Bruna Mara Aparecida de Carvalho

Antitumoral activity of snake venom proteins: new trends in cancer therapy

For more than half a century, cytotoxic agents have been investigated as a possible treatment for cancer. Research on animal venoms has revealed their high toxicity on tissues and cell cultures, both normal and tumoral. Snake venoms show the highest cytotoxic potential, since ophidian accidents cause a large amount of tissue damage, suggesting a promising utilization of these venoms or their components as antitumoral agents. Over the last few years, we have studied the effects of snake venoms and their isolated enzymes on tumor cell cultures. Some in vivo assays showed antineoplastic activity against induced tumors in mice. In human beings, both the crude venom and isolated enzymes revealed antitumor activities in preliminary assays, with measurable clinical responses in the advanced treatment phase. These enzymes include metalloproteases (MP), disintegrins, L-amino acid oxidases (LAAOs), C-type lectins, and phospholipases A2 (PLA2s). Their mechanisms of action include direct toxic action (PLA2s), free radical generation (LAAOs), apoptosis induction (PLA2s, MP, and LAAOs), and antiangiogenesis (disintegrins and lectins). Higher cytotoxic and cytostatic activities upon tumor cells than normal cells suggest the possibility for clinical applications. Further studies should be conducted to ensure the efficacy and safety of different snake venom compounds for cancer drug development.

Snake Venom PLA2s Inhibitors Isolated from Brazilian Plants: Synthetic and Natural Molecules

Ophidian envenomation is an important health problem in Brazil and other South American countries. In folk medicine, especially in developing countries, several vegetal species are employed for the treatment of snakebites in communities that lack prompt access to serum therapy. However, the identification and characterization of the effects of several new plants or their isolated compounds, which are able to inhibit the activities of snake venom, are extremely important and such studies are imperative. Snake venom contains several organic and inorganic compounds; phospholipases A2 (PLA2s) are one of the principal toxic components of venom. PLA2s display a wide variety of pharmacological activities, such as neurotoxicity, myotoxicity, cardiotoxicity, anticoagulant, hemorrhagic, and edema-inducing effects. PLA2 inhibition is of pharmacological and therapeutic interests as these enzymes are involved in several inflammatory diseases. This review describes the results of several studies of plant extracts and their isolated active principles, when used against crude snake venoms or their toxic fractions. Isolated inhibitors, such as steroids, terpenoids, and phenolic compounds, are able to inhibit PLA2s from different snake venoms. The design of specific inhibitors of PLA2s might help in the development of new pharmaceutical drugs, more specific antivenom, or even as alternative approaches for treating snakebites.

Cryogel Poly(acrylamide): Synthesis, Structure and Applications

This review focuses on the description of macromolecular gels formed as a result of polymerization, under freezing conditions, from monomer solutions. Materials resulting from this polymerization are known as cryogels and have particular properties, such as porosity of a specific nature. They are attractive in terms of biotechnological applications. The cryogels have interconnected macropores, and their preparation method from aqueous solutions in freezing conditions is a process that combines the crystallization of a solvent with the copolymerization of monomers. Cryogels have recently been used as adsorbents for the efficient separation and purification of biomacromolecules, such as proteins, DNA, cell organelles, viruses and enzymes that are present in solutions. Despite the wide application of cryogels, improvements in their preparation are necessary to minimize problems, such as the formation of hydrogels, instead of cryogels. Hydrogels form due to immediate polymerization after addition of the redox initiator before solvent freezing. The synthesis and use of cryogels as chromatographic supports are also discussed.

Rapid detection of whey in milk powder samples by spectrophotometric and multivariate calibration

A rapid method for the detection and quantification of the adulteration of milk powder by the addition of whey was assessed by measuring glycomacropeptide protein using mid-infrared spectroscopy (MIR). Fluid milk samples were dried and then spiked with different concentrations of GMP and whey. Calibration models were developed using multivariate techniques, from spectral data. For the principal component analysis and discriminant analysis, excellent percentages of correct classification were achieved in accordance with the increase in the proportion of whey samples. For partial least squares regression analysis, the correlation coefficient (r) and root mean square error of prediction (RMSEP) in the best model were 0.9885 and 1.17, respectively. The rapid analysis, low cost monitoring and high throughput number of samples tested per unit time indicate that MIR spectroscopy may hold potential as a rapid and reliable method for detecting milk powder frauds using cheese whey.

Direct capture of lactoferrin from cheese whey on supermacroporous column of polyacrylamide cryogel with copper ions

Lactoferrin is a protein that is present in cheese whey (a waste product from the dairy industry) and has several biological activities. However, its production from whey must have a high yield and low cost for industrial applications. As such, this study reports the use of polyacrylamide cryogel, loaded with Cu(2+) (through the bond with iminodiacetic acid (IDA)), as an adsorbent for the chromatographic process to capture lactoferrin whey. Ultrafiltered cheese whey was passed through the cryogel-IDA-Cu(2+) system. The eluates were subjected to analysis of total protein, SDS-PAGE and size exclusion chromatography. The results showed an axial dispersion coefficients, at different superficial velocities of liquid, in a range of 10(-6)-10(-5)m(2)/s. The cryogel demonstrated good hydraulic permeability (4.7086×10(-13)m(2)) and a porosity of approximately 78.2%. The IDA-Cu(2+) cryogel system was also able to capture lactoferrin in high purity.

Fracionamento de carboidratos de silagem de capim-elefante emurchecido ou com farelo de cacau

The experiment was carried out to determine the carbohydrate fractions of elephantgrass silage wilted under the sun for eight hours. Other treatments included the same elephantgrass without wilting but with addition of 0, 7, 14, 21, and 28% of cocoa meal at the ensiling process. The PVC silos used in the experiment had 5.3 L of capacity, and they were opened 45 days after ensiling. The wilted treatment showed total carbohydrate (TC) concentration similar to treatments with 14 and 21% cocoa meal. The regression analysis detected linear reduction of this fraction with the addition of cocoa meal. For all carbohydrate estimated fractions, the wilted treatment showed similar values to the treatment without wilting. The silage TC fractions were altered by cocoa meal addictions, presenting high concentration of A+B1, and NDFi, and low concentration of B2 with increasing cocoa meal level.

Microcalorimetric study of the adsorption of lactoferrin in supermacroporous continuous cryogel with immobilized Cu2+ ions

The adsorption affinity of lactoferrin from whey in monolithic supermacroporous cryogel was analyzed using equilibrium data adsorptive isothermal titration microcalorimetry to measure thermodynamic information governing the process. Isotherm data was obtained at temperatures of 20, 30 and 40°C, pH 6, 7 and 8, and ionic strength of 200, 600 and 1000mmolL(-1) NaCl. The Langmuir model was fitted to equilibrium data. The binding was tighter at higher temperatures. The adsorption of protein was observed as spontaneous in all cases analyzed. The microcalorimetric study indicated that, in most cases examined, the adsorption of the protein in the matrix was entropy and enthalpy favored and entropy driven. Results provide data to enable the improvement of technical processes for the affinity separation of proteins.

Aspectos metodológicos do comportamento ingestivo de ovinos alimentados com capim-elefante amonizado e subprodutos agroindustriais

The objective of this trial was to compare and determine the most adequate time interval to register chewing activity in Santa Ines sheep. The following time intervals were investigated: 5, 10, 15, 20, 25, and 30 minutes. Eighteen intact male sheep averaging 22.62 kg of body weight at the beginning of the study were used. Animals were housed in individual pens and randomly assigned to one of six treatments: ammonia-treated elephantgrass or elephatgrass supplemented with three concentrates sources (0% cocoa meal and palm kernel cake, 40% cocoa meal, and 40% palm kernel cake partially replacing corn and soybean meal) in a forage:concentrate ratio of 60:40. Chewing activity (time spent eating, ruminanting, and idle) was measured during two 24 hours periods at the end of the experimental period. There was no significant difference in the time spent eating, ruminating and idle among the studied intervals. However, significant differences were observed for the number of meals, rumination, and idle activities as well as for the mean time spent at each of these individual activities. It can be concluded that time spent eating, ruminating, and idle can be measured at every 30 minutes interval in Santa Ines sheep while five minutes interval was required to register the number and the mean time spent at each chewing activity.

Silagem de resíduo de peixes em dietas para alevinos de tilápia-do-nilo

The trial was conducted to evaluate the effects of feeding increasing levels (0, 10, 20 and 30%) of fish residues silage on the chemical composition of this silage with 30% wheat meal and on the performance of tilapia Nile fingerlings. Nile tilapia filleting residues were handle chopped, grounded and heated during 15 minutes at 105°C. After this procedure, it was added 30% wheat meal relative to residue total weight. The material was stored in plastic silos with 20 liters capacity during 30 days. Contents of DM, CP, EE, ash, calcium, P, pH and ammonia nitrogen were determined. The effects of fish residues silage on length, height, weight gain, apparent feed conversion, protein efficiency rate and survival means were evaluated. No significant difference of treatments on the evaluated parameters was observed. Residues of Nile tilapia filleting added of 30% wheat meal produce good quality silageto be used in fish feeding. The silage can be included up to 30% in the diets for tilapia fingerlings, with no effect on performance.

Vascular effects and electrolyte homeostasis of the natriuretic peptide isolated from Crotalus oreganus abyssus (North American Grand Canyon rattlesnake) venom

Crotalus oreganus abyssus is a rattlesnake that is usually found in the Grand Canyon, United States of America. Knowledge regarding the composition of C. o. abyssus venom is scarce. New natriuretic peptides (NPs) have been isolated and characterized from the venoms of members of the Crotalinae family. The NP family comprises three members, ANP (atrial natriuretic peptide), BNP (b-type natriuretic peptide) and CNP (c-type natriuretic peptide), and has an important role in blood pressure regulation and electrolyte homeostasis. The aim of the present study was to characterize a novel natriuretic-like peptide (Coa_NP2), isolated from C. o. abyssus venom. The Coa_NP2 presents an average molecular mass of 3419.88Da (theoretical average molecular mass 3418.94Da, monoisotopic molecular mass 3416.66Da and theoretical PI 7.78) and its amino acid sequence presents the loop region that is characteristic of natriuretic peptides. The peptide has 32 amino acids and its complete sequence is SYGISSGCFGLKLDRIGTMSGLGCWRLLQDSP. Coa_NP2 is a natriuretic peptide of the ANP/BNP-like family, since the carboxyterminal region of CNP has its own NP domain. We demonstrate, herein, that Coa_NP2 produces a dose-dependent decrease in mean arterial pressure in rats, followed by significant increases in concentrations of markers of nitric oxide formation measured in the plasma and vasorelaxation in a thoracic aortic ring bath. The structural and biological aspects confirm Coa_NP2 as a new natriuretic peptide, isolated from snake venom.