RESUMO

The literature reports the presence of multiresistant microorganisms in wastewater discharged from municipal and hospital wastewater treatment plants (WWTPs). This has led to questions concerning the disinfection efficiency of the treatments applied. Thus, this study aimed to assess the efficiency of different chemical oxidation methods to disinfect and to degrade bacterial plasmids present in hospital wastewaters, to avoid the dispersion of antibiotic resistance genes in the environment. The methods tested were UV254nm alone or associated with an Ag or Ti-photocatalyst in photo-peroxonization (UV254 nm/H2O2/O3/Ag2O/Ag2CO3@PU or UV254 nm/H2O2/O3/TiO2@PU) under different pH conditions (4, 7, and 10). The application of plasmid DNA electrophoresis to hospital wastewater treated using an advanced oxidation process (AOP) achieved the total structural denaturation of microorganism plasmids at the three pH values tested. Also, UV254 nm alone was partially efficient in the disinfection of hospital wastewater. AOPs performed with the two functionalized catalysts resulted in 100% disinfection after 10 min at the three pH values tested. No intact plasmids were observed after 20 min of treatment with photocatalysis. This study could contribute to the development and improvement of wastewater treatment aimed at mitigating the spread of multiresistant microorganisms in the environment.

Assuntos

RESUMO

Agribusiness has a great relevance in the world׳s economy. It generates a considerable impact in the gross national product of several nations. Hence, it is the major driver of many national economies. Nowadays, from each new planting to harvesting process it is mandatory and crucial to apply some kind of technology to optimize a given singular process, or even the entire cropping chain. For instance, digital image analysis joined with machine learning methods can be applied to obtain and guarantee a higher quality of the harvest, leading to not only a greater profit for producers, but also better products with lower cost to the final consumers. Thus, to provide this possibility this work describes a visual feature dataset from soybean seed images obtained from the tetrazolium test. This is a test capable to define how healthy a given seed is (e.g. how much the plant will produce, or if it is resistant to inclement weather, among others). To answer these questions we proposed this dataset which is the cornerstone to provide an effective classification of the soybean seed vigor (i.e. an extremely tiresome human visual inspection process). Besides, as one of the most prominent international commodity, the soybean production must follow rigid quality control process to be part of world trade. Hence, small mistakes in the seed vigor definition of a given seed lot can lead to huge losses.

RESUMO

BACKGROUND: The increasing prevalence of antibiotic resistant bacteria has raised an urgent need for substitute remedies. Antimicrobial peptides (AMPs) are considered promising candidates to address infections by multidrug-resistant bacteria through new mechanisms of action that require a careful evaluation of their performance. OBJECTIVE: Identification of effective AMPs against Neisseria meningitidis, which represents a pathogen of great public health importance worldwide that is intrinsically resistant to some AMPs, such as polymyxin B. METHODS: A cationic 11-residue peptide (KLKLLLLLKLK), referred to as poly-Leu, was synthesized and its antimeningococcal activity was compared to cecropin A and poly-P (KLKPPPPPKLK) through a variety of assays. Flow cytometry was used to measure propidium iodide uptake by N. meningitidis serotype B as an indicator of the effectiveness of each peptide when added to cultures at different concentrations. RESULTS: The addition of the poly-Leu peptide led to a 90.3% uptake of the dye with an EC50 value of 7.9 µg mL-1. In contrast, uptake was <10% in cells grown in the absence of peptides or with an identical concentration of cecropin and poly-Pro peptides. Electron micrographs indicated that the integrity of the cellular wall and internal membrane was impacted in relation to peptide concentrations, which was confirmed by the detection of released alkaline phosphatase from the periplasmic space due to disruption of the external membrane. CONCLUSION: Poly-Leu peptide demonstrated definitive antimicrobial activity against N. meningitidis.

Assuntos

RESUMO

Tropical diseases caused by parasitic infections continue to cause socioeconomic distress worldwide. Among these, Chagas disease has become a great concern because of globalization. Caused by Trypanosoma cruzi, there is an increasing need to discover new, more effective methods to manage infections that minimize disease onset. Antimicrobial peptides represent a possible solution to this challenge. As effector molecules of the innate immune response against pathogens, they are the first line of defense found in all multi-cellular organisms. In amphibians, temporins are a large family of antimicrobial peptides found in skin secretions. Their functional roles and modes of action present unique properties that indicate possible candidates for therapeutic applications. Here, we investigated the trypanocide activity of temporizin and temporizin-1. Temporizin is an artificial, hybrid peptide containing the N-terminal region of temporin A, the pore-forming region of gramicidin and a C-terminus consisting of alternating leucine and lysine. Temporizin-1 is a modification of temporizin with a reduction in the region responsible for insertion into membranes. Their activities were evaluated in a cell permeabilization assay by flow cytometry, an LDH release assay, electron microscopy, an MTT assay and patch clamp experiments. Both temporizin and temporizin-1 demonstrated toxicity against T. cruzi with temporizin displaying slightly more potency. At concentrations up to 100 µg/ ml, both peptides exhibited low toxicity in J774 cells, a macrophage lineage cell line, and no toxicity was observed in mouse primary peritoneal macrophages. In contrast, the peptides showed some toxicity in rat adenoma GH3 cells and Jurkat human lymphoma cells with temporizin-1 displaying lower toxicity. In summary, a shortened form of the hybrid temporizin peptide, temporizin-1, was efficient at killing T. cruzi and it has low toxicity in wild-type mammalian cells. These data suggest that temporizin-1 might be a candidate for Chagas disease therapy.

Assuntos

RESUMO

Hospital wastewater treatments must ensure that all genetic material is destroyed, since nuclear and extra-nuclear DNA can show antimicrobial resistance and contain recombinant genes, which promote vertical and/or horizontal gene transfer, amplifying the current problem of the emergence of antibiotic-resistant microorganisms. In this study, we investigated whether ozonolysis or ozonolysis/sonolysis in combination can denature genetic material, i.e., destroy the integrity of DNA molecules, present in hospital wastewaters. To achieve this goal, hospital wastewaters were treated by ozonolysis or ozonolysis/sonolysis in combination (at 70 and 100 W L(-1)) and both raw and treated wastewaters were analyzed in terms of disinfection and DNA denaturation efficiency quantified by viable cell counts and by agarose gel electrophoresis. In the ozonolysis treatment, the agarose gel electrophoresis technique showed that the ozone-treated samples contained DNA molecules, while combined ozonolysis/sonolysis destroyed the DNA in a power density-dependent manner (64% at 70 W L(-1) and 81% at 100 W L(-1)). Care must be taken by environmental managers to distinguish disinfection processes from DNA denaturation processes, since these two terms are not synonymous.

Assuntos

RESUMO

Antibiotics are widely used for the treatment of dairy cows and the residues of these drugs may remain in milk and dairy products, which can be a potential threat to human health. Exposure to low levels of antibiotics is considered a public health problem as this may result in the development of resistant strains of human bacteria. The presence of antibiotic residues (AR) in milk is also a problem for the dairy industry as they can inhibit the growth of lactic bacteria. According to Brazilian legislation, antimicrobials should be used in accordance with Good Farming Practices. However, recent studies have reported contamination in milk marketed in the country. This work aimed to review studies, published over the last 10 years, which describe AR in milk marketed in Brazil. The Maximum Residue Limit, the methods for quantification of AR and the results of published studies by authors and government agencies are discussed.

Los antibióticos se utilizan ampliamente para el tratamiento de las vacas lecheras y los residuos de estos medicamentos pueden permanecer en la leche y los productos lácteos, los que pueden ser una amenaza potencial para la salud humana. La exposición a bajos niveles de antibióticos se considera un problema de salud pública ya que pueden resultar en el desarrollo de cepas resistentes de bacterias humanos. De acuerdo con la legislación brasileña, los antimicrobianos deben ser utilizados de acuerdo con las Buenas Prácticas Agrícolas. Sin embargo, estudios recientes han informado de la contaminación de la leche comercializada en el país. Este trabajo tuvo como objetivo revisar los estudios publicados en los últimos 10 años, que describen residuos de antimicrobianos en la leche comercializada en Brasil. Se discuten los límites máximos de residuos, los métodos para la cuantificación y los resultados de los estudios publicados por autores y agencias gubernamentales.

Assuntos

RESUMO

Reestablishing feelings of control after experiencing uncertainty has long been considered a fundamental motive for human behavior. We propose that rituals (i.e., socially stipulated, causally opaque practices) provide a means for coping with the aversive feelings associated with randomness due to the perception of a connection between ritual action and a desired outcome. Two experiments were conducted (one in Brazil [n = 40] and another in the United States [n = 94]) to evaluate how the perceived efficacy of rituals is affected by feelings of randomness. In a between-subjects design, the Scramble Sentence Task was used as a priming procedure in three conditions (i.e., randomness, negativity, and neutral) and participants were then asked to rate the efficacy of rituals used for problem-solving purposes. The results demonstrate that priming randomness increased participants' perception of ritual efficacy relative to negativity and neutral conditions. Implications for increasing our understanding of the relationship between perceived control and ritualistic behavior are discussed.

Assuntos

RESUMO

The aim of this work was to investigate whether an alkaline ecto-phosphatase activity is present in the surface of Trypanosoma rangeli. Intact short epimastigote forms were assayed for ecto-phosphatase activity to study kinetics and modulators using ß-glycerophosphate (ß-GP) and p-nitrophenyl phosphate (pNPP) as substrates. Its role in parasite development and differentiation was also studied. Competition assays using different proportions of ß-GP and pNPP evidenced the existence of independent and non-interacting alkaline and acid phosphatases. Hydrolysis of ß-GP increased progressively with pH, whereas the opposite was evident using pNPP. The alkaline enzyme was inhibited by levamisole in a non-competitive fashion. The Ca(2+) present in the reaction medium was enough for full activity. Pretreatment with PI-PLC decreased the alkaline but not the acid phosphatase evidence that the former is catalyzed by a GPI-anchored enzyme, with potential intracellular signaling ability. ß-GP supported the growth and differentiation of T. rangeli to the same extent as high orthophosphate (Pi). Levamisole at the IC50 spared significantly parasite growth when ß-GP was the sole source of Pi and stopped it in the absence of ß-GP, indicating that the alkaline enzyme can utilize phosphate monoesters present in serum. These results demonstrate the existence of an alkaline ecto-phosphatase in T. rangeli with selective requirements and sensitivity to inhibitors that participates in key metabolic processes in the parasite life cycle.

Assuntos

RESUMO

An analysis of a series of five peptides composed of various portions of the pleurocidin (Plc) sequence identified a l2-amino acid fragment from the C-terminus of Plc, designated Plc-2, as the smallest fragment that retained a antimicrobial activity comparable to that of the parent compound. MIC tests in vitro with low-ionic-strength medium showed that Plc-2 has potent activity against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus but not against Enterococcus faecalis. The antifungal activity of the synthetic peptides against phytopathogenic fungi, such as Fusarium oxysporum, Colletotrichum sp., Aspergillus niger and Alternaria sp., also identified Plc-2 as a biologically active peptide. Microscopy studies of fluorescently stained fungi treated with Plc-2 demonstrated that cytoplasmic and nuclear membranes were compromised in all strains of phytopathogenic fungi tested. Together, these results identify Plc-2 as a potential antimicrobial agent with similar properties to its parent compound, pleurocidin. In addition, it demonstrated that the KHVGKAALTHYL residues are critical for the antimicrobial activity described for pleurocidin.

Assuntos

RESUMO

Rituals pose a cognitive paradox: although widely used to treat problems, rituals are causally opaque (i.e., they lack a causal explanation for their effects). How is the efficacy of ritual action evaluated in the absence of causal information? To examine this question using ecologically valid content, three studies (N=162) were conducted in Brazil, a cultural context in which rituals called simpatias are used to treat a great variety of problems ranging from asthma to infidelity. Using content from existing simpatias, experimental simpatias were designed to manipulate the kinds of information that influences perceptions of efficacy. A fourth study (N=68) with identical stimuli was conducted with a US sample to assess the generalizability of the findings across two different cultural contexts. The results provide evidence that information reflecting intuitive causal principles (i.e., repetition of procedures, number of procedural steps) and transcendental influence (i.e., presence of religious icons) affects how people evaluate ritual efficacy.

Assuntos

RESUMO

The pathway of electron transport to nitrogenase in the endophytic beta-Proteobacterium Herbaspirillum seropedicae has not been characterized. We have generated mutants in two nif-associated genes encoding putative ferredoxins, fdxA and fdxN. The fdxA gene is part of the operon nifHDKENXorf1orf2fdxAnifQmodABC and is transcribed from the nifH promoter, as revealed by lacZ gene fusion. The fdxN gene is probably cotranscribed with the nifB gene. Mutational analysis suggests that the FdxA protein is essential for maximum nitrogenase activity, since the nitrogenase activity of the fdxA mutant strain was reduced to about 30% of that of the wild-type strain. In addition, the fdxA mutation had no effect on the nitrogenase switch-off in response to ammonium. Nitrogenase activity of a mutant strain lacking the fdxN gene was completely abolished. This phenotype was reverted by complementation with fdxN expressed under lacZ promoter control. The results suggest that the products of both the fdxA and fdxN genes are probably involved in electron transfer during nitrogen fixation.

Assuntos

RESUMO

In this work, we showed that living cells of Trypanosoma rangeli express different ecto-phosphatase activities in response to different inorganic phosphate (Pi) concentrations in the culture medium. The ecto-phosphatase activity from T. rangeli grown at low-Pi concentration was inhibited by the increase of the pH, while the ecto-phosphatase of the cells grown at high Pi concentration was not modulated by the change of the pH of the medium. Okadaic acid inhibited only the ecto-phosphatase activity from cells grown at low-Pi concentration but not the ecto-phosphatase activity from cells grown at high-Pi concentration. Accordingly, phosphatase activity from T. rangeli grown at low Pi concentration was able to hydrolyze P-serine and P-threonine at high rate but not P-tyrosine. The phosphatase activity from T. rangeli grown at high-Pi concentration was able to hydrolyze P-serine, P-threonine and P-tyrosine with the same rate. The addition of anterior midgut homogenate of Rhodnius prolixus on the epimastigotes suspension inhibited the enzyme activity of T. rangeli grown at low-Pi concentration. On the other hand, anterior midgut homogenate had no effect in the ecto-phosphatase of T. rangeli maintained at high-Pi concentration. Altogether, the results described here indicate that ecto-phosphatase activities hydrolyzing phosphorylated compounds present in the extracellular medium of T. rangeli are regulated by the external Pi concentration.

Assuntos

RESUMO

Here we demonstrate for the first time that growth of Trypanosoma rangeli, a protozoa parasite, is strongly dependent on the presence of inorganic phosphate (Pi) in the culture medium and that the replacement of the inorganic phosphate in the culture medium by beta-glycerophosphate, a substrate for phosphatases lead the cells to achieve its maximal growth. The ecto-phosphatase activity present on the external surface of T. rangeli decreased during the growth phase of the parasite, suggesting that this enzyme could be important for the development. Accordingly, the inhibition of this ecto-phosphatase activity by sodium orthovanadate also inhibited the proliferation of T. rangeli. Parasites maintained in a Pi-starved culture medium (2 mM Pi) had 4-fold more ecto-phosphatase activity as compared to parasites maintained in a Pi-supplemented culture medium (50 mM Pi). Altogether, these results presented here suggest that this ecto-phosphatase activity leads to hydrolysis of phosphorylated compounds present in the extracellular medium, which could contribute to the acquisition of inorganic phosphate during the development of T. rangeli epimastigotes.

Assuntos

RESUMO

We report an investigation for 16 bacteria and viruses among 184 children hospitalized with pneumonia in Salvador, Brazil. Etiology was established in 144 (78%) cases. Viral, bacterial, and mixed infections were found in 110 (60%), 77 (42%), and 52 (28%) patients, respectively. Rhinovirus (21%) and Streptococcus pneumoniae (21%) were the most common pathogens. Our results demonstrate the importance of viral and pneumococcal infections among those patients.

Assuntos

RESUMO

In this work, we characterized a Mg(2+)-dependent ecto-phosphatase activity present in live Trypanosoma rangeli epimastigotes. This enzyme showed capacity to hydrolyze the artificial substrate for phosphatases, p-nitrophenylphosphate (p-NPP). At saturating concentration of p-NPP, half-maximal p-NPP hydrolysis was obtained with 0.23mM Mg(2+). Ca(2+) had no effect on the basal phosphatase activity, could not substitute Mg(2+) as an activator and in contrast inhibited the p-NPP hydrolysis stimulated by Mg(2+). The dependence on p-NPP concentration showed a normal Michaelis-Menten kinetics for this phosphatase activity with values of V(max) of 8.94+/-0.36 nmol p-NP x h(-1) x 10(-7) cells and apparent K(m) of 1.04+/-0.16 mM p-NPP. Mg(2+)-dependent ecto-phosphatase activity was stimulated by the alkaline pH range. Experiments using inhibitors, such as, sodium fluoride, sodium orthovanadate and ammonium molybdate, inhibited the Mg(2+)-dependent ecto-phosphatase activity. Inorganic phosphate (Pi), a product of phosphatases, inhibited reversibly in 50% this activity. Okadaic acid and microcystin-LR, specific phosphoserine/threonine phosphatase inhibitors, inhibited significantly the Mg(2+)-dependent ecto-phosphatase activity. In addition, this phosphatase activity was able to recognize as substrates only o-phosphoserine and o-phosphothreonine, while o-phosphotyrosine was not a good substrate for this phosphatase. Epimastigote forms of T. rangeli exhibit a typical growth curve, achieving the stationary phase around fifth or sixth day and the Mg(2+)-dependent ecto-phosphatase activity decreased around 10-fold with the cell growth progression. Cells maintained at Pi-deprived medium (2 mM Pi) present Mg(2+)-dependent ecto-phosphatase activity approximately threefold higher than that maintained at Pi-supplemented medium (50 mM Pi).

Assuntos

RESUMO

The salivary glands of insect's vectors are target organs to study the vectors-pathogens interactions. Rhodnius prolixus an important vector of Trypanosoma cruzi can also transmit Trypanosoma rangeli by bite. In the present study we have investigated ecto-phosphatase activity on the surface of R. prolixus salivary glands. Ecto-phosphatases are able to hydrolyze phosphorylated substrates in the extracellular medium. We characterized these ecto-enzyme activities on the salivary glands external surface and employed it to investigate R. prolixus-T. rangeli interaction. Salivary glands present a low level of hydrolytic activity (4.30+/-0.35 nmol p-nitrophenol (p-NP)xh(-1)xgland pair(-1)). The salivary glands ecto-phosphatase activity was not affected by pH variation; and it was insensitive to alkaline inhibitor levamisole and inhibited approximately 50% by inorganic phosphate (Pi). MgCl2, CaCl2 and SrCl2 enhanced significantly the ecto-phosphatase activity detected on the surface of salivary glands. The ecto-phosphatase from salivary glands surface efficiently releases phosphate groups from different phosphorylated amino acids, giving a higher rate of phosphate release when phospho-tyrosine is used as a substrate. This ecto-phosphatase activity was inhibited by carbohydrates as d-galactose and d-mannose. Living short epimastigotes of T. rangeli inhibited salivary glands ecto-phosphatase activity at 75%, while boiled parasites did not. Living long epimastigote forms induced a lower, but significant inhibitory effect on the salivary glands phosphatase activity. Interestingly, boiled long epimastigote forms did not loose the ability to modulate salivary glands phosphatase activity. Taken together, these data suggest a possible role for ecto-phosphatase on the R. prolixus salivary glands-T. rangeli interaction.

Assuntos

RESUMO

In prokaryotes molybdenum is taken up by a high-affinity ABC-type transporter system encoded by the modABC genes. The endophyte â-Proteobacterium Herbaspirillum seropedicae has two modABC gene clusters and two genes encoding putative Mo-dependent regulator proteins (ModE1 and ModE2). Analysis of the amino acid sequence of the ModE1 protein of H. seropedicae revealed the presence of an N-terminal domain containing a DNA-binding helix-turn-helix motif (HTH) and a C-terminal domain with a molybdate-binding motif. The second putative regulator protein, ModE2, contains only the helix-turn-helix motif, similar to that observed in some sequenced genomes. We cloned the modE1 (810 bp) and modE2 (372 bp) genes and expressed them in Escherichia coli as His-tagged fusion proteins, which we subsequently purified. The over-expressed recombinant His-ModE1 was insoluble and was purified after solubilization with urea and then on-column refolded during affinity chromatography. The His-ModE2 was expressed as a soluble protein and purified by affinity chromatography. These purified proteins were analyzed by DNA band-shift assays using the modA2 promoter region as probe. Our results indicate that His-ModE1 and His-ModE2 are able to bind to the modA2 promoter region, suggesting that both proteins may play a role in the regulation of molybdenum uptake and metabolism in H. seropedicae.

RESUMO

We describe cell therapy for severe ischemic heart failure using transendocardial injection of autologous bone-marrow-derived mononuclear cells. The treated patients had significantly less heart failure and angina, sustained significant improvement of pumping power, exercise capacity, cardiac muscle irrigation, and blood supply to the body. Electrical and mechanical mappings of the myocardium before and after the therapy, and anatomopathological examination of the myocardium of one of the patients that had deceased of a stroke eleven months after the treatment indicated sustained neoangiogenesis and improvement of activity and quantity of cardiomyocytes in the injected regions. Post-hoc analyses of injected cell phenotype and improvement of myocardial function indicate that presence of CD8+ and CD56+ cells does not correlate with good prognostics, suggesting a possibility of cell selection. For 'no-option' severe cardiac patients, significant benefits of cell therapy and absence of adverse effects may justify the application of bone-marrow-derived cell therapy.

Assuntos

RESUMO

Trypanosoma rangeli is a parasite of a numerous wild and domestic animals, presenting wide geographical distribution and high immunological cross-reactivity with Trypanosoma cruzi, which may lead to misdiagnosis. T. rangeli has a complex life cycle, involving distinct morphological and functional forms in the vector. Here, we characterized the cell surface polypeptides and the phosphatase activities in short and long epimastigotes forms of T. rangeli, using intact living parasites. The surface protein profile revealed by the incubation of parasites with biotin showed a preferential expression of the 97, 70, 50, 45, 25-22, and 15 kDa biotinylated polypeptides in the long forms, in contrast to the 55 and 28 kDa biotinylated polypeptides synthesized by the short epimastigotes. Additionally, flow cytometry analysis showed that the short forms had relatively lower biotin surface binding than long ones. The involvement of phosphatases with the trypanosomatid differentiation has been proposed. In this sense, T. rangeli living parasites were able to hydrolyze the artificial substrate p-nitrophenylphosphate at a rate of 25.57+/-2.03 and 10.09+/-0.93 nmol p-NPP x h(-1) x 10(7) cells for the short and long epimastigotes, respectively. These phosphatase activities were linear with time for at least 60 min and the optimum pH lies in the acid range. Classical inhibitors of acid phosphatases, such as ammonium molybdate, sodium fluoride, and zinc chloride, showed a significant decrease in these phosphatase activities, with different patterns of inhibition. Additionally, these phosphatase activities presented different kinetic parameters (Km and Vmax) and distinct sensitivities to divalent cations. Both epimastigotes were unable to release phosphatase to the extracellular environment. Cytochemical analysis demonstrated the localization of these enzymes on the parasite surfaces (cell body and flagellum) and in intracellular vacuoles, resembling acidocalcisomes.

Assuntos

RESUMO

OBJECTIVE: This study aimed at assessing the effects of autologous transendocardial transplantation of bone marrow mononuclear cells (ATTBMMC) on symptoms, exercise capacity, myocardial perfusion and contractility in patients with severe ischemic heart disease during a 6-month follow-up period. METHODS: This prospective study comprised 21 patients as follows: the first 14 patients forming the treated group, and the last 7 patients forming the control group. Initially, all patients underwent clinical and laboratory assessment, treadmill testing, echocardiography, myocardial scintigraphy, and 24-hour Holter. The bone marrow mononuclear cells (BMMC) were isolated, washed, and diluted in 0.9% saline solution for transendocardial injection in areas of viable myocardium in the treated group, (15 0.2-mL injections). All patients were reassessed in the end of 2 and 6 months of follow-up. RESULTS: The demographic data and other characteristics did not significantly differ between the groups in the initial evaluation. No major adverse events related to the ATTBMMC were observed. In the end of 6 months, a reduction in the ischemic area was observed on nuclear perfusion imaging (P=0.05), as was a significant improvement in symptoms, functional capacity, and left ventricular overall function. CONCLUSION: This study showed that transendocardial injections of BMMC are safe in human beings with ischemic heart disease associated with severe ventricular dysfunction. The effects observed in the short run were maintained up to the sixth month of follow-up.

Assuntos