food products

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

Kinetic studies of urban solid residues and leachate from sanitary landfill

Urban solid residues are constituted of food remaining, grass leaves, fruit peelings, paper, cardboard, rubber, plastic, etc. The organic fraction formed represents about 50% during the decomposition yields biogas and leachate, which are sources of pollution. Residue samples were collected from the landfill in different and cells from several ages and the corresponding leachate, both after treatments, were submitted to thermal analysis. Kinetic parameters were determined using Flynn-Wall-Ozawa method. The linear relation between the two kinetic parameters (ln A and E) was verified for organic residue urban's samples, but not for leachate's sample. The occurred difference can be attributed to the constituents present in leachate.

Chemical and Antidiarrheal Studies of Plinia cauliflora

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

Ovarian development in Meliponine bees (Hymenoptera: Apidae): the effect of queen presence and food on worker ovary development and egg production

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

Immunoassays for pesticide analysis in environmental and food matrices

Immunochemical methods have increased considerably in the past years, and many examples of small and large scale studies have demonstrated the reliability of the immunotechniques for control and monitoring gf contaminant residues in different kinds of samples. Application of the immunoassay (IA) methods in pesticide residue control is an area with enormous potential for growth. The most extensively studied IA is the enzyme-linked absorbent assay (ELISA), but several other approaches, that include radioimmunoassay and immunoaffinity chromatography, have been also developed recently. In comparison with classical analytical methods, IA methods offer the possibility of highly sensitive, relatively vapid, and cost-effective measurements. This paper introduces the general IAs used until now, focusing on their use in pesticide analysis, and discussing briefly the effects of interferences from solvent residues or matrix components on the IA performance. Numerous immunochemical methods commonly used for pesticide determination in different samples such as food, crop and environmental samples are presented.

Analysis of pesticides in food and environmental samples by enzyme-linked immunosorbent assays

Enzyme-linked immunosorbent assays (ELISAs) are the most extensively studied types of immunoassay and their application in pesticide residue monitoring is an area with enormous potential for growth. In comparison with classical analytical methods, ELISA methods offer the possibility of highly sensitive, relatively rapid, and cost-effective measurements. This review introduces the general ELISA formats used, focusing on their use in pesticide analysis. Identifying and studying the effects of interferences in immunoassays is an active area of research and we discuss the matrix effects observed in several studies involving e.g. food, crop and environmental samples. The procedures to eliminate the matrix interferences are briefly discussed. (C) 1998 Elsevier B.V. B.V.