RESUMO
AIM: To evaluate the association of the polar and lateral flagella with biofilm formation on plastic surfaces in 76 Aeromonas caviae strains isolated from environment (lagoon water), food (vegetables, fish and cheese) and human source (faeces). METHODS AND RESULTS: Both polar (flaA) and lateral (lafA) flagellin genes have been investigated by means of PCR and colony blot hybridization assays. The ability to form biofilm in polystyrene microtitre plates was evaluated and correlated with the presence and absence from these genes. The flaA and lafA genes had a frequency of 94% and 71%, respectively. All lafA(+) strains were also flaA(+) . Biofilm formation was observed in 72% of strains. Ninety-four per cent of flaA(+) lafA(+) strains could form biofilm and those that presented an intense biofilm production harboured both genes. All flaA(-) lafA(-) isolates, as well as 76% of flaA(+) lafA(-) strains, were incapable of forming biofilm. All the fish strains were flaA(+) lafA(+) and displayed higher biofilm formation (88%). Lagoon water samples exhibited lower positivity rate for the lafA gene (57%) and decreased ability to produce biofilm (39%). CONCLUSIONS: Both polar and lateral flagellar function contribute to biofilm formation in Aer. caviae strains. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides evidence for the association of both flagella with biofilm formation, a factor required for pathogenicity of Aer. caviae strains of varied sources, especially food and human.
Assuntos
Aeromonas caviae/crescimento & desenvolvimento , Aeromonas caviae/genética , Biofilmes/crescimento & desenvolvimento , Flagelina/genética , Flagelina/metabolismo , Aeromonas caviae/patogenicidade , Aderência Bacteriana/genética , Flagelos/genética , Flagelos/metabolismo , Genótipo , Humanos , PlásticosRESUMO
Leishmania (V.) braziliensis, the causative agent of mucocutaneous leishmaniasis in the New World, may present an LD1 type genomic amplification that appears as a small 245 kb linear chromosome, and is not clearly associated to the presence of a selection agent. A bt1 gene, codifying for a biopterin transporter protein, was identified in this small chromosome. Leishmania are auxotrophic for pterins and one of the proposed explanations for the appearance of this amplification is the improvement of biopterin capture by the parasite. We analyzed some biological aspects of two lineages of L. braziliensis strain M2903, with and without the small amplified chromosome. We showed differences in infectivity of these lineages, in macrophages and the insect vector Lutzomyia longipalpis, as well as in the uptake and metabolization of intermediates of the Leishmania biopterin salvage pathway. Our results suggest that the genomic amplification favors survival due to improved biopterin capture and at the same time hinders the infective capability, suggesting that within a population different parasites can perform different roles.
Assuntos
Leishmania braziliensis/genética , Leishmania braziliensis/patogenicidade , Leishmaniose Mucocutânea/parasitologia , Proteínas de Membrana Transportadoras/genética , Proteínas de Protozoários/genética , Animais , Linhagem Celular , Cromossomos/genética , Amplificação de Genes , Insetos Vetores/parasitologia , Leishmania braziliensis/metabolismo , Macrófagos/parasitologia , Metotrexato/farmacologia , Camundongos , Pteridinas/metabolismoRESUMO
The neurotensin (NT) produced in the hypothalamus and in pituitary gonadotrophs and thyrotrophs participates in neuroendocrine regulation. Recently, the involvement of this peptide in normal and neoplastic cell proliferation has been postulated. In the present study, we evaluated the expression of NT and its receptors (NTR1, 2 and 3) in a series of 50 pituitary adenomas [11 growth hormone (GH)-, eight prolactin (PRL)-, four adrenocorticotrophic hormone (ACTH)- and 27 nonfunctioning adenomas]. NT mRNA expression was significantly higher in functioning compared to nonfunctioning adenomas and with normal pituitary. Nonfunctioning pituitary adenomas showed lower expression of NT mRNA than normal pituitary. In the immunohistochemical study of functioning adenomas, NT was colocalised with GH, PRL and ACTH secreting cells. In nonfunctioning adenomas, the NT immunoreactivity intensity was variable among the samples. NTR3 mRNA expression was observed in all examined samples and was higher in the adenomas, both functioning and nonfunctioning, compared to normal pituitary. By contrast, NTR1 and NTR2 mRNA were not detected in either pituitary adenomas or normal tissue. The higher expression of NTR3, as well as the expression of NT by tumoural corticotrophs, lactotrophs and somatotrophs, which are cells types that do not express this peptide in the normal pituitary, suggests that NT autocrine and/or paracrine stimulation mediated by NTR3 may be a mechanism associated with the tumourigenesis of functioning adenomas.
Assuntos
Adenoma/genética , Neurotensina/genética , Neoplasias Hipofisárias/genética , Receptores de Neurotensina/genética , Adenoma/metabolismo , Adenoma/patologia , Adulto , Idoso , Comunicação Autócrina/genética , Comunicação Autócrina/fisiologia , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Neurotensina/metabolismo , Comunicação Parácrina/genética , Comunicação Parácrina/fisiologia , Neoplasias Hipofisárias/metabolismo , Neoplasias Hipofisárias/patologia , RNA Mensageiro/metabolismo , Receptores de Neurotensina/metabolismo , Células Tumorais Cultivadas , Adulto JovemRESUMO
The purpose of the present study was the genetic characterization, sequencing and phylogenetic analysis of 18S rDNA sequences of Cryptosporidium isolates obtained from different animal hosts in Brazil. Fecal samples containing Cryptosporidium oocysts were obtained from chickens, ducks, quails, guinea pigs, dairy calves, dogs and cats. For amplification of 18S rDNA sequences the Secondary-PCR product of the extracted DNA from fecal suspension of each studied animal was utilized. The primary genetic characterization of Cryptosporidium sp. was performed using RFLP with the enzymes SspI and VspI. DNA samples were sequenced and subjected to phylogenetic analysis. The results showed C. baileyi infecting two ducks and one quail and C. melagridis infecting one chicken. The sequences obtained from Cryptosporidium sp. infecting guinea pigs were not identified within groups of known Cryptosporidium species. The isolates found parasitizing cats and one dog were diagnosed as C. felis and C. canis, respectively. One isolate of calf origin was identified as C. parvum. The phylogenetic analysis showed clear distribution of isolates between two Cryptosporidium sp. groups according to their gastric or intestinal parasitism. A great genetic distance was observed between C. felis and C. canis from Brazil when compared to the reference sequences obtained from GenBank. The results obtained during this study constitute the first report of rDNA sequences from C. baileyi, C. meleagridis, C. felis, C. canis and C. parvum isolated in Brazil.
Assuntos
Animais Domésticos/parasitologia , Cryptosporidium/classificação , Cryptosporidium/genética , Animais , Aves/parasitologia , Brasil , Criptosporidiose/parasitologia , Criptosporidiose/veterinária , Cryptosporidium/isolamento & purificação , DNA de Protozoário/genética , Fezes/parasitologia , Genótipo , Mamíferos/parasitologia , Dados de Sequência Molecular , FilogeniaRESUMO
INTRODUCTION: The frequent occurrence of prenatal hypertrophy of the muscular ventricular septum has been widely reported in fetuses of diabetic mothers. OBJECTIVES: This experimental study was carried out to test the hypothesis that the weight of the heart, the ratio of the cardiac weight to that of the body, the thickness of the muscular ventricular septum, and the myocytic profile within the ventricular septum are all increased in fetuses of diabetic rats in comparison to fetuses of normal rats. METHODS: Diabetes was induced in 5 pregnant Wistar rats, bearing 30 fetuses, on the eighth day after conception, by intraperitoneal injection of 50 mg/kg of streptozotocin. Five normal pregnant Wistar rats, bearing 20 fetuses, made up the control group. Morphometric data were obtained by a computer-assisted method applied to the measurements of the thickness of the ventricular septum, and myocytic nuclear area. Statistical analysis utilized Student's t-test and Kruskal-Wallis test. RESULTS: The mean thickness of the septum was 675.56 microm (+/-159) in the control fetuses, and 904.39 microm (+/-262) in the fetuses carried by diabetic mothers (p < 0.001). The cardiac weight was 0.016 g (+/-0.004) in the control group, and 0.023 g (+/-0.005) in the group of diabetic fetuses (p < 0.001). The ratio of cardiac to body weight was 0.294% (+/-0.079) in the control group, and 0.514% (+/-0.073) in the diabetic group (p < 0.001). The myocytic nuclear area was 14.70 microm2 in the control group, and 21.43 microm2 in the diabetic group (p < 0.001). CONCLUSIONS: The presence of cellular and morphologic cardiac hypertrophy in fetuses of diabetic rats was demonstrated by the significant difference between the two groups for each analyzed feature.
Assuntos
Cardiomegalia/etiologia , Diabetes Gestacional/complicações , Feto/anormalidades , Miocárdio/patologia , Animais , Glicemia/análise , Modelos Animais de Doenças , Feminino , Peso Fetal , Coração/crescimento & desenvolvimento , Fígado/crescimento & desenvolvimento , Modelos Cardiovasculares , Tamanho do Órgão , Gravidez , Gravidez em Diabéticas/complicações , Ratos , Ratos Wistar , Estatística como AssuntoRESUMO
The effect of Clinostomum detruncatum metacercaria infection on the activities of the antioxidant enzymes superoxide dismutase and catalase in muscle of the freshwater fish Rhamdia quelen was analyzed. Tert-butyl hydroperoxide-initiated chemiluminescence, a measure of lipid peroxidation, was also investigated. Enzyme activities were similar in infected and uninfected fishes. However, the chemiluminescence was almost 2-fold higher in muscle of infected fishes than in muscle of uninfected ones. These results indicate that parasite infection induces oxidative stress and a higher level of membrane damage in the fish muscle due to an imbalance between pro-oxidants and non-enzymatic antioxidants. Our results suggest that fish response to parasite infection could involve, as in other vertebrates, reactive oxygen intermediates.
Assuntos
Peixes-Gato , Doenças dos Peixes/parasitologia , Peroxidação de Lipídeos , Músculo Esquelético/parasitologia , Trematódeos/patogenicidade , Infecções por Trematódeos/veterinária , Animais , Brasil , Catalase/análise , Doenças dos Peixes/patologia , Medições Luminescentes , Músculo Esquelético/enzimologia , Músculo Esquelético/patologia , Estresse Oxidativo , Contagem de Cintilação/veterinária , Superóxido Dismutase/análise , Infecções por Trematódeos/parasitologia , Infecções por Trematódeos/patologia , terc-Butil Hidroperóxido/químicaRESUMO
The intestinal microbiota, a barrier to the establishment of pathogenic bacteria, is also an important reservoir of opportunistic pathogens. It plays a key role in the process of resistance-genes dissemination, commonly carried by specialized genetic elements, like plasmids, phages, and conjugative transposons. We obtained from strains of enterobacteria, isolated from faeces of newborns in a university hospital nursery, indication of phenotypical gentamicin resistance amplification (frequencies of 10(-3) to 10(-5), compatible with transposition frequencies). Southern blotting assays showed strong hybridization signals for both plasmidial and chromosomal regions in DNA extracted from variants selected at high gentamicin concentrations, using as a probe a labeled cloned insert containing aminoglycoside modifying enzyme (AME) gene sequence originated from a plasmid of a Klebsiella pneumoniae strain previously isolated in the same hospital. Further, we found indications of inactivation to other resistance genes in variants selected under similar conditions, as well as, indications of co-amplification of other AME markers (amikacin). Since the intestinal environment is a scenario of selective processes due to the therapeutic and prophylactic use of antimicrobial agents, the processes of amplification of low level antimicrobial resistance (not usually detected or sought by common methods used for antibiotic resistance surveillance) might compromise the effectiveness of antibiotic chemotherapy.
Assuntos
Fezes/microbiologia , Gentamicinas/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Resistência Microbiana a Medicamentos/genética , Amplificação de Genes , Hospitalização , Humanos , Recém-Nascido , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Células-TroncoRESUMO
A study was made on the development of cortical synapses in the gracile nucleus of rats using degeneration methods. A total of 46 animals, 1 adult and 45 neonates whose ages varied from 1 to 7 days, had the right somatosensory motor cortex destroyed. The survival period varied from 1 to 30 days. Identification of axonal terminals in the gracile nucleus was also achieved by tracing the cortical fibres of 1 adult rat using horseradish peroxidase-wheat germ agglutinin (HRP-WGA). Degenerating axodendritic and axosomatic terminals that originated from cortical fibres were seen in the adult animal which survived 2 days. Their origin was confirmed by the presence of HRP-WGA inside the terminals. Light or electron microscopic changes were not seen, and in particular, the gracile nucleus was not smaller than in the control adult animals which survived 30 days or in neonates which survived 8-30 days, consistent with the small component of cortifugal fibres believed to terminate in secondary sensory nuclei. In neonates that survived a shorter period, terminal degeneration was only seen in cases operated at 4 days and later, indicating that cortical axons do not synapse in the gracile nucleus until postnatal day 4. Our results provide further support for the existence of a period in which the fibres approach their target but do not penetrate it to form synaptic junctions during the growth of cortical axons toward their targets, since previous studies have demonstrated that cortical fibres persisting to adulthood decussate completely at the level of the medulla at 12-36 h after birth.(ABSTRACT TRUNCATED AT 250 WORDS)