Detection of pathogenic Escherichia coli and microbiological quality of chilled shrimp sold in street markets.

UNLABELLED: Foodborne illnesses caused by Escherichia coli are one of the most important gastrointestinal diseases and therefore represent a public health risk. The presence of E. coli in water or in products such as shrimp indicates faecal contamination. However, indicator micro-organisms can be used to evaluate the microbiological quality of food sold in markets. This study focused on detecting isolates of E. coli containing the genes stx1A, stx2A, eae, LTI, STa, STb, aggR and pCVD432 in chilled shrimp sold in street markets in the municipality of São Paulo, Brazil, and to assess the microbiological quality of this product. Enteropathogenic and enterotoxigenic E. coli pathotypes were detected on the surface of two chilled shrimp samples. Salmonella spp. was not isolated. In addition, contamination of surface and muscle of the shrimp samples was found to be correlated. The detection of EPEC and ETEC pathotypes in chilled shrimp sold in street markets in Brazil provides useful epidemiological information for public health authorities to improve food safety and public health. SIGNIFICANCE AND IMPACT OF THE STUDY: Shrimps are crustaceans commonly produced and consumed in Brazil. Specimens of Farfantepenaeus brasiliensis and Litopenaeus schmitti sold in street markets were examined by PCR to detect the presence of Escherichia coli pathotypes (enteropathogenic, enterotoxigenic, enterohemorrhagic and enteroinvasive). EPEC and ETEC strains were detected in whole shrimp. These findings provide useful information for public health authorities to improve the food safety and health of the Brazilian population.

Shiga toxigenic and enteropathogenic Escherichia coli in water and fish from pay-to-fish ponds.

UNLABELLED: Escherichia coli is part of the normal microflora of the intestines of mammals. However, among the enteric pathogens, it is one of the leading causes of intestinal diseases, especially Shiga toxigenic E. coli, which can cause diarrhoea, haemorrhagic colitis and complications like haemolytic uraemic syndrome and thrombotic thrombocytopaenic purpura. Escherichia coli is considered a serious public health problem. Water and fish samples were subjected to biochemical tests to confirm the presence of E. coli and by PCR to verify the presence of pathogenic strains (O157, enteropathogenic and shiga toxigenic) in water and fish (skin, gastrointestinal tract and muscles) from pay-to-fish ponds located in the Córrego Rico watershed in the northeastern region of the state of São Paulo, Brazil. Of the 115 E. coli isolates from fish or water, five (4·34%) contained eae and stx2 genes, one had only the eae gene and two had the stx1 gene. An isolate containing the stx2 gene was also found in the water sample. In addition, eight isolates (6·95%) from the fish gastrointestinal tract contained rfbEO157:H7 (O157 gene), and three (2·61%) contained stx2 and eae genes, demonstrating the potential risk to the environment and public health. The results provide useful basic information for the proper management of these environments and animals in order to prevent faecal pollution, reducing health risks to the Brazilian population. SIGNIFICANCE AND IMPACT OF THE STUDY: Pay-to-fish ponds are a common commercial activity in Brazil. Samples of water and Oreochromis niloticus were examined by PCR to detect the presence of pathogenic strains of Escherichia coli (O157, enteropathogenic and shiga toxigenic). Several pathogenic strains were detected in this study, providing useful epidemiological information for the proper management of these environments and animals in order to prevent faecal pollution, reducing health risks to the Brazilian population.

Influence of chlorine added to drinking water during the preslaughter feed withdrawal on microbiology and morphology of the broiler gastrointestinal tract.

The objective of this experiment was to test the effects of the addition of chlorine to broiler drinking water during a 12-h preslaughter feed withdrawal period on reduction of the quantities of microorganisms, such as Escherichia coli and enterococci, in broiler crops and ceca. Reduction of these microorganisms would likely also reduce contamination of broiler meat by pathogenic bacteria during processing. It was also investigated if the chlorine caused some intestinal damage that could disseminate the microorganisms to the carcass. A total of 40 Cobb male broilers were used. Samples of crop and cecal content were collected for microbiological analysis, and duodenum and jejunum were used for morphological analysis from 10 birds in each treatment. The most probable number (MPN) of E. coli and enterococci in the collected samples of crop and ceca and the measure of the free residual chlorine in water were determined. The scanning electron microscopy from duodenum and jejunum was used to illustrate the mucosa integrity. The chlorine added to water was efficient in reducing the quantities of microorganisms in broiler crops and improved the integrity of the mucosa. Therefore, preslaughter feed withdrawal should be coupled with crop disinfection, because preslaughter feed withdrawal increases the MPN of enterococci and E. coli in broiler crops. So, it presents a higher risk for carcass contamination during slaughterhouse processing and, consequently, a higher risk for public health.

Origin of compartmentalization in food webs.

The response of an ecosystem to perturbations is mediated by both antagonistic and facilitative interactions between species. It is thought that a community's resilience depends crucially on the food web--the network of trophic interactions--and on the food web's degree of compartmentalization. Despite its ecological importance, compartmentalization and the mechanisms that give rise to it remain poorly understood. Here we investigate several definitions of compartments, propose ways to understand the ecological meaning of these definitions, and quantify the degree of compartmentalization of empirical food webs. We find that the compartmentalization observed in empirical food webs can be accounted for solely by the niche organization of species and their diets. By uncovering connections between compartmentalization and species' diet contiguity, our findings help us understand which perturbations can result in fragmentation of the food web and which can lead to catastrophic effects. Additionally, we show that the composition of compartments can be used to address the long-standing question of what determines the ecological niche of a species.

A network-based method for target selection in metabolic networks.

MOTIVATION: The lack of new antimicrobials, combined with increasing microbial resistance to old ones, poses a serious threat to public health. With hundreds of genomes sequenced, systems biology promises to help in solving this problem by uncovering new drug targets. RESULTS: Here, we propose an approach that is based on the mapping of the interactions between biochemical agents, such as proteins and metabolites, onto complex networks. We report that nodes and links in complex biochemical networks can be grouped into a small number of classes, based on their role in connecting different functional modules. Specifically, for metabolic networks, in which nodes represent metabolites and links represent enzymes, we demonstrate that some enzyme classes are more likely to be essential, some are more likely to be species-specific and some are likely to be both essential and specific. Our network-based enzyme classification scheme is thus a promising tool for the identification of drug targets. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

PhysioBank, PhysioToolkit, and PhysioNet: components of a new research resource for complex physiologic signals.

The newly inaugurated Research Resource for Complex Physiologic Signals, which was created under the auspices of the National Center for Research Resources of the National Institutes of Health, is intended to stimulate current research and new investigations in the study of cardiovascular and other complex biomedical signals. The resource has 3 interdependent components. PhysioBank is a large and growing archive of well-characterized digital recordings of physiological signals and related data for use by the biomedical research community. It currently includes databases of multiparameter cardiopulmonary, neural, and other biomedical signals from healthy subjects and from patients with a variety of conditions with major public health implications, including life-threatening arrhythmias, congestive heart failure, sleep apnea, neurological disorders, and aging. PhysioToolkit is a library of open-source software for physiological signal processing and analysis, the detection of physiologically significant events using both classic techniques and novel methods based on statistical physics and nonlinear dynamics, the interactive display and characterization of signals, the creation of new databases, the simulation of physiological and other signals, the quantitative evaluation and comparison of analysis methods, and the analysis of nonstationary processes. PhysioNet is an on-line forum for the dissemination and exchange of recorded biomedical signals and open-source software for analyzing them. It provides facilities for the cooperative analysis of data and the evaluation of proposed new algorithms. In addition to providing free electronic access to PhysioBank data and PhysioToolkit software via the World Wide Web (http://www.physionet. org), PhysioNet offers services and training via on-line tutorials to assist users with varying levels of expertise.

Mesoscopic modeling for nucleic acid chain dynamics.

To gain a deeper insight into cellular processes such as transcription and translation, one needs to uncover the mechanisms controlling the configurational changes of nucleic acids. As a step toward this aim, we present here a mesoscopic-level computational model that provides a new window into nucleic acid dynamics. We model a single-stranded nucleic as a polymer chain whose monomers are the nucleosides. Each monomer comprises a bead representing the sugar molecule and a pin representing the base. The bead-pin complex can rotate about the backbone of the chain. We consider pairwise stacking and hydrogen-bonding interactions. We use a modified Monte Carlo dynamics that splits the dynamics into translational bead motion and rotational pin motion. By performing a number of tests, we first show that our model is physically sound. We then focus on a study of the kinetics of a DNA hairpin--a single-stranded molecule comprising two complementary segments joined by a noncomplementary loop--studied experimentally. We find that results from our simulations agree with experimental observations, demonstrating that our model is a suitable tool for the investigation of the hybridization of single strands.

Decreased fractal correlation in diurnal physical activity in chronic fatigue syndrome.

OBJECTIVES: Our objectives were to study the temporal correlation of physical activity time series in patients with chronic fatigue syndrome (CFS) during normal daily life and to examine if it could identify the altered physical activity in these patients. METHODS: Fractal scaling exponents of diurnal and nocturnal physical activity time series in 10 CFS patients and 6 healthy control subjects (CON) were calculated by the detrended fluctuation analysis (DFA) and the wavelet transform modulus maxima (WTMM) method. We hypothesized that, due to their illness- and/or fatigue-induced resting episodes, altered physical activity patterns in CFS patients might be observed at the interruption of activity bursts. Thus, we further developed a new method, the wavelet transform negative modulus maxima (WTNMM) method, which could evaluate the temporal correlation at the interruption of activities. We compared the fractal scaling exponents for CFS and CON by each method. RESULTS: Both for CFS and CON, we found the fractal time structures in their diurnal physical activity records for at least up to 35 minutes. No group difference was found in nocturnal activities. The WTNMM method revealed that, in diurnal activities, CFS patients had significantly (p < 0.01) smaller fractal scaling exponent (0.87 +/- 0.03) compared to controls (1.01 +/- 0.03). Such a difference was identified neither by the DFA nor WTMM method. CONCLUSIONS: CFS patients had more abrupt interruptions of voluntary physical activity during diurnal periods in normal daily life, probed by the decreased correlation in the negative modulus maxima of the wavelet-transformed activity data, possibly due to their exaggerated fatigue.

Modeling heart rate variability by stochastic feedback.

We consider the question of how the cardiac rhythm spontaneously self-regulates and propose a new mechanism as a possible answer. We model the neuroautonomic regulation of the heart rate as a stochastic feedback system and find that the model successfully accounts for key characteristics of cardiac variability, including the 1/f power spectrum, the functional form and scaling of the distribution of variations of the interbeat intervals, and the correlations in the Fourier phases which indicate nonlinear dynamics.

Effect of insulin on protein catabolism after injury in young animals.

Injury is followed by a negative nitrogen balance, muscle protein breakdown and loss of body mass. The intensity of these changes correlates with trauma severity. Reversion of the catabolic state has long been attempted. Recently, it has been shown that the use of insulin might inhibit protein catabolism after severe trauma. The present study was undertaken to assess the effect of insulin on post-injury catabolism in young rabbits submitted to parenteral nutrition. Concomitantly, changes in liver and skeletal muscle nitrogen contents were also studied to elucidate the mechanism of insulin's anabolic effect after trauma. We found that only in catabolic states did insulin produce a significant nitrogen-sparing effect, probably due to the capacity of the hormone to inhibit muscle proteolysis.

Application of statistical physics to heartbeat diagnosis.

We present several recent studies based on statistical physics concepts that can be used as diagnostic tools for heart failure. We describe the scaling exponent characterizing the long-range correlations in heartbeat time series as well as the multifractal features recently discovered in heartbeat rhythm. It is found that both features, the long-range correlations and the multifractility, are weaker in cases of heart failure.

Statistical physics and physiology: monofractal and multifractal approaches.

Even under healthy, basal conditions, physiologic systems show erratic fluctuations resembling those found in dynamical systems driven away from a single equilibrium state. Do such "nonequilibrium" fluctuations simply reflect the fact that physiologic systems are being constantly perturbed by external and intrinsic noise? Or, do these fluctuations actually, contain useful, "hidden" information about the underlying nonequilibrium control mechanisms? We report some recent attempts to understand the dynamics of complex physiologic fluctuations by adapting and extending concepts and methods developed very recently in statistical physics. Specifically, we focus on interbeat interval variability as an important quantity to help elucidate possibly non-homeostatic physiologic variability because (i) the heart rate is under direct neuroautonomic control, (ii) interbeat interval variability is readily measured by noninvasive means, and (iii) analysis of these heart rate dynamics may provide important practical diagnostic and prognostic information not obtainable with current approaches. The analytic tools we discuss may be used on a wider range of physiologic signals. We first review recent progress using two analysis methods--detrended fluctuation analysis and wavelets--sufficient for quantifying monofractual structures. We then describe recent work that quantifies multifractal features of interbeat interval series, and the discovery that the multifractal structure of healthy subjects is different than that of diseased subjects.

[Evaluation of the hygienic and sanitary quality of water from shallow wells situated in an urban area: a comparison between the use of coliphages and bacterial indicators of fecal pollution]. / Avaliação da qualidade higiênico-sanitária da água de poços rasos localizados em uma área urbana: utilização de colifagos em comparação com indicadores bacterianos de poluição fecal.

One hundred and four water samples from eight private shallow wells situated in the urban area of Jaboticabal city, State of S. Paulo, Brazil, were submitted to coliphage, total coliform, fecal coliform and fecal streptococcus counts, for the purpose of discovering their hygienic and sanitary quality and of verifying the correlations between the coliphage numbers and the fecal pollution indicator bacteria. Ninety-six (92.3%) of the samples were not up to the microbiological potability standards. This result demonstrates the unsatisfactory hygienic and sanitary quality of the water samples. The results show also the absence of correlations among coliphages, and the fecal pollution indicator bacteria.

[Changes in physical, chemical, and microbiological characteristics of brines applied in the salting of mozzarella cheese during the period of utilization]. / Variação das características físico-químicas e microbiológicas das salmouras empregadas na salga de queijos tipo mussarela durante o período de sua utilização.

Variation of the physical, chemical and microbiological characteristics of brines during their utilization for salting mozzarella cheese. Forty brine samples used for submersion salting of mozzarella cheese in a dairy industry in the State of S. Paulo, Brazil, were analysed for the purpose of discovering the variation in the physical, chemical and microbiological characteristics observed over their period of utilization. The mean values preparation up to the 21st day of utilization of pH, sodium chloride and protein concentration varied from 7.21 to 5.76, from 27.1 to 24.5 and from zero to 0.126 mg/ml, respectively over the period from their. The mean values of the mesophilic microorganism counts and of the total and fecal coliforms MPN varied from 5.8 x 10 CFU/ml to 6.9 x 10(4) CFU/ml, from zero to 1.6 x 10(5)/100 ml and from zero to 1.1 x 10(5)/100 ml, respectively. Moreover, the mean values of mould and yeast and Staphylococcus positive coagulase counts varied from 0.4 x 10 CFU/ml to 2.0 x 10(3) CFU/ml and from zero to 1.3 x 10 CFU/ml, respectively. The results obtained suggest that the hygienic conditions during the preparation and the utilization of the brine were not satisfactory so that they may represent an important source of contamination for the cheeses. The quality of the product may be harmed, as a result of this fact, in such a way as to represent a potential hazard for the health of the consuming population.

[Health risk due to the consumption of raw milk commercialized without due authorization]. / Risco à saúde representado pelo consumo de leite cru comercializado clandestinamente.

Sixty raw milk samples commercialized without due authorization in the counties of Botucatu and S. Manuel, State of S. Paulo (Brazil), were submitted to mesophilic microorganism and coagulase-positive Staphylococcus and most probable number of total coliform and fecal coliform counts. Forty-one (68.3%) and 50 (83.3%) of the samples were found, respectively to contain mesophilic microorganisms and total coliforms above the maximum limits established by the Health Ministry for type C pasteurized milk. Thirty (50.0%) and 11 (18.3%) of the samples were found, respectively, to the contaminated by coagulase-positive Staphylococcus and fecal coliforms. Only 5 (8.3%) samples were found to comply with the required legal standards. The results showed the unsatisfactory hygienic and sanitary conditions of the raw milk and suggest the existence of great risk to the health of the consumers, especially when the product is taken without being boiled.

Imbalanced protein and appetite.

Free amino acid concentration in the plasma of rats fed on different diets were compared. The diets contained 7 g protein/100 g furnished by: casein, or common corn, or opaque 2 corn, or eggalbumin, or gelatin. A protein free diet was also included. The results showed that imbalance of the protein diet influenced the appetite; whenever the NE/E aminoacid ratio increased, body development, appetite and plasma albumin decreased. An inverse correlation between the NE/E of free aminoacids of the plasma and voluntary intake was observed. The results also show that the plasma aminogram did not reflect the composition of the protein in the diet. The results obtained are discussed.

[Sensitivity of different biological methods for differentiating the protein value of various foods]. / Sensibilidade de diferentes métodos biológicos para diferenciar valor protéico de alguns alimentos.

The nutritive value of proteins from different sources was studied. The value for PER, weight of the animals, IEC, NPR, NDpCal%, digestibility (D), and biological value (BV) was determined with diets containing 7% of total protein. The best results were obtained for milk, opaque-2 corn, rice and soybeans. The association of rice + soybeans was optimum. The results suggest also that it is advantageous to supplement wheat with cassava. Comparison of the results obtained by the different biological methods, classified by sensitivity for different protein qualities, revealed that the best methods are weight gain, PER and IEC better than NPR and NDpCal%, which in turn were better than BV, food intake and D (P less than 0.01).

Use of a global metabolic network to curate organismal metabolic networks.

The difficulty in annotating the vast amounts of biological information poses one of the greatest current challenges in biological research. The number of genomic, proteomic, and metabolomic datasets has increased dramatically over the last two decades, far outstripping the pace of curation efforts. Here, we tackle the challenge of curating metabolic network reconstructions. We predict organismal metabolic networks using sequence homology and a global metabolic network constructed from all available organismal networks. While sequence homology has been a standard to annotate metabolic networks it has been faulted for its lack of predictive power. We show, however, that when homology is used with a global metabolic network one is able to predict organismal metabolic networks that have enhanced network connectivity. Additionally, we compare the annotation behavior of current database curation efforts with our predictions and find that curation efforts are biased towards adding (rather than removing) reactions to organismal networks.

Drosophila Eye Nuclei Segmentation Based on Graph Cut and Convex Shape Prior.

The rapid advance in three-dimensional (3D) confocal imaging technologies is rapidly increasing the availability of 3D cellular images. However, the lack of robust automated methods for the extraction of cell or organelle shapes from the images is hindering researchers ability to take full advantage of the increase in experimental output. The lack of appropriate methods is particularly significant when the density of the features of interest in high, such as in the developing eye of the fruit fly. Here, we present a novel and efficient nuclei segmentation algorithm based on the combination of graph cut and convex shape prior. The main characteristic of the algorithm is that it segments nuclei foreground using a graph cut algorithm and splits overlapping or touching cell nuclei by simple convex and concavity analysis, using a convex shape assumption for nuclei contour. We evaluate the performance of our method by applying it to a library of publicly-available two-dimensional (2D) images that were hand-labeled by experts. Our algorithm yields a substantial quantitative improvement over other methods for this benchmark. For example, our method achieves a decrease of 3.2 in the Hausdorff distance and an decrease of 1.8 per slice in the merged nuclei error.

Proteinograma sérico de éguas com placentite ascendente e seus respectivos neonatos: dados preliminares / Serum protein concentrationin mares with ascending placentitis and their newborns: preliminary data

Este estudo teve por objetivo estabelecer o proteinograma sérico em éguas com placentite induzida e em seus respectivos neonatos. Foram coletadas amostras de sangue das éguas em oito momentos diferentes e dos potros em quatro momentos. Para obtenção da concentração das frações proteicas, utilizou-se eletroforese em gel de acrilaminada contendo dodecil sulfato de sódio (SDS-PAGE). No método utilizado, foram observadas 23 bandas proteicas, cujos pesos moleculares variaram de 16KDa a 245KDa, sendo possível a identificação das seguintes frações: 175KDa, 102KDa, 83KDa, 63KDa, 50KDa, 41KDa, 39KDa e 28KDa. De todas as bandas proteicas encontradas, somente as de 39KDa e 41KDa apresentaram alteração na cinética nos momentos avaliados. De acordo com a solução marcadora, pode-se sugerir que essas proteínas seriam alfa1-glicoproteína ácida (39KDa) e haptoglobina (41KDa). A concentração de imunoglobulinas nos potros apresentou aumento significativo a partir das 12 horas de nascimento. Não está elucidado se estes níveis refletem a persistência do processo inflamatório placentário ou se são alterações fisiológicas do periparto. Não foram observadas alterações na cinética das proteínas nos potros nas primeiras 48 horas.(AU)

The aim of this paper was to identify the serum acute phase protein concentration in mares with induced placentitis and their neonates. Blood samples were collected from the mares in 8 different moments, and from the foals, in 4 moments. To obtain the concentration of protein fractions acrilaminada gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE) was used. In the used method 23 protein bands whose molecular weights ranged from 16kDa to 245kDa were observed, it is possible to identify the following fractions: 175kDa, 102kDa, 83kDa, 63kDa, 50kDa, 41kDa, 39kDa and 28kDa. Of all the protein bands found only the 39KDa and 41KDa have changes in the kinetics in the evaluated times. According to the marker solution, we would suggest that these proteins are alfa1-acid glycoprotein (39kDa) and haptoglobin (41kDa). The concentration of immunoglobulins in foals increased significantly from 12 hours of birth.(AU)