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1.
Biomedica ; 44(1): 80-91, 2024 03 31.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-38648349

RESUMO

INTRODUCTION: The multifactorial etiology of gastroenteritis emphasizes the need for different laboratory methods to identify or exclude infectious agents and evaluate the severity of diarrheal disease. OBJECTIVE: To diagnose the infectious etiology in diarrheic children and to evaluate some fecal markers associated with intestinal integrity. MATERIALS AND METHODS: The study group comprised 45 children with diarrheal disease, tested for enteropathogens and malabsorption markers, and 76 children whose feces were used for fat evaluation by the traditional and acid steatocrit tests. RESULTS: We observed acute diarrhea in 80% of the children and persistent diarrhea in 20%. Of the diarrheic individuals analyzed, 40% were positive for enteropathogens, with rotavirus (13.3%) and Giardia duodenalis (11.1%) the most frequently diagnosed. Among the infected patients, occult blood was more evident in those carrying pathogenic bacteria (40%) and enteroviruses (40%), while steatorrhea was observed in infections by the protozoa G. duodenalis (35.7%). Children with diarrhea excreted significantly more lipids in feces than non-diarrheic children, as determined by the traditional (p<0.0003) and acid steatocrit (p<0.0001) methods. Moreover, the acid steatocrit method detected 16.7% more fecal fat than the traditional method. CONCLUSIONS: Childhood diarrhea can lead to increasingly severe nutrient deficiencies. Steatorrhea is the hallmark of malabsorption, and a stool test, such as the acid steatocrit, can be routinely used as a laboratory tool for the semi-quantitative evaluation of fat malabsorption in diarrheic children.


Introducción. La etiología multifactorial de la gastroenteritis enfatiza la necesidad de usar diferentes métodos de laboratorio para identificar o excluir agentes infecciosos y evaluar la gravedad de la enfermedad diarreica. Objetivo. Diagnosticar la etiología infecciosa de la diarrea en niños y evaluar algunos marcadores fecales asociados con la integridad intestinal. Materiales y métodos. Se estudiaron 45 niños con enfermedad diarreica, en los cuales se evaluaron la presencia de enteropatógenos y los marcadores de malabsorción. Se analizaron las muestras fecales de 76 niños, mediante las pruebas de esteatocrito tradicional y esteatocrito ácido, para la cuantificación de la grasa. Resultados. Se observó diarrea aguda en el 80 % de los niños y diarrea persistente en el 20 %. De los individuos con diarrea, el 40 % fue positivo para enteropatógenos; los más diagnosticados fueron rotavirus (13,3 %) y Giardia duodenalis (11,1 %). Entre los pacientes infectados, la sangre oculta fue más evidente en aquellos portadores de bacterias patógenas (40 %) o enterovirus (40%), mientras que la esteatorrea se observó en infecciones por el protozoo G. duodenalis (35,7 %). Los niños con diarrea excretaron significativamente más lípidos en las heces que aquellos sin diarrea, según lo determinado por los métodos de esteatocrito tradicional (p<0,0003) y esteatocrito ácido (p<0,0001). Conclusiones. La diarrea infantil puede provocar deficiencias graves de nutrientes. La esteatorrea es distintiva de la malabsorción intestinal y puede detectarse mediante la estimación del esteatocrito ácido. Esta prueba podría utilizarse de forma rutinaria como una herramienta de laboratorio para la evaluación semicuantitativa de la malabsorción de grasas en niños con diarrea.


Assuntos
Diarreia , Fezes , Síndromes de Malabsorção , Humanos , Diarreia/parasitologia , Diarreia/etiologia , Diarreia/microbiologia , Fezes/parasitologia , Pré-Escolar , Lactente , Síndromes de Malabsorção/complicações , Síndromes de Malabsorção/etiologia , Masculino , Feminino , Criança , Giardíase/complicações , Esteatorreia/etiologia , Gastroenterite/complicações , Gastroenterite/parasitologia , Gastroenterite/microbiologia , Sangue Oculto
2.
Braz J Infect Dis ; 28(1): 103705, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38065221

RESUMO

BACKGROUND: The COVID-19 pandemic has triggered crises in the public health sector that have complex and multifaceted interrelationships with antimicrobial resistance. It is important to evaluate the impact of COVID-19 on microbiological profile, antibiotic and alcohol gel consumption in Intensive Care Units (ICU). METHODS: This is a retrospective study undertaken in an infectious disease hospital located in Bahia/Brazil during three periods: from March 2019 to February 2020; from March 2020 to February 2021; and from March 2021 to February 2022. It was evaluated the incidence density of Candida spp and of multidrug-resistant Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species (ESKAPE group) in blood, urine and tracheal secretion isolated 48 h after the patient's admission to the ICU, as well as the use of alcohol gel (in milliliters) and consumption of antibiotics in Defined Daily Dose (DDD) per 1,000 ICU patient-days in the previous year and in the first two years of COVID-19 pandemic. RESULTS: There was an increase in Candida spp. (5.81, p < 0.001, IRR = 10.47, 95 % CI 2.57‒42.62) and in carbapenem-resistant A. baumannii in clinical cultures (4.71, p < 0.001, IRR = 8.46, 95 % CI 2.07‒34.60), the latter mainly in tracheal secretions (3.18, p= 0.02, IRR = 11.47, 95 % CI 1.58‒83.39). A rise in the consumption of ceftriaxone and piperacillin-tazobactam, along with an increase in the utilization of alcohol gel were observed. CONCLUSION: The shifting microbiological profile can be attributed to both the unique characteristics of patients with COVID-19 and the adjustments made to healthcare facilities' structural and work routines. Understanding these changes is essential in addressing the accelerated impact of antimicrobial resistance during the pandemic. Therefore, conducting thorough reviews of institutional practices and routines becomes critical in mitigating the consequences of antimicrobial resistance and its implications for patient care.


Assuntos
COVID-19 , Doenças Transmissíveis , Infecção Hospitalar , Humanos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Estudos Retrospectivos , Brasil/epidemiologia , Infecção Hospitalar/microbiologia , Pandemias , Doenças Transmissíveis/tratamento farmacológico , Hospitais , Unidades de Terapia Intensiva
3.
Braz. j. infect. dis ; 28(1): 103705, 2024. tab
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1550143

RESUMO

Abstract Background The COVID-19 pandemic has triggered crises in the public health sector that have complex and multifaceted interrelationships with antimicrobial resistance. It is important to evaluate the impact of COVID-19 on microbiological profile, antibiotic and alcohol gel consumption in Intensive Care Units (ICU). Methods This is a retrospective study undertaken in an infectious disease hospital located in Bahia/Brazil during three periods: from March 2019 to February 2020; from March 2020 to February 2021; and from March 2021 to February 2022. It was evaluated the incidence density of Candida spp and of multidrug-resistant Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species (ESKAPE group) in blood, urine and tracheal secretion isolated 48 h after the patient's admission to the ICU, as well as the use of alcohol gel (in milliliters) and consumption of antibiotics in Defined Daily Dose (DDD) per 1,000 ICU patient-days in the previous year and in the first two years of COVID-19 pandemic. Results There was an increase in Candida spp. (5.81, p < 0.001, IRR = 10.47, 95 % CI 2.57‒42.62) and in carbapenem-resistant A. baumannii in clinical cultures (4.71, p < 0.001, IRR = 8.46, 95 % CI 2.07‒34.60), the latter mainly in tracheal secretions (3.18, p =0.02, IRR = 11.47, 95 % CI 1.58‒83.39). A rise in the consumption of ceftriaxone and piperacillin-tazobactam, along with an increase in the utilization of alcohol gel were observed. Conclusion The shifting microbiological profile can be attributed to both the unique characteristics of patients with COVID-19 and the adjustments made to healthcare facilities' structural and work routines. Understanding these changes is essential in addressing the accelerated impact of antimicrobial resistance during the pandemic. Therefore, conducting thorough reviews of institutional practices and routines becomes critical in mitigating the consequences of antimicrobial resistance and its implications for patient care.

4.
Fitoterapia ; 168: 105489, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36990289

RESUMO

Rutaceae is a family expressed by approximately 2100 species distributed in 154 genera widespread in tropical and temperate regions of Australasia, America, and South Africa. Substantial species of this family are employed as folk medicines. The literature describes the Rutaceae family as a great source of natural and bioactive compounds like terpenoids, flavonoids, and, especially, coumarins. To data, 655 coumarins were isolated and identified from Rutaceae in the past twelve years and, most of them, showed different biological and pharmacological activities. There are studies with coumarins from Rutaceae indicating that these compounds showed activity against cancer, inflammation, infectious diseases, and in the treatment of endocrinal and gastrointestinal conditions. Although coumarins are considered versatile bioactive molecules, until the present, there is no compiled information about coumarins from the Rutaceae family demonstrating the potency of these compounds in all dimensions and chemical similarities among the genera. The present review covers the relevant studies dealing with isolation of Rutaceae coumarins from 2010 until 2022 and outlines the current data on pharmacological activities these coumpounds. Additionally, the chemical disposition and similarity among Rutaceae genera are also statistically discussed employing PCA and HCA methods.


Assuntos
Cumarínicos , Rutaceae , Rutaceae/química , Estrutura Molecular , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Flavonoides
5.
Braz J Microbiol ; 54(1): 37-52, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36576671

RESUMO

Biofilms are communities of microbial cells surrounded by an extracellular polysaccharide matrix, recognized as a fungal source for local and systemic infections and less susceptible to antifungal drugs. Thus, treatment of biofilm-related Candida spp. infections with popular antifungals such as fluconazole is limited and species-dependent and alternatively demands the use of expensive and high toxic drugs. In this sense, molecules with antibiofilm activity have been studied but without care regarding the use of important criteria such as antibiofilm concentration lower than antifungal concentration when considering the process of inhibition of formation and concentrations equal to or lower than 300 µM. Therefore, this review tries to gather the most promising molecules regarding the activity against the C. albicans biofilm described in the last 10 years, considering the activity of inhibition and eradication. From January 2011 to July 2021, articles were searched on Scopus, PubMed, and Science Direct, combining the keywords "antibiofilm," "candida albicans," "compound," and "molecule" with AND and OR operators. After 3 phases of selection, 21 articles describing 42 molecules were discussed in the review. Most of them were more promising for the inhibition of biofilm formation, with SM21 (24) being an interesting molecule for presenting inhibitory and eradication activity in biofilms with 24 and 48 h, as well as alizarin (26) and chrysazine (27), with concentrations well below the antifungal concentration. Despite the detection of these molecules and the attempts to determine the mechanisms of action by microscopic analysis and gene expression, no specific target has been determined. Thus, a gap is signaled, requiring further studies such as proteomic analyses to clarify it.


Assuntos
Candida albicans , Candidíase , Antifúngicos/farmacologia , Proteômica , Fluconazol/farmacologia , Candidíase/microbiologia , Biofilmes , Testes de Sensibilidade Microbiana
6.
Front Cell Infect Microbiol ; 11: 642658, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34277464

RESUMO

Cryptococcosis is an infectious disease of worldwide distribution, caused by encapsulated yeasts belonging to the phylum Basidiomycota. The genus Cryptococcus includes several species distributed around the world. The C. gattii/neoformans species complex is largely responsible for most cases of cryptococcosis. However, clinical series have been published of infections caused by Papiliotrema (Cryptococcus) laurentii and Naganishia albida (Cryptococcus albidus), among other related genera. Here, we examined the pathogenic potential and antifungal susceptibility of C. gattii/neoformans species complex (clades I and II) and related genera (Papiliotrema and Naganishia) isolated from environmental and clinical samples. P. laurentii (clade III), N. liquefasciens/N. albidosimilis (clade IV); and N. adeliensis/N. albida (clade V) strains produced higher levels of phospholipase and hemolysins, whereas the C. gattii/neoformans species complex strains (clades I and II) had markedly thicker capsules, produced more biofilm biomass and melanin, which are known virulence attributes. Interestingly, 40% of C. neoformans strains (clade II) had MICs above the ECV established for this species to amphotericin B. Several non-C. gattii/neoformans species complex (clades III to V) had MICs equal to or above the ECVs established for C. deuterogattii and C. neoformans for all the three antifungal drugs tested. Finally, all the non-C. gattii/neoformans clinical isolates (clades III to V) produced more melanin than the environmental isolates might reflect their particularly enhanced need for melanin during in vivo protection. It is very clear that C. gattii/neoformans species complex (clades I and II) strains, in general, show more similar virulence phenotypes between each other when compared to non-C. gattii/neoformans species complex (clades III to V) isolates. These observations together with the fact that P. laurentii and Naganishia spp. (clades III to V) strains were collected from the outside of a University Hospital, identify features of these yeasts important for environmental and patient colonization and furthermore, define mechanisms for infections with these uncommon pathogens.


Assuntos
Basidiomycota , Cryptococcus gattii , Cryptococcus neoformans , Antifúngicos/farmacologia , Humanos , Virulência , Fatores de Virulência
7.
Mol Biol Rep ; 46(6): 6147-6154, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31602591

RESUMO

Candida albicans infection development depends on several factors associated with this etiological agent, including secreted aspartyl protease (Sap) production. Sap expression commonly occurs under selective pressure caused by the presence of antifungals. Fluconazole is the main antifungal drug used for treatment or prophylaxis. This study investigated the influence of inhibitory and sub-inhibitory fluconazole concentrations on Sap activity and their gene transcription for three clinical C. albicans isolates. Two isolates presented significant increases in Sap activity and transcription of SAP 1-8 genes in the presence of 1 MIC80 of fluconazole compared to the absence of the antifungal agent. The results suggest that the increase in Sap activity occurs due to an upregulation of the SAP gene transcription influenced by fluconazole. This suggests the importance of all SAP genes in the progression of bloodstream infections compared to primary tissue infection. However, this phenomenon does not occur everywhere, and it is multifactorial. This may be related to the selective pressure effect on transcription modulators. Although preliminary, these results open a new perspective for the study of virulence factors.


Assuntos
Ácido Aspártico Proteases/genética , Candida albicans/efeitos dos fármacos , Candida albicans/genética , Candidíase/microbiologia , Fluconazol/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Candida albicans/isolamento & purificação , Candidíase/tratamento farmacológico , Ativação Enzimática , Humanos , Testes de Sensibilidade Microbiana
8.
Med Mycol ; 54(1): 89-96, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26392390

RESUMO

In this work, two accurate and sensitive real-time polymerase chain reaction (PCR) assays to differentiate pathogenic Cryptococcus gattii sensu lato (s.l.) and C. neoformans sensu lato (s.l.) targeting the intergenic spacer 1 (IGS1) region from rDNA locus were developed. Specific primers were designed based on their IGS1 sequence analyses and the optimal real-time PCR assays showed that the dissociation curves generated two different melting peaks, at 82.8 and 84.2ºC for C. gattii s.l. and C. neoformans s.l., respectively. No amplifications were observed in the negative template control. The minimum limit of detection of both primers was 100 plasmid copies per reaction, and they were highly specific when tested with a range of fungal DNAs. Overall, the results showed that the designed primers completely differentiated C. gattii s.l. and C. neoformans s.l. from clinical and environmental sources with great accuracy when compared to phenotypic identification, with no cross-reactivity to other fungal DNA.


Assuntos
Cryptococcus gattii/classificação , Cryptococcus neoformans/classificação , DNA Espaçador Ribossômico/genética , Técnicas Microbiológicas/métodos , Técnicas de Diagnóstico Molecular/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Cryptococcus gattii/genética , Cryptococcus neoformans/genética , Primers do DNA/genética , DNA Fúngico/genética , Humanos , Sensibilidade e Especificidade , Temperatura de Transição
9.
Braz J Infect Dis ; 18(2): 215-9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24275368

RESUMO

Lower airway infection is a major cause of morbidity and mortality in patients with cystic fibrosis. It is currently unknown if the infection of the upper airway can cause exacerbation of lower respiratory tract infection. This study aimed to determine the microbiological profile of the anterior paranasal sinuses outflow tract (middle meatus) of cystic fibrosis outpatients. The microbiological profile was defined using endoscopically directed middle meatal cultures. Paired middle meatal and sputum specimens were collected from 56 outpatients for aerobic cultures. A semi-quantitative leukocyte count of the middle meatal samples was performed. The median age of patients was nine years (3-20 years). Staphylococcus aureus (37%), Staphylococcus coagulase-negative (25%), Neisseriac (14%), Pseudomonas aeruginosa (11%), and Streptococcus pneumoniae (7%) were the most prevalent microorganisms in the middle meatal cultures. Using the middle meatal leukocyte count, 16 out of 54 patients (29.6%) presented sinus infection. The most frequently identified pathogens in patients with sinus infections were Staphylococcus aureus (10 patients), Pseudomonas aeruginosa (4 patients), and Streptococcus pneumoniae (3 patients). Agreement of paired middle meatal and sputum cultures was significantly higher among patients with infection in middle meatal (69%). The most common middle meatal pathogens were the typical cystic fibrosis spectrum. This suggests the potential for participating in post-nasal lower airway seeding.


Assuntos
Fibrose Cística/microbiologia , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/isolamento & purificação , Seios Paranasais/microbiologia , Escarro/microbiologia , Adolescente , Brasil , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Estudos Prospectivos , Adulto Jovem
10.
Braz J Infect Dis ; 14(4): 406-9, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20963328

RESUMO

Respiratory infection is very common in patients suffering from cystic fibrosis (CF). However, the antimicrobial resistance rate of isolates from CF patients is not often documented. In this study, 279 respiratory specimens of 146 patients were prospectively collected from July to December 2006. Microbiological cultures and antimicrobial susceptibility tests of the most frequently isolated bacteria were performed. Sputum and oropharyngeal swabs were processed for culture. During the study period, 50% of the patients harbored Staphylococcus aureus, 35% Pseudomonas aeruginosa, 4.7% Haemophilus influenzae. Methicillin resistant S. aureus (MRSA) were detected in 8 (6%) patients; ESBL and MBL-producing P. aeruginosa were not identified in these patients. The detection of MRSA in CF patients confirms that antimicrobial resistance patterns should be always kept under surveillance. Moreover, hygiene regulations in CF clinics should prevent a further spread of resistant bacterial strains.


Assuntos
Antibacterianos/farmacologia , Fibrose Cística/microbiologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Orofaringe/microbiologia , Escarro/microbiologia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/isolamento & purificação , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Prevalência , Estudos Prospectivos , Adulto Jovem
11.
Braz. j. infect. dis ; 14(4): 406-409, July-Aug. 2010. tab
Artigo em Inglês | LILACS | ID: lil-561215

RESUMO

Respiratory infection is very common in patients suffering from cystic fibrosis (CF). However, the antimicrobial resistance rate of isolates from CF patients is not often documented. In this study, 279 respiratory specimens of 146 patients were prospectively collected from July to December 2006. Microbiological cultures and antimicrobial susceptibility tests of the most frequently isolated bacteria were performed. Sputum and oropharyngeal swabs were processed for culture. During the study period, 50 percent of the patients harbored Staphylococcus aureus, 35 percent Pseudomonas aeruginosa, 4.7 percent Haemophilus influenzae. Methicillin resistant S. aureus (MRSA) were detected in 8 (6 percent) patients; ESBL and MBL-producing P. aeruginosa were not identified in these patients. The detection of MRSA in CF patients confirms that antimicrobial resistance patterns should be always kept under surveillance. Moreover, hygiene regulations in CF clinics should prevent a further spread of resistant bacterial strains.


Assuntos
Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Antibacterianos/farmacologia , Fibrose Cística/microbiologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Orofaringe/microbiologia , Escarro/microbiologia , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/isolamento & purificação , Testes de Sensibilidade Microbiana , Prevalência , Estudos Prospectivos , Adulto Jovem
12.
Säo Paulo; s.n; 2001. [120] p. ilus, tab.
Tese em Português | LILACS | ID: lil-308504

RESUMO

Um gene homólogo ao LON do patógeno humano Paracoccidioides brasiliensis (PbLON) foi clonado, sequenciado e caracterizado (AF239178). O gene codifica para uma proteinase Lon ATP-dependente putativa, que em Saccharomyces cerevisiae é uma proteína induzida pelo calor envolvida na degradaçao de proteínas anormais ou de vida curta da matriz mitocondrial. A fase aberta de leitura (ORF) do PbLON está contida em um fragmento de 3369 bp interrompido por dois introns localizados no segmento C-terminal. As regioes 5' e 3' flanqueando a ORF contém sequências que se assemelham a elementos de início e final de transcriçao. Vários motivos de ligaçao de fatores de transcriçao também foram observados, incluindo HSE e STRE-like, relacionados à resposta de estresse ou de choque térmico, e NIT2, relacionado ao controle do metabolismo de nitrogênio. A proteína deduzida de PbLON consiste em 1063 resíduos de aminoácidos que contém um sinal putativo de importe mitocondrial no N-terminal e regioes conservadas do sítio de ligaçao de ATP (GPPGVGKT) e sítio da serina catalítica (KDGPSAG). A seqüência apresenta alta similaridade com proteínas homólogas de S. cerevisiae, Homo sapiens e Escherichia coli, estando filogeneticamente mais próxima à de levedura. Em P. brasiliensis, um gene homólogo ao MDJ1 (GenBank AF334811) foi encontrado adjacente ao PbLON e parcialmente sequenciado. Os genes possuem uma regiao 5' intergênica comum e possivelmente compartilham elementos de promotor e de transcriçao opostamente orientados. Esta organizaçao cromosomal é interessante, pois Mdj1 p é um chaperone de choque térmico da matriz mitocondrial, e é essencial para degradaçao de substratos desnaturados pela Lon em S. cerevisiae. O mapeamento cromossômico dos homólogos PbLON e PbMDJ1 em P. brasiliensis mostrou que esses genes estao ligados em 12 isolados estudados, mapeando geralmente em uma banda de 10Mb. Através de Southern blot de 13 outros isolados, foi possível distinguir três com um polimorfismo numa regiao 3' do PbLON. Esses genes sao aparentemente de cópia única, sendo que um transcrito de -3,5 kb foi observado para PbLON e outro de -2,5 kb para PbMDJ1. Aparentemente, ambos foram mais expressos após 30 min de choque térmico a 42ºC, como verificado por Northern blot. A presença de mRNA do PbLON foi detectada através de RT-PCR tanto da fase miceliana quanto leveduriforme do fungo. A obtençao da Lon recombinante de P. brasiliensis está em andamento


Assuntos
Paracoccidioides , Proteínas de Choque Térmico
13.
Säo Paulo; s.n; 2001. [120] p. ilus, tab.
Tese em Português | LILACS | ID: lil-297261

RESUMO

Um gene homólogo ao LON do patógeno humano Paracoccidioides brasiliensis (PbLON) foi clonado, sequenciado e caracterizado (AF239178). O gene codifica para uma proteinase Lon ATP-dependente putativa, que em Saccharomyces cerevisiae é uma proteína induzida pelo calor envolvida na degradaçao de proteínas anormais ou de vida curta da matriz mitocondrial. A fase aberta de leitura (ORF) do PbLON está contida em um fragmento de 3369 bp interrompido por dois introns localizados no segmento C-terminal. As regioes 5' e 3' flanqueando a ORF contêm sequências que se assemelham a elementos de início e final de transcriçao. Vários motivos de ligaçao de fatores de transcriçao também foram observados, incluindo HSE e STRE-like, relacionados à resposta de estresse ou de choque térmico, e NIT2, relacionado ao controle do metabolismo de nitrogênio. A proteína deduzida de PbLON consiste em 1063 resíduos de aminoácidos que contêm um sinal putativo de importe mitocondrial no N-terminal e regioes conservadas do sítio de ligaçao de ATP (GPPGVGKT) e sítio da serina catalítica (KDGPSAG). A seqüência apresenta alta similaridade com proteínas homólogas de S. cerevisiae, Homo sapiens e Escherichia coli, estando filogeneticamente mais próxima à de levedura. Em P. brasiliensis, um gene homólogo ao MDJ1 (GenBank AF334811) foi encontrado adjacente ao PbLON e parcialmente sequenciado. Os genes possuem uma regiao 5' intergênica comum e possivelmente compartilham elementos de promotor e de transcriçao opostamente orientados. Esta organizaçao cromosomal é interessante, pois Mdj1 p é um chaperone de choque térmico da matriz mitocondrial, e é essencial para degradaçao de substratos desnaturados pela Lon em S. cerevisiae. O mapeamento cromossômico dos homólogos PbLON e PbMDJ1 em P. brasiliensis mostrou que esses genes estao ligados em 12 isolados estudados, mapeando geralmente em uma banda de 10Mb. Através de Southern blot de 13 outros isolados, foi possível distinguir três com um polimorfismo numa regiao 3' do PbLON. Esses genes sao aparentemente de cópia única, sendo que um transcrito de -3,5 kb foi observado para PbLON e outro de -2,5 kb para PbMDJ1. Aparentemente, ambos foram mais expressos após 30 min de choque térmico a 42ºC, como verificado por Northem blot. A presença de mRNA do PbLON foi detectada através de RT-PCR tanto da fase miceliana quanto leveduriforme do fungo. A obtençao da Lon recombinante de P. brasiliensis está em andamento.


Assuntos
Paracoccidioides , Proteínas de Choque Térmico
14.
Rev. Inst. Med. Trop. Säo Paulo ; 41(6): 343-350, Nov.-Dec. 1999.
Artigo em Inglês | LILACS | ID: lil-320656

RESUMO

Antigenic preparations (saline, methylic, metabolic and exoantigens) of four agents of chromoblastomycosis, Fonsecaea pedrosoi, Phialophora verrucosa, Cladophialophora (Cladosporium) carrionii and Rhinocladiella aquaspersa were obtained. Partial chemical characterization of these antigenic preparations was obtained by determination of the levels of total lipids, protein, and carbohydrates, and identification of the main sterols and carbohydrates. Methylic antigens presented the highest lipid contents, whereas metabolic antigens showed the highest carbohydrate content. Total lipid, protein, and carbohydrate levels were in the range of 2.33 to 2.00 mg/ml, 0.04 to 0.02 mg/ml and 0.10 to 0.02 mg/ml, respectively, in the methylic antigens and in the range of 0. 53 to 0.18 mg/ml, 0.44 to 0.26 mg/ml, and 1.82 to 1.02 mg/ml, respectively, in saline antigens. Total lipid, protein, and carbohydrate contents were in the range of 0.55 to 0.20 mg/ml, 0.69 to 0.57 mg/ml and 10.73 to 5.93 mg/ml, respectively, in the metabolic antigens, and in the range of 0.55 to 0.15 mg/ml, 0.62 to 0.20 mg/ml and 3.55 to 0.42 mg/ml, respectively, in the exoantigens. Phospholipids were not detected in the preparations. Saline and metabolic antigens and exoantigens presented hexose and the methylic antigen revealed additional pentose units in their composition. The UV light absorption spectra of the sterols revealed squalene and an ergosterol fraction in the antigens. The characterization of these antigenic preparations may be useful for serological evaluation of patients of chromoblastomycosis.


Assuntos
Antígenos de Fungos/química , Carboidratos , Cromoblastomicose , Fungos Mitospóricos/imunologia , Lipídeos/análise , Proteínas de Bactérias/análise , Esteróis/análise
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