Biochemical properties, enterohaemolysin production and plasmid carriage of Shiga toxin-producing Escherichia coli strains

Thirty-eight strains of Shiga toxin-producing Escherichia coli (STEC) were characterised in terms of biochemical properties, enterohaemolysin production and plasmid carriage. A wide variation in the biochemical properties was observed among the STEC, with 14 distinct biotypes identified. Biotype 1 was the most common, found in 29% of the strains. Enterohaemolysin production was detected in 29% of the strains. Most of the bacterial strains (95%) carried one or more plasmids and considerable heterogeneity in size and combinations was observed. Seven distinct plasmid profiles were identified. The most common profile, characterised by the presence of a single plasmid of ~90 kb, was found in 50% of these strains. These data indicate extensive diversity among STEC strains. No correlation was found among biotype, serotype, enterohaemolysin production and plasmid profile.

Towards an understanding of the epigenetics of schistosomes: a comparative epigenomic study

As in perhaps all eukaryotes, schistosomes use a supplementary information transmitting system, the epigenetic inheritance system, to shape genetic information and to produce different phenotypes. In contrast to other important parasites, the study of epigenetic phenomena in schistosomes is still in its infancy. Nevertheless, we are beginning to grasp what goes on behind the epigenetic scene in this parasite. We have developed techniques of native chromatin immunoprecipitation (N-ChIP) and associated the necessary bioinformatics tools that allow us to run genome-wide comparative chromatin studies on Schistosoma mansoni at different stages of its life cycle, on different strains and on different sexes. We present here an application of such an approach to study the genetic and epigenetic basis for a phenotypic trait, the compatibility of S. mansoni with its invertebrate host Biomphalaria glabrata. We have applied the ChIP procedure to two strains that are either compatible or incompatible with their intermediate host. The precipitated DNA was sequenced and aligned to a reference genome and this information was used to determine regions in which both strands differ in their genomic sequence and/or chromatin structure. This procedure allowed us to identify candidate genes that display either genetic or epigenetic difference between the two strains.

Widespread distribution of CTX-M and plasmid-mediated AmpC β-lactamases in Escherichia coli from Brazilian chicken meat

The dissemination of plasmid-mediated antimicrobial resistance genes may pose a substantial public health risk. In the present work, the occurrences ofblaCTX-M and plasmid-mediated ampCand qnrgenes were investigated in Escherichia colifrom 16 chicken carcasses produced by four commercial brands in Brazil. Of the brands tested, three were exporters, including one of organic chicken. Our study assessed 136 E. coli isolates that were grouped into 77 distinct biotypes defined by their origin, resistance profiling, the presence of β-lactamase and plasmid-mediated quinolone resistance genes and enterobacterial repetitive intergenic consensus-polimerase chain reaction typing. TheblaCTX-M-15, blaCTX-M-2 andblaCTX-M-8 genes were detected in one, 17 and eight different biotypes, respectively (45 isolates). Twenty-one biotypes (46 isolates) harboured blaCMY-2.Additionally, blaCMY-2 was identified in isolates that also carried either blaCTX-M-2 orblaCTX-M-8. The qnrB and/orqnrS genes occurred in isolates carrying each of the four types of β-lactamase determinants detected and also in oxyimino-cephalosporin-susceptible strains. Plasmid-mediated extended-spectrum β-lactamase (ESBL) and AmpC determinants were identified in carcasses from the four brands tested. Notably, this is the first description ofblaCTX-M-15 genes in meat or food-producing animals from South America. The blaCTX-M-8, blaCTX-M-15 andblaCMY-2 genes were transferable in conjugation experiments. The findings of the present study indicate that plasmid-mediated ESBL and AmpC-encoding genes are widely distributed in Brazilian chicken meat.

The decision of an obese woman to have bariatric surgery: the social phenomenology

Objective To understand the process by which an obese woman decides to have bariatric surgery. Method A qualitative survey with a social phenomenology approach, carried out in 2012, with 12 women, using the phenomenological interview. Results A woman bases the decision to have the surgery on: the inappropriateness of her eating habits; a physical appearance that is incompatible with an appearance that is standardized by society; the social prejudice that she has to live with; the limitations imposed by obesity; and her lack of success with previous attempts to lose weight. Outcomes that she hopes for from the decision to have the surgery include: restoring her health; achieving social inclusion; and entering the labor market. Conclusion This study allows one to reflect that prescriptive actions do not give a satisfactory response to a complexity of the subjective questions involved in the decision to have surgery for obesity. For this, what is called for is a program of work based on an interdisciplinary approach, and training that gives value to the bio-psycho-social aspects involved in a decision in favor of surgical treatment.

Establishment of an in vitro system for studies on the induced resistance of cotton to Xanthomonas campestris pv. malvacearum

An in vitro system for studying the resistance response of cotton (Gossypium hirsutum L.) to Xanthomonas campestris pv. malvacearum was investigated. Cell suspension cultures, established from hypocotyl-derived callus of cotton cultivar 101-102B, were treated with bacterial extracellular polysaccharides (EPS) extracted from the incompatible race 18 of X. campestris pv. malvacearum. EPS at 600 mug/mL caused pronounced darkening of the suspension cultures, as indicative of cell death, 48 hours after incubation. Protein electrophoresis analysis of the time course of EPS-treated cells showed differential accumulation of several protein bands after 12-24 hours. The time course of protein accumulation and cell death was consistent with an elicitor-mediated hypersensitive response.

Resistance spectra of six elite breeding lines of upland rice to Pyricularia grisea

The objective of this work was to evaluate the resistance spectra of six elite breeding lines of rice, developed for improved yield and grain quality, in inoculation tests in the greenhouse and in the field. Forty-six isolates of Pyricularia grisea collected from the cultivar Primavera, 31 from the cultivar Maravilha and 19 from six elite breeding lines, totaling 96 were utilized for inoculations. Out of 11 international and 15 Brazilian pathotypes, IC-1, IB-9, and BD-16, respectively, were identified as most frequent isolates collected from the cultivar Primavera. The isolates retrieved from Maravilha belong to four international and 11 Brazilian pathotypes, the predominant ones being IB-9 and IB-49 and BB-1 and BB-21, respectively. Lines CNAs 8711 and CNAs 8983 showed resistant reaction to all test isolates from Maravilha, while CNAs 8983 was susceptible to three isolates of Primavera pertaining to the pathotype IC-1. A majority of isolates exhibiting compatible reaction to Primavera were incompatible to Maravilha and vice-versa.Field assessment of rice blast utilizing the area under disease progress curve as a criterion for measuring disease severity showed significant differences among the six breeding lines. The isolates of P. grisea exhibiting differential reaction on breeding lines can be utilized in pyramiding resistance genes in new upland rice cultivars.

Impact of increasing mean air temperature on the development of rice and red rice

The objective of this study was to assess the development response of cultivated rice and red rice to different increases in minimum and maximum daily air temperatures, in Santa Maria, Rio Grande do Sul State, Brazil. One hundred years climate scenarios of temperatures 0, +1, +2, +3, +4, and +5ºC, with symmetric and asymmetric increases in minimum and maximum daily air temperatures were created, using the LARS-WG Weather Generator, and a 1969-2003 database. Nine cultivated rice genotypes (IRGA 421, IRGA 416, IRGA 417, IRGA 420, BRS 7 TAIM, BR-IRGA 409, EPAGRI 109, EEA 406 and a hybrid), and two red rice biotypes (awned black hull-ABHRR, and awned yellow hull-AYHRR) were used. The dates of panicle differentiation (R1), anthesis (R4), and all grains with brown hulls (R9) were estimated with a nonlinear simulation model. Overall, the duration of the emergence-R1 phase decreased, whereas the duration of the R1-R4 and R4-R9 phases most often increased, as temperature increased in the climate change scenarios. The simulated rice development response to elevated temperature was not the same, when the increase in minimum and maximum temperature was symmetric or asymmetric.

Análise térmica aplicada à caracterização da sinvastatina em formulações farmacêuticas

Thermogravimetry (TG) and differential scanning calorimetry (DSC) are used in pharmaceutical studies for drugs characterization, purity, formulations compatibility, polymorphism identification, stability evaluation, and thermal decomposition of drugs and pharmaceutical formulations. Simvastatin showed fusion at 138.5 ºC and thermal stability up to 248 ºC. Simvastatin was incompatible with preservative excipient butylhydroxyanisole (BHA) performing a process of crystal amorphization. The drug showed morphological polymorphism, where it has the same unit cell but with different crystal habits according to the recrystallization solvent.

Effect of continuous growing of resistant soybean genotypes on Meloidogyne arenaria race 1 reproduction

Even though resistance is the most promising tactic for root-knot nematode management on soybean (Glycine max), virulent biotypes may occur and be selected on specific resistant plant genotypes. In the present study, reproduction rate of Meloidogyne arenaria race 1 increased after four sequences of continuous culture of the parasite on resistant soybean genotypes.

Expression of resistance in rice hybrids to Pyricularia grisea

Thirty-nine rice (Oryza sativa) hybrids and their restorers were assessed for vertical resistance to Pyricularia grisea in the rice blast nursery, and in artificial inoculation tests with two pathotypes, under controlled greenhouse conditions. The hybrids were developed from cytoplasmic genetic male sterile lines 046I and IR 58025A, derived from WA cytoplasm. In the rice blast nursery all hybrids showed susceptible reaction varying from 5 to 9. Compatible and incompatible leaf blast reactions of hybrids to two pathotypes, IC-1 and IB-45, were observed in inoculation tests. A majority of the hybrids were resistant when the restorer was resistant. However, seven of the 25 F1 hybrids exhibited susceptible reactions even when one of the parents was resistant to a pathotype. The partial resistance of 11 hybrids and their parents that showed compatible reactions to two pathotypes was analyzed. Differential interaction between isolates and genotypes was observed for partial resistance in relation to both disease severity and lesion number indicating the specific nature of partial resistance.

Resistance spectra of wheat cultivars and virulence diversity of Magnaporthe grisea isolates in Brazil

Seventy-two monoconidial isolates of Magnaporthe grisea were obtained from the States of Mato Grosso do Sul and Paraná. The isolates were inoculated on seedlings of 20 wheat (Triticum aestivum) cultivars under greenhouse conditions. The virulence diversity of M. grisea was assessed based on compatible and incompatible reactions of leaf blast on wheat cultivars. Fifty-four distinct virulence patterns were identified on test cultivars among the isolates collected from the two wheat growing States. Sixteen of these isolates corresponding to 22.2% showed similar virulence pattern. None of the wheat cultivars was resistant to all isolates of M. grisea, but the cultivars differed in degree of resistance as measured by the relative spectrum of resistance (RSR) and disease index (DI). Among the cultivars the RSR ranged from 0 to 53.3% and DI from 0.4662 to 0.9662 (0 to 1 scale). The wheat cultivar BR18 exhibited a broad resistance spectrum in relation to the rest of the tested cultivars to the isolates of M. grisea, and can be used in wheat resistance breeding.

Virulence and rep-PCR analysis of Pyricularia grisea isolates from two Brazilian upland rice cultivars

The phenotypic and genetic diversity of 77 isolates of Pyricularia grisea collected from two upland rice cultivars, Maravilha and Primavera, was studied. Isolates exhibiting compatible reaction to cv.Primavera were incompatible to cv.Maravilha and vice versa, with the exception of six isolates that were compatible to both cultivars. The virulence of isolates from cv. Maravilha on 32 test genotypes of rice was significantly higher (t = 9.09, p < 0.0001) than the isolates from cv.Primavera. A phenogram constructed from virulence data showed two main groups, one constituted mainly of isolates from cv.Primavera (97.6%) and the other of isolates from cv.Maravilha (91.17%). Rep-PCR analysis of isolates using two primers designed from sequences of Pot2 showed that isolates could be clustered broadly into two groups. The average similarity within a cluster of isolates from cv.Primavera was significantly greater than the average similarity among the isolates of cv.Maravilha (t = 5.37, p < 0.0001). There was close correspondence between clusters based on PCR and virulence data (r = 0.48, p < 0.011). The results showed that isolates of P. grisea were cultivar specific and had low phenotypic and genetic diversity.

PCR amplification and sequence analyses of reverse transcriptase-like genes in Crinipellis perniciosa isolates

Reverse transcriptase (RT) sequence analysis is an important technique used to detect the presence of transposable elements in a genome. Putative RT sequences were analyzed in the genome of the pathogenic fungus C. perniciosa, the causal agent of witches' broom disease of cocoa. A 394 bp fragment was amplified from genomic DNA of different isolates of C. perniciosa belonging to C-, L-, and S-biotypes and collected from various geographical areas. The cleavage of PCR products with restriction enzymes and the sequencing of various RT fragments indicated the presence of several sequences showing transition events (G:C to A:T). Southern blot analysis revealed high copy numbers of RT signals, forming different patterns among C-, S-, and L-biotype isolates. Sequence comparisons of the predicted RT peptide indicate a close relationship with the RT protein from thegypsy family of LTR-retrotransposons. The possible role of these retrotransposons in generating genetic variability in the homothallic C. perniciosa is discussed.

On Intellectus Agens and Aristotellian separate substances: Aquinas' waterloo

The present paper deals with Saint Thomas's commentary to Aristotle's De Anima III, in wich we find the famous analogy of light. It is sustained that due to the limitations of the analogy, Saint Thomas is forced to introduce a series of Neo-platonic elements incompatible with Aristotle's philosophy. The author means to explain this "betrayal" to Aristotle's philosophy by one of his most credited commentators. It is concluded that in order to reconcile the pagan world with the Catholic theology, Thomas Aquinas needs to redirect Aristotle through a less economical argument; that is, the introduction of the Intellectus Agens

Bayle historien et critique du matérialisme dans le dictionnaire

Bayle affirme que les atomistes auraient dû rester fidèles à une curieuse thèse attribuée au fondateur de l'atomisme, Démocrite, à savoir que les atomes ont une âme. En effet, montre Bayle par plusieurs arguments, il est impossible que la pensée émerge de la matière. Dès lors, l'atomisme doit se donner d'emblée la pensée comme présente dans chacun des atomes. Dans la même ligne, Bayle montre que, plus généralement, tout matérialisme conséquent doit être un panpsiquismo : toutes les parties de la matière doivent penser, et penser toujours. Mais cela conduit à des conséquences difficilement acceptables, telles que des cadavres pensants. De plus, le conseil qu'il donne aux matérialistes (suivre Démocrite) est une mesure qu'il croit en réalité inapplicable, puisque selon Bayle la pensée est incompatible avec l'étendue, leurs propriétés étant opposées et chaque substance n'ayant qu'un attribut. Ce que Bayle entend donc faire, dans cette fantaisie historique sur Démocrite, est de réduire le matérialisme à une position absurde.