RESUMO
Re-emergence of vector-borne diseases such as dengue and yellow fever, which are both transmitted by the Aedes aegypti mosquito, has been correlated with insecticide resistance. P-glycoproteins (P-gps) are ATP-dependent efflux pumps that are involved in the transport of substrates across membranes. Some of these proteins have been implicated in multidrug resistance (MDR). In this study, we identified a putative P-glycoprotein in the Ae. aegypti database based on its significantly high identity with Anopheles gambiae, Culex quinquefasciatus, Drosophila melanogaster and human P-gps. The basal ATPase activity of ATP-binding cassette transporters in larvae was significantly increased in the presence of MDR modulators (verapamil and quinidine). An eightfold increase in Ae. aegypti P-gp (AaegP-gp) gene expression was detected in temephos-treated larvae as determined by quantitative PCR. To analyse the potential role of AaegP-gp in insecticide efflux, a temephos larvicide assay was performed in the presence of verapamil. The results showed an increase of 24% in temephos toxicity, which is in agreement with the efflux reversing effect. RNA interference (RNAi)-mediated silencing of the AaegP-gp gene caused a significant increase in temephos toxicity (57%). In conclusion, we have demonstrated for the first time in insects that insecticide-induced P-gp expression can be involved in the modulation of insecticide efflux.
Assuntos
Aedes/efeitos dos fármacos , Larva/efeitos dos fármacos , Temefós , Subfamília B de Transportador de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/metabolismo , Sequência de Aminoácidos , Animais , Expressão Gênica/efeitos dos fármacos , Resistência a Inseticidas/genética , Dados de Sequência Molecular , Mortalidade , Quinidina/farmacologia , Verapamil/farmacologiaRESUMO
The estimation of biomass is an essential parameter for controlling fermentation processes. However, monitoring biomass growth in filamentous fungi solid-state fermentation is laborious. The aim of this study was to provide a better insight into the monitoring of biomass growth in Aspergillus niger 3T5B8 solid-state fermentation using a digital image-processing technique. The images were acquired with a stereomicroscope and a digital camera, and processed using KS400 software. Growth was evaluated every 24 h for 5 days, and quantified as the total area occupied by the hyphae. The correlation between the results of the proposed methodology and the polygalacturonase data was greater than 0.9, showing that a direct and linear relationship can be expected among these parameters. This work indicates that the digital processing technique can be used for indirect biomass estimation in a solid-state fermentation process.
Assuntos
Aspergillus niger/crescimento & desenvolvimento , Biomassa , Fermentação , Monitorização Fisiológica/métodos , Biotecnologia/métodos , Meios de CulturaRESUMO
All proteins involved in the attachment and effacement lesion produced by enteropathogenic Escherichia coli (EPEC) and Shiga-toxin producing E. coli (STEC) are encoded by the locus of enterocyte effacement (LEE). We studied the presence and insertion site of the LEE in different EPEC and STEC strains. In serotypes O119:H6/H-, O55:H6, O55:H7, O142:H6, O111ac:H9/H-, O111ab:H9/H- LEE is inserted downstream of selC as previously described for EPEC O127:H6 and STEC O157:H7. In serotypes O111ac:H8/H- and O26:H11/H- the LEE is inserted in pheU as previously described for STEC O26:H-. However in EPEC from serotype O111ab:H25 the LEE is not inserted in either site suggesting a third insertion site in the K12 chromosome. We also cloned fragments of 2.3 kb and 1.0 kb from the right and left hand sides of the LEE of a O111ac:H- strain and identified additional insertion sequences on these LEE fragments, suggesting that the LEE may be larger and may have undergone more recombination events in these serotypes.
Assuntos
Aderência Bacteriana/genética , Proteínas de Bactérias/genética , DNA Bacteriano/genética , Escherichia coli/genética , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Escherichia coli/química , Humanos , Reação em Cadeia da Polimerase , Toxinas ShigaRESUMO
Foram avaliados os sorotipos de 5.490 cepas de Salmonella isolados no periodo, 1991-95, de infeccoes humanas (2.254 cepas) e de materiais de origem nao humana (3.236 cepas) bem como o perfil de sensibilidade aos agentes antimicrobianos de 131 cepas de S. enteritidis (92 de origem humana e 39 de origem nao humana). No periodo estudado, foram determinados 81 diferentes sorotipos. S. Enteritidis correspondeu a 1,2 por cento em 1991, 2 por cento em 1992, 10,1 por cento em 1993, 43,3 por cento em 1994 e 64,9 por cento em 1995. Um aumento significativo no isolamento de S. enteritidis foi verificado em 1993 associado a ocorrencia de surtos de enfermidades transmitidas por alimentos. E relatado tambem o aumento deste sorotipo a partir de hemoculturas, principalmente daquelas oriundas de pacientes com sindrome de imunodeficiencia. S. enteritidis foi tambem o sorotipo prevalente em materiais de origem nao humana, particularmente em ovos, aves (matrizes) e em amostras do meio ambiente. Ressalta-se a importancia da contaminacao, das materias primas, componentes de racao de aves, pela S. enteritidis, o que representa um preocupante problema para a avicultura brasileira
Assuntos
Humanos , Infecções por Salmonella/epidemiologia , Salmonella enteritidis/isolamento & purificação , Sorotipagem , Brasil , Testes de Sensibilidade Microbiana , Estudos RetrospectivosRESUMO
Serovars of a total of 5,490 Salmonella strains isolated during the period of 1991-95, from human infections (2,254 strains) and from non-human materials (3,236 strains) were evaluated. In the studied period, 81 different serovars were determined among human isolates. Salmonella Enteritidis corresponded to 1.2% in 1991, 2% in 1992, 10.1% in 1993, 43.3% in 1994, and 64.9% in 1995 of all isolates. A significant rise on the isolation of this serovar was seen since 1993 linked to food poisoning outbreaks. It is reported also an increase on the isolation of S. Enteritidis from blood cultures, associated mainly with patients with immunodeficiency syndrome. S. Enteritidis was prevalent among one hundred and thirty different serovars isolated from non-human sources. Increasing number of isolation of this serovar was seen from shell eggs, breeding flocks and from environmental samples. It is also reported a contamination of commercial feed stuffs by S. Enteritidis which represents a major concern for Brazilian poultry industry.
Assuntos
Infecções por Salmonella/epidemiologia , Salmonella/isolamento & purificação , Animais , Brasil/epidemiologia , Resistência Microbiana a Medicamentos , Microbiologia Ambiental , Contaminação de Alimentos , Humanos , Prevalência , Estudos Retrospectivos , Salmonella/classificação , Infecções por Salmonella/microbiologia , Salmonella enteritidis/isolamento & purificação , SorotipagemRESUMO
A total of 574 S. Enteritidis strains (383 from human sources and 191 from non-human sources) isolated between 1975-95, in São Paulo State, Brazil, were phagetyped. Among the strains isolated during the period of 1975-92, 80.9 of them belonged to phage type 8 (PT-8), but in 1993 strains of PT-4 accounted for 65.2 of all the S. Enteritidis isolates. In the following years, PT-4 strains accounted for 99.7 and 98.4 of phagetyped S. Enteritidis strains. The results obtained suggested that the current epidemic of S. Enteritidis in São Paulo State is clearly associated with the progression of PT-4 strains.
Assuntos
Humanos , Tipagem de Bacteriófagos , Salmonella enteritidis , Brasil , Salmonella enteritidisRESUMO
A total of 574 S. Enteritidis strains (383 from human sources and 191 from non-human sources) isolated between 1975-95, in São Paulo State, Brazil, were phagetyped. Among the strains isolated during the period of 1975-92, 80.9% of them belonged to phage type 8 (PT-8), but in 1993 strains of PT-4 accounted for 65.2% of all the S. Enteritidis isolates. In the following years, PT-4 strains accounted for 99.7% and 98.4% of phagetyped S. Enteritidis strains. The results obtained suggested that the current epidemic of S. Enteritidis in São Paulo State is clearly associated with the progression of PT-4 strains.
Assuntos
Tipagem de Bacteriófagos , Salmonella enteritidis/classificação , Bacteriófago T4 , Brasil , Humanos , Salmonella enteritidis/isolamento & purificaçãoRESUMO
No periodo de 1950-90 foram identificadas 45.862 cepas de Salmonella, sendo 31.517 provenientes de infeccoes humanas e 14.345 de materiais de origem nao humana. O objetivo deste trabalho foi analisar as alteracoes ocorridas quanto a frequencia dos sorotipos isolados neste periodo. No periodo 1950-66, nao houve predominio evidente de nenhum sorotipo; entretanto, no perido 1970-76, com inicio em 1968, a S. Typhimurium passou a ser o sorotipo predominante, representando 77,7 por cento dos sorotipos isolados. Observou-se um aumento significativo da S. Agona, bem como de uma grande variedade de sorotipos. Quanto as salmonelas de origem nao humana, chama a atencao o grande numero (mais de 100) de sorotipos...
Assuntos
Infecções por Salmonella/epidemiologia , Serviços Laboratoriais de Saúde Pública , Infecções por Salmonella/classificação , Salmonella/isolamento & purificação , SorotipagemRESUMO
From 1950 to 1990 a total of 45,862 strains (31,517 isolates from human sources, and 14,345 of non-human origin) were identified at Instituto Adolfo Lutz. No prevalence of any serovars was seen during the period 1950-66 among human sources isolates. Important changing pattern was seen in 1968, when S. Typhimurium surprisingly increased becoming the prevalent serovar in the following decades. During the period of 1970-76, S. Typhimurium represented 77.7% of all serovar of human origin. Significant rise in S. Agona isolation as well as in the number of different serovars among human sources strains were seen in the late 70' and the 80's. More than one hundred different serovars were identified among non-human origin strains. Among serovars isolated from human sources, 74.9%, 15.5%, and 3.7% were recovered from stool, blood, and cerebrospinal fluid cultures, respectively. The outbreak of meningitis by S. Grumpensis in the 60's, emphasizes the concept that any Salmonella serovars can be a cause of epidemics, mainly of the nosocomial origin. This evaluation covering a long period shows the important role of the Public Health Laboratory in the surveillance of salmonellosis, one of the most frequent zoonosis in the world.
Assuntos
Laboratórios , Infecções por Salmonella/epidemiologia , Salmonella/isolamento & purificação , Brasil/epidemiologia , Humanos , Incidência , Saúde Pública , Estudos Retrospectivos , Salmonella/classificação , SorotipagemRESUMO
The molecular method of ribotyping was used as an additional epidemiological marker to study the epidemic strains of Neisseria meningitidis serogroup B, referred to as the ET-5 complex, responsible for the epidemic which occurred in greater São Paulo, Brazil. Ribotyping analysis of these strains showed only a single rRNA gene restriction pattern (Rb1), obtained with ClaI restriction enzyme. This method, as well as multilocus enzyme electrophoresis, provided useful information about the clonal characteristics of the N. meningitidis serogroup B strains isolated during this epidemic. The N. meningitidis serogroup B isolates obtained from epidemics which occurred in Norway, Chile, and Cuba also demonstrated the same pattern (Rb1). Ribotyping was a procedure which could be applied to a large number of isolates and was felt to be appropriate for routine use in laboratories, especially because of the convenience of using nonradioactive probes.