RESUMO

This article investigates aspects of similarity between complete sequences of mitochondrial DNA by determining the distribution of the relative frequencies of words with different lengths and the characteristics of their relevance throughout the sequences. The degree of similarity is obtained by comparing the distances between words contained within these sequences. Our results indicate that the best groupings among different species depend on the lengths of words and their respective relative frequencies. We also observed that the longer the word the more consistent the grouping between the sequences becomes. The application of our results, together with the perspective of analyzing DNA sequences belonging to a single biological species, may be important for the construction of phylogenetic trees, which are appropriate structures for understanding the evolutionary history of the species.

Assuntos

RESUMO

The aim of this study was to diagnose dermatophytosis in pets and investigate the presence of dermatophytes in their home environment. Samples from hair coat were collected from 70 pets: 47 dogs, 19 cats, three guinea pigs and one rabbit. After mycological culture, 188 samples were collected from the household environments in 26 homes: 78 from places were of predominantly used by the tutors, 66 from places used by the animals, 44 from flooring, and 24 samples from contactees. Samples were seeded on Mycosel agar, incubated at 25°C, and the colonies were identified by their macro-and-microscopic characteristics. Dermatophytes were found in 37.1% of the samples originating from the sick animals. Microsporum canis was the most prevalent species, isolated in 12 dogs and eight cats; Trichophyton quinckeanum in three guinea pigs, Microsporum gypseum in two dogs and Trichophyton mentagrophytes in one cat. Dermatophytes were found in 69.2% of the surveyed homes; 29.5% of the places/objects predominantly used by the tutors, 42.4% mainly used by the animals, 31.8% from floors, and 50% from contactees. The meeting of dermatophytes in animals and in the household environment confirms the possibility of transmission by direct or indirect contact and their importance in public health.(AU)

O objetivo deste trabalho foi diagnosticar dermatofitose em pets e pesquisar dermatófitos em seu ambiente domiciliar. Colheram-se amostras de 70 pets, 47 cães, 19 gatos, três cobaias e um coelho. Visitaram-se 26 residências dos animais positivos em cultura micológica para a doença, colhendo-se 188 amostras do ambiente: 78 de locais de uso predominante dos tutores, 66 de uso dos animais e 44 de pisos; também foram colhidas 24 amostras de animais contactantes. As amostras clínicas foram semeadas em ágar Mycosel, incubadas a 25°C, e as colônias identificadas por suas características macro e microscópicas. Dermatófitos foram isolados em 37,1% dos animais suspeitos. Microsporum canis foi o mais frequente, sendo isolado de 12 cães e oito gatos, Trichophyton quinckeanum de três cobaias, Microsporum gypseum de dois cães e Trichophyton mentagrophytes de um gato. Foram encontrados dermatófitos em 69,2% das casas pesquisadas, isolando-se esses fungos em 29,5% dos locais/objetos de uso predominante dos tutores, 42,4% de uso predominante dos animais, 31,8% de pisos e 50% dos animais contactantes. O encontro de dermatófitos nos animais e em superfícies inanimadas nas residências confirma a possibilidade de transmissão de dermatofitose por contato direto e indireto e sua importância em saúde pública.(AU)

Assuntos

RESUMO

The aim of this study was to diagnose dermatophytosis in pets and investigate the presence of dermatophytes in their home environment. Samples from hair coat were collected from 70 pets: 47 dogs, 19 cats, three guinea pigs and one rabbit. After mycological culture, 188 samples were collected from the household environments in 26 homes: 78 from places were of predominantly used by the tutors, 66 from places used by the animals, 44 from flooring, and 24 samples from contactees. Samples were seeded on Mycosel agar, incubated at 25°C, and the colonies were identified by their macro-and-microscopic characteristics. Dermatophytes were found in 37.1% of the samples originating from the sick animals. Microsporum canis was the most prevalent species, isolated in 12 dogs and eight cats; Trichophyton quinckeanum in three guinea pigs, Microsporum gypseum in two dogs and Trichophyton mentagrophytes in one cat. Dermatophytes were found in 69.2% of the surveyed homes; 29.5% of the places/objects predominantly used by the tutors, 42.4% mainly used by the animals, 31.8% from floors, and 50% from contactees. The meeting of dermatophytes in animals and in the household environment confirms the possibility of transmission by direct or indirect contact and their importance in public health.(AU)

O objetivo deste trabalho foi diagnosticar dermatofitose em pets e pesquisar dermatófitos em seu ambiente domiciliar. Colheram-se amostras de 70 pets, 47 cães, 19 gatos, três cobaias e um coelho. Visitaram-se 26 residências dos animais positivos em cultura micológica para a doença, colhendo-se 188 amostras do ambiente: 78 de locais de uso predominante dos tutores, 66 de uso dos animais e 44 de pisos; também foram colhidas 24 amostras de animais contactantes. As amostras clínicas foram semeadas em ágar Mycosel, incubadas a 25°C, e as colônias identificadas por suas características macro e microscópicas. Dermatófitos foram isolados em 37,1% dos animais suspeitos. Microsporum canis foi o mais frequente, sendo isolado de 12 cães e oito gatos, Trichophyton quinckeanum de três cobaias, Microsporum gypseum de dois cães e Trichophyton mentagrophytes de um gato. Foram encontrados dermatófitos em 69,2% das casas pesquisadas, isolando-se esses fungos em 29,5% dos locais/objetos de uso predominante dos tutores, 42,4% de uso predominante dos animais, 31,8% de pisos e 50% dos animais contactantes. O encontro de dermatófitos nos animais e em superfícies inanimadas nas residências confirma a possibilidade de transmissão de dermatofitose por contato direto e indireto e sua importância em saúde pública.(AU)

Assuntos

RESUMO

BACKGROUND: All the currently recognized Malassezia species have been isolated from mammals. However, only a few of them have been isolated from birds. In fact, birds have been less frequently studied as carriers of Malassezia yeasts than mammals. AIM: In this study we describe two new taxa, Malassezia brasiliensis sp. nov. and Malassezia psittaci sp. nov. METHODS: The isolates studied in this publication were isolated from pet parrots from Brazil. They were characterized using the current morphological and physiological identification scheme. DNA sequencing and analysis of the D1/D2 regions of the 26S rRNA gene, the ITS-5.8S rRNA gene sequences and the ß-tubulin gene were also performed. RESULTS: The strains proposed as new species did not completely fit the phenotypic profiles of any the described species. The validation of these new species was supported by analysis of the genes studied. The multilocus sequence analysis of the three loci provides robust support to delineate these species. CONCLUSIONS: These studies confirm the separation of these two new species from the other species of the genus Malassezia, as well as the presence of lipid-dependent Malassezia yeasts on parrots.

Assuntos

RESUMO

An exacerbated type 1 response to leishmanial antigens is the basis of tissue destruction observed in mucosal leishmaniasis (ML). After therapy, a persistent production of high levels of inflammatory cytokines can confer a poor prognosis. Herein we investigated whether the clinical conditions defined during the active phase of ML affect the magnitude of long-term anti-Leishmania immune response. Twenty clinically cured ML cases were studied. Peripheral blood mononuclear cells (PBMC) were cultured with L. braziliensis antigens (Lb-Ag), Toxoplasma gondii antigens (Tg-Ag), concanavalin-A (Con-A) or medium alone, and the lymphocyte proliferative response and cytokine secretion were quantified. Medical records were reviewed for Montenegro skin test (MST) during diagnosis, duration of ML disease or time elapsed after clinical cure. The duration of disease was correlated positively with MST (r = 0·61). Lb-Ag induced interferon (IFN)-γ was correlated positively with duration of illness (r = 0·69) as well as the frequency of secreting cells [enzyme-linked immunospot (ELISPOT)] assay. No association was observed for Tg-Ag or Con-A. Disease duration was correlated negatively with interleukin (IL)-10 production (r = -0·76). Moreover, a negative correlation between length of time after clinical cure and TNF levels (r = -0·94) or the IFN-γ : IL-10 ratio (r = -0·89) were also seen. We suggest that the magnitude of the IFN-γ inflammatory response triggered by ML can be driven by the time of leishmanial antigens exposition during the active phase of the disease. This pattern could persist even long-term after cure. However, despite IFN-γ levels, the decrease of the TNF and IFN-γ : IL-10 ratio reflects the control of proinflammatory responses achieved by cure of ML, possibly preventing disease relapses.

Assuntos

RESUMO

The aim of this study was to identify phenotypic changes in a laboratory-derived strain of ertapenem-resistant Escherichia coli (Ec-ERT) when compared to its susceptible parent strain (Ec-WT). In both strains, we assessed both the effects of ertapenem via time-kill curves and the occurrence of cross resistance with other beta-lactams. The strains were compared based on growth pattern, biochemical-physiological profile and changes in the subproteome using 2D-DIGE followed by MALDI-TOF/TOF MS. To assess virulence, we employed a murine model of intraperitoneal infection in which we investigated the invasiveness of both strains. Growth persistence of the laboratory-derived resistant strain was observed via the time-kill curve assay, but cross resistance was not observed for other beta-lactams. We also observed a slower growth rate and changes in the biochemical and physiological characteristics of the drug-resistant bacteria. In the resistant strain, a total of 51 protein spots were increased in abundance relative to the wild-type strain, including an outer membrane protein A, which is related to bacterial virulence. The mouse infection assay showed a higher invasiveness of the Ec-ERT strain in relation to the Ec-WT strain. In conclusion, the alterations driven by ertapenem in E. coli reinforce the idea that antimicrobial agents may interfere in several aspects of bacterial cell biology, with possible implications for host-bacteria interactions.

Assuntos

RESUMO

A restricted angular random-walk model to build up polypeptide structures, which encompasses properties of the dihedral-angle Ramachandran map of folded proteins, is proposed to study the role of stochasticity on the compactness of the native state of proteins. Sample structures will be built with lengths ranging from 125 up to 400 amino acids for the different fractions of secondary structure motifs, from which dihedral angles were randomly chosen according to narrow Gaussian probability distributions. Physical properties of these polypeptide protein backbones such as the radius of gyration, the compactness parameter, the number of contacts, and the associated energy were computed and analyzed from an ensemble of thousands of realizations of protein peptide chains built with different rates of alpha-helix or beta-strand motifs. Such geometric and physical parameters are compared to data from several globular proteins extracted from the Protein Data Bank indicating that a certain (small fraction) randomness is an essential ingredient for achieving the folded state of proteins, suggesting that they are neither driven by deterministic nor random-walk processes.

Assuntos

RESUMO

Ertapenem and piperacillin/tazobactam are beta-lactam antibiotics with a broad spectrum of activity, used for the treatment of mixed infections, in which Bacteroides fragilis plays an important etiological role. The aim of this study was to select strains of B. fragilis resistant to these drugs and correlate the phenotype profiles of these lineages with changes in the virulence of the original bacterium. B. fragilis ATCC 25285, sensitive to the drugs listed, was used in this study. Strains resistant to these drugs were obtained by multi-step method and this condition was confirmed by comparing the time-kill curve of the original strain with those curves obtained from derived-resistant strains. To assess the virulence, germ-free mice were challenged intragastrically with the original strain or those derived-resistant. The mouse infection by the piperacillin/tazobactam-resistant B. fragilis strain produced increased levels of C-reactive protein, alkaline phosphatase and white blood cells and reduced platelet counts, what may indicate that acquisition of piperacillin/tazobactam resistance may enhance the pathogenic properties of these B. fragilis strains.

Assuntos

RESUMO

Suitable levels of interferon (IFN)-gamma and interleukin (IL)-10 seem to favour the outcome of cutaneous leishmaniasis (CL), while high IFN-gamma and low IL-10 production are associated with severity of mucosal leishmaniasis (ML). Considering that cytokine balance is important for the maintenance of protective responses in leishmaniasis, our aim was to investigate leishmanial antigens-induced IFN-gamma and IL-10 levels maintained in healed individuals who had different clinical outcomes of Leishmania infection. Thirty-three individuals who recovered from L. braziliensis infection were studied: cured CL (CCL), cured ML (CML), spontaneous healing of CL (SH) or asymptomatic individuals (ASY). Cytokines were quantified by enzyme-linked immunosorbent assay (ELISA) in culture supernatants of L. braziliensis-stimulated peripheral blood mononuclear cells (PBMC). IFN-gamma levels were higher in CML (7593 +/- 5994 pg/ml) in comparison to SH (3163 +/- 1526 pg/ml), ASY (1313 +/- 1048 pg/ml) or CCL (1897 +/- 2087 pg/ml). Moreover, cured ML cases maintained significantly lower production of IL-10 (127 +/- 57.8 pg/ml) in comparison to SH (1373 +/- 244 pg/ml), ASY (734 +/- 233 pg/ml) or CCL (542 +/- 375 pg/ml). Thus, a high IFN-gamma/IL-10 ratio observed in CML can indicate unfavourable cytokine balance. On the other hand, no significant difference in the IFN-gamma/IL-10 ratio was observed when CCL individuals were compared to SH or ASY subjects. In conclusion, even after clinical healing, ML patients maintained a high IFN-gamma/IL-10 secretion profile in response to leishmanial antigens. This finding can explain a delayed down-modulation of exacerbated inflammatory responses, which can be related in turn to the necessity of prolonged therapy in ML management. Conversely, lower IFN-gamma/IL-10 balance observed in CCL, SH and ASY individuals can represent a better-modulated immune response associated with a favourable prognosis.

Assuntos

RESUMO

The occurrence of serum antibodies to Borrelia burgdorferi in professionals in close contact with wild animals was determined. Seventy eight technicians workers coming from two São Paulo public institutions housing wild animals had their blood collected (serum samples). All samples were submitted to ELISA for IgM and IgG antibodies against Borrelia burgdorferi. The results showed five positive (6.4%), two suspect (2.6%) and 71 negatives (91%) samples. Based on positive results it is concluded that the infection level is higher to that detected in the general population and similar to values of endemic areas, concluding that this assessed population could be considered at risk for Lyme disease.(AU)

Assuntos