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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

A bench-scale examination of the effect of static mixers on the disinfection of cryptosporidium parvum

Heindel, Heather Lee 12 1900 (has links)
No description available.
12

Developing Lab on a Chip Technology for the Detection and Characterisation of Giardia duodenalis cysts and Cryptosporidium spp. oocysts on Foods

Ganz, Kyle January 2015 (has links)
In the present study methods which can be integrated into a complete lab on a chip system for the detection and characterisation of Giardia duodenalis cysts and Cryptosporidium spp. oocysts from foods were developed and tested. Microfluidic chips, which make use of inertial separation, were designed and fabricated for the concentration and separation of either cysts or oocysts from food particles. These chips were highly specific for their intended target and were shown to be effective when used for artificially contaminated lettuce samples. The quantification by real-time PCR of Cryptosporidium spp. hsp70 mRNA, expressed in response to a heat stress, was assessed as a potential lab on a chip method for the detection of viable oocysts from foods. This method proved to be effective in determining the viability of oocysts in apple cider and the effects of high hydrostatic pressures on the viability of oocysts.
13

Ocorrência e caracterização molecular de Cryptosporidium spp. em cordeiros na Região de Araçatuba-SP-Brasil: avaliação da transferência da imunidade passiva

Féres, Flávia Corbari [UNESP] 18 April 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:25:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-04-18Bitstream added on 2014-06-13T20:14:20Z : No. of bitstreams: 1 feres_fc_me_araca.pdf: 219812 bytes, checksum: 1f1fed7d532991a23b940dd724388339 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Foram coletadas 460 amostras de fezes de cordeiros com até 30 dias de vida com o objetivo de determinar a ocorrência de Cryptosporidium na região de Araçatuba, assim como as espécies envolvidas nesta parasitose. Realizou-se análise microscópica pela técnica de coloração negativa com verde malaquita em todas as amostras de fezes. Para a identificação molecular de Cryptosporidium, nas amostras positivas à microscopia, utilizou-se a reação de nested PCR, com amplificação de fragmentos da subunidade 18S do gene do RNA ribossômico ou do gene da actina. Encontraram-se 6,73% dos animais eliminando oocistos de Cryptosporidium nas fezes. A espécie e genótipo envolvidos foram: Cryptosporidium parvum e genótipo cervídeo que representam potencial zoonótico e Cryptosporidium parvum tipo B. Foram coletadas também 191 amostras de sangue de cordeiros com até 30 dias de vida com o objetivo de determinar as concentrações séricas de imunoglobulina G, PT, γ globulina, GGT e FA, assim como determinar a associação entre estas variáveis. Foi avaliada se a atividade sérica das enzimas GGT e FA pode ser utilizada indiretamente como indicadora de transferência de imunidade passiva. Para tanto, foram realizados os testes de imunodifusão radial, espectrofotometria e eletroforese respectivamente. Para os valores de GGT e FA, foram utilizados kits comerciais. Houve correlação estatística significativa entre a FA e GGT; fato também observado com relação a PT, a IgG e a GGT. A γ globulina mostrou-se correlacionada com GGT, IgG e PT. A atividade de FA demonstrou-se ineficaz para uso como indicadora de transferência de imunidade passiva. / A total of 460 fecal samples were collected from lambs during the first 30 days of life with the aim to determine the occurrence of Cryptosporidium in Araçatuba region, as well as to identify species involved in this parasitism. Microscopic analysis of feces was carried out using malachite green negative stain. Cryptosporidium positive samples were subjective to a nested PCR, with amplification of fragments of the subunity 18S of the gene of the ribossomic RNA or the gene of the actin. In this study 6.73% of animals were eliminating oocists of Cryptosporidium in their feces. The involved species and genotype were: Cryptosporidium parvum and cervide genotype, which represent a zoonotic potential and Cryptosporidium parvum type B. Blood samples (191) were collected from lambs that were up to 30 days old to determine the serum concentrations of immunoglobulin G, TP, γ globulin, GGT and ALP, as well as to determine the association between these variables. This was done in order to explore the possibility of using changes in activities of GGT e ALP as indirect indicators of immune passive transfer in lambs The following tests were perfomed: radial immunodiffusion, spectrophotometry and electrophoresis respectively. GGT and ALP values were determinate using commercial kits. There was a statistically significant correlation between ALP and GGT. The same correlation was observed from TP, IgG and GGT. A positive γ globulin correlation was found between GGT, IgG and TP. ALP activity cannot be used as an indicator of immune passive transfer.
14

Detección de Cryptosporidium spp. en el pingüino de magallanes (Spheniscus magellanicus) en dos pingüineras de la región de Magallanes y Antártica chilena

Arredondo Elias de Quiros, Cristóbal Emilio January 2014 (has links)
Memoria para optar al título Profesional de Médico Veterinario / Cryptosporidium spp. es un agente parasitario protozoario zoonótico capaz de infectar a múltiples especies animales en todo el mundo, definido como prioritario para monitoreo en fauna silvestre. Produce diarrea en individuos inmunocomprometidos, siendo transmitido por vía fecal-oral, donde el agua juega un rol epidemiológico importante. Este patógeno, ya ha sido detectado en aguas marinas y superficiales y en animales acuáticos, incluyendo pingüinos de la Antártica. Los Sphenisciformes se consideran centinelas oceánicos, ya que reflejan cambios en la productividad oceánica y cambios ambientales producidos por actividades humanas. Con el objetivo de detectar este patógeno en pingüinos de zonas templadas, en este estudio se tomaron muestras a partir de tórulas cloacales y heces frescas desde el ambiente provenientes de Pingüinos de Magallanes (Spheniscus magellanicus) pertenecientes a dos colonias reproductivas, Isla Magdalena y Seno Otway, en la Región de Magallanes y Antártica Chilena. En Isla Magdalena, un 3,5% de las muestras obtenidas directamente desde las aves fueron positivas al agente, mientras que en Seno Otway un 3,4% de ellas dieron positivas, no existiendo diferencias significativas en los niveles de infección entre las colonias. Por otro lado, en las muestras ambientales, tomadas solamente en Isla Magdalena, se encontró un 29,1% de positividad a la presencia este parásito, siendo esta la primera descripción de Cryptosporidium spp. en S. magellanicus, y a su vez en pingüinos de zonas templadas. / Proyecto FONDECYT 1110255
15

A.C. electrokinetic bioassays : development of electrorotation assay for analytes in water

Goater, Andrew David January 1999 (has links)
The work described is primarily concerned with the understanding of the induced AC electrokinetic properties of the transmissive stages of two genera of waterborne protozoan pathogens, namely Cryptosporidium and Giardia. The assessment of viability through the use of electrorotation (ROT) has been investigated in comparison with conventional techniques. The optimum conditions for detennining C. parvum viability using ROT are described and discussed. Two Giardia and three Cryptosporidium species were investigated, as were a total of ten Cryptosporidium parvum isolates. With all species investigated a good correlation was found between the ROT response of clean particles and conventional vital dye techniques. Adherent bacteria on the particles surface have been identified as a major problem for subsequent ROT analysis. This is the first description of the effect of adherent bacteria on the dielectric response of biological particles . . A novel single layer electrode array was designed and successfully tested to overcome the problems of low particle concentration, interfering debris and particle position in the electrorotational electrodes. The device was shown to selectively concentrate particles into a central region whereupon their physiological state was then assessed through their ROT response. Modification of the device enabled the isolation of one or more particles onto a membrane, providing a suitable collection method for low particle number handling. The clearest demonstration to date of the effect of membrane integrity on the ROT response is described from spectra obtained for an oocyst before and after excystation in vitro. Storage time effects for oocysts of C. baileyi are also described as are isolate differences for C. parvum oocysts which are apparent in the low frequency region of the spectra. The implications of these results to the water industry and potential diagnostic applications of electrorotation are discussed.
16

Cryptosporidium: Isolate variation and humoral responses to sporozoite antigens.

Mead, Jan Renee. January 1988 (has links)
The humoral response of humans, calves and horses to Cryptosporidium sporozoite antigens was evaluated using a western blot technique. Sera from calves, humans and horses were obtained at various times following the detection of infection. Sera were reacted with detergent-solubilized, sporozoite antigens form sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The number of antigens recognized by immune sera from humans and animals increased with time post infection (P.I.). A 20 kDa antigen appeared to be a major sporozoite surface determinant since it was labelled via membrane protein biotinylation and recognized by mouse monoclonal antibodies using indirect immunofluorescence and western blotting. Detectable recognition of the 20 kDa band occurred in 3 week post infection (P.I.) sera from all species tested. Sera reactivity to the 20 kDa band diminished significantly within 5 months P.I. when infected humans had no further recurrence of cryptosporidial diarrhea. In contrast, 12 month P.I. sera from an individual constantly exposed to oocysts under working conditions was as strongly reactive as the 3 week convalescent sera. Therefore, reactivity to the 20 kDa antigen appeared to be a good indicator of exposure to Cryptosporidium. Anti-sporozoite indirect immunofluorescent titers decrease in reactivity from convalescent to post convalescent sera which correlated with western blot results. Chromosomal DNA of five Cryptosporidium parvum isolates and one Cryptosporidium baileyi isolate were compared by field inversion gel electrophoresis (FIGE). FIGE analyses of parasite DNA prepared from purified sporozoites versus intact oocysts showed no observable differences. Chromosomal DNA migration patterns of the five Cryptosporidium parvum isolates were indistinguishable. Distinct differences in chromosomal DNA were evident between the Cryptosporidium baileyi and Cryptosporidium parvum isolates, yet the overall pattern was similar. Five C. parvum isolates were also compared using two dimensional electrophoretic analyses. Silver stained patterns of sporozoite proteins showed a shift in a 106 kDa protein in three of the isolates. One isolate (Mexico) showed a complete absence of this protein (106 kDa) and the presence of an additional 40 kDa protein not found in any other isolate.
17

Interactions between Cryptosporidium parvum and the Intestinal Ecosystem

Douvropoulou, Olga 04 1900 (has links)
Cryptosporidium parvum is an apicomplexan protozoan parasite commonly causing diarrhea, particularly in infants in developing countries. The research challenges faced in the development of therapies against Cryptosporidium slow down the process of drug discovery. However, advancement of knowledge towards the interactions of the intestinal ecosystem and the parasite could provide alternative approaches to tackle the disease. Under this perspective, the primary focus of this work was to study interactions between Cryptosporidium parvum and the intestinal ecosystem in a mouse model. Mice were treated with antibiotics with different activity spectra and the resulted perturbation of the native gut microbiota was identified by microbiome studies. In particular, 16S amplicon sequencing and Whole Genome Sequencing (WGS) were used to determine the bacterial composition and the genetic repertoire of the fecal microbial communities in the mouse gut. Following alteration of the microbial communities of mice by application of antibiotic treatment, Cryptosporidium parasites were propagated in mice with perturbed microbiota and the severity of the infection was quantified. This approach enabled the prediction of the functional capacity of the microbial communities in the mouse gut and led to the identification of bacterial taxa that positively or negatively correlate in abundance with Cryptosporidium proliferation.
18

Avaliação da PCR em tempo real para detecção de Cryptosporidium parvum em amostras fecais de bezerros: Camila Guariz Homem. -

Homem, Camila Guariz [UNESP] 08 June 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:27:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-06-08Bitstream added on 2014-06-13T20:55:59Z : No. of bitstreams: 1 homem_cg_me_araca.pdf: 468363 bytes, checksum: b293bfbeab84c1a641ead5f90bd65ab2 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A infecção por Cryptosporidium parvum em bovinos se manifesta como enfermidade subclínica ou com presença de morbidade e mortalidade, particularmente quando há associação com outros agentes infecciosos. Cryptosporidium parvum apresenta ainda grande importância em saúde pública. Este trabalho teve como objetivo o desenvolvimento da reação em cadeia da polimerase em tempo real (qPCR) para detecção de C. parvum em amostras fecais de bezerros e sua comparação com a reação em cadeia da polimerase (nested PCR), rotineiramente utilizada para diagnóstico de Cryptosporidium spp.. Duzentas e nove amostras fecais de bezerros entre um dia e seis meses de idade foram examinadas pela qPCR para amplificação de fragmentos do gene da actina e pela nested PCR para o gene da subunidade 18S do rRNA. A qPCR apresentou positividade para C. parvum em 73,21% (153/209) das amostras, enquanto a nested PCR apresentou amplificação positiva para Cryptosporidium spp. em 56,5% (118/209) das amostras. A sensibilidade analítica da qPCR foi de aproximadamente um oocisto de C. parvum. Não se observou amplificação inespecífica de DNA Cryptosporidium bovis, Cryptosporidium andersoni, Cryptosporidium ryanae, Cryptosporidium canis, Cryptosporidium serpentis, Cryptosporidium galli, Cryptosporidium baileyi e Cryptosporidium genótipo II de aves. Desta forma, conclui-se que a qPCR para o gene da actina é uma técnica sensível e específica para detecção de C. parvum em amostras fecais de bezerros / The infection with Cryptosporidium parvum in cattle results in subclinical disease or in the presence of morbidity and mortality, particularly when associated with other infectious agents. This species is also an important public health problem. The aim of this research was to develop a real time polymerase chain reaction (qPCR) for detection of C. parvum DNA in fecal samples of calves, in comparison to a nested PCR routinely used for Cryptosporidium spp. diagnosis. Two hundred and nine fecal samples from calves aged between one day and six weeks were screened by qPCR specific for the actin gene of C. parvum and using nested PCR targeting the 18S rRNA gene of Cryptosporidium spp.. The qPCR showed positivity for C. parvum in 73,21% (153/209) of the samples, and nested PCR was positive for Cryptosporidium spp. in 56.5% (118/209) of the samples. The analytical sensitivity of qPCR foi de aproximadamente one oocyst C. parvum per reaction tube. Evaluation of analytical specificity did not reveal inespecific amplification for DNA of the following Cryptosporidium species and genotypes: C. bovis, C. andersoni, C. ryanae, C. canis, C. serpentis, C. galli, C. baileyi and avian genotype II. These results allowed the conclusion that qPCR for actin gene is a sensitive and specific technique for detection of C. parvum in fecal samples from calves
19

Avaliação da PCR em tempo real para detecção de Cryptosporidium parvum em amostras fecais de bezerros / Camila Guariz Homem. -

Homem, Camila Guariz. January 2011 (has links)
Orientador: Marcelo Vasconcelos Meireles / Banca: Fernando de Almeida Borges / Banca: Caris Maroni Nunes / Resumo: A infecção por Cryptosporidium parvum em bovinos se manifesta como enfermidade subclínica ou com presença de morbidade e mortalidade, particularmente quando há associação com outros agentes infecciosos. Cryptosporidium parvum apresenta ainda grande importância em saúde pública. Este trabalho teve como objetivo o desenvolvimento da reação em cadeia da polimerase em tempo real (qPCR) para detecção de C. parvum em amostras fecais de bezerros e sua comparação com a reação em cadeia da polimerase (nested PCR), rotineiramente utilizada para diagnóstico de Cryptosporidium spp.. Duzentas e nove amostras fecais de bezerros entre um dia e seis meses de idade foram examinadas pela qPCR para amplificação de fragmentos do gene da actina e pela nested PCR para o gene da subunidade 18S do rRNA. A qPCR apresentou positividade para C. parvum em 73,21% (153/209) das amostras, enquanto a nested PCR apresentou amplificação positiva para Cryptosporidium spp. em 56,5% (118/209) das amostras. A sensibilidade analítica da qPCR foi de aproximadamente um oocisto de C. parvum. Não se observou amplificação inespecífica de DNA Cryptosporidium bovis, Cryptosporidium andersoni, Cryptosporidium ryanae, Cryptosporidium canis, Cryptosporidium serpentis, Cryptosporidium galli, Cryptosporidium baileyi e Cryptosporidium genótipo II de aves. Desta forma, conclui-se que a qPCR para o gene da actina é uma técnica sensível e específica para detecção de C. parvum em amostras fecais de bezerros / Abstract: The infection with Cryptosporidium parvum in cattle results in subclinical disease or in the presence of morbidity and mortality, particularly when associated with other infectious agents. This species is also an important public health problem. The aim of this research was to develop a real time polymerase chain reaction (qPCR) for detection of C. parvum DNA in fecal samples of calves, in comparison to a nested PCR routinely used for Cryptosporidium spp. diagnosis. Two hundred and nine fecal samples from calves aged between one day and six weeks were screened by qPCR specific for the actin gene of C. parvum and using nested PCR targeting the 18S rRNA gene of Cryptosporidium spp.. The qPCR showed positivity for C. parvum in 73,21% (153/209) of the samples, and nested PCR was positive for Cryptosporidium spp. in 56.5% (118/209) of the samples. The analytical sensitivity of qPCR foi de aproximadamente one oocyst C. parvum per reaction tube. Evaluation of analytical specificity did not reveal inespecific amplification for DNA of the following Cryptosporidium species and genotypes: C. bovis, C. andersoni, C. ryanae, C. canis, C. serpentis, C. galli, C. baileyi and avian genotype II. These results allowed the conclusion that qPCR for actin gene is a sensitive and specific technique for detection of C. parvum in fecal samples from calves / Mestre
20

Remoção de (oo)cistos de protozoários e de estrogenicidade em sistemas combinados de tratamento de esgoto sanitário / Removal microorganisms, (oo)cysts of protozoa and estrogenicity in combined wastewater treatment systems

Marcos Schaaf Teixeira da Silva 08 August 2014 (has links)
Atualmente há um grande interesse em estudos voltados para sistema de tratamento de esgoto sanitário. Isso se deve principalmente pela presença de microrganismos e substâncias que podem interferir na saúde humana e ambiental. Dentre os microrganismos patogênicos responsáveis por transmissão de doenças estão os protozoários Giardia spp. e Cryptosporidium spp. No que se refere às substâncias nocivas à saúde humana e ambiental podem ser citados os desreguladores endócrinos que agem sobre o sistema endócrino de homens e animais causando efeitos adversos. Baseado na importância destes estudos, o presente trabalho teve por objetivo avaliar a eficiência de remoção de protozoários patogênicos - Giardia spp. e Cryptosporidium spp. e da atividade de estrogenicidade em processos de tratamento de esgoto sanitário constituídos por reator UASB, sistema de lodos ativados e filtro de areia. Também foram avaliados os padrões de qualidade dos efluentes do reator UASB e sistema de lodos ativados utilizando sulfato de alumínio e cloreto férrico. A combinação dos processos biológicos sequenciais apresentou robustez em termos de remoção de matéria orgânica, microrganismos indicadores e (oo)cistos. A desinfecção com cloro mostrou-se eficiente em inativar os microrganismos indicadores: coliformes totais e Escherichia coli. A atividade estrogênica, avaliada pelo teste YES, foi maior no efluente do lodo ativado e do filtro de areia devido à conjugação dos compostos estrogênicos no esgoto bruto. Detectou-se toxicidade à levedura utilizada no teste YES (Saccharomyces cerevisae), principalmente nas menores diluições, a qual interferiu na expressão da estrogenicidade impossibilitando o cálculo em termos de concentração equivalente de 17β-estradiol. / Currently there is great interest in studies related to the wastewater treatment system. This is mainly for the present of microorganisms and substances that can interfere with human and environmental health. Among the pathogens responsible for diDEse transmission are protozoa Giardia spp. and Cryptosporidium spp. With regard to substances harmful to human and environmental health can cite endocrine disrupters that act on the endocrine system of humans and animals causing adverse effects. Based on the importance of these studies, the present study aimed to evaluate the efficiency of removal of pathogenic protozoa - Giardia spp. and Cryptosporidium spp. - Activity and estrogenicity in processes of wastewater treatment consisting of UASB reactor, activated sludge system and sand filter. We also evaluated the quality standards of the effluent of the UASB reactor and activated sludge system using aluminum sulfate and ferric chloride. The combination of hardiness sequential biological processes presented in terms of removal of organic matter, microorganisms and indicators (oo) cysts. The chlorine disinfection proved effective in inactivating microorganisms indicators: total coliforms e Escherichia coli. The estrogenic activity, assessed by the YES assay, was higher in the effluent of the activated sludge and sand filter due to a combination of estrogenic compounds in raw sewage. Was detected toxicity to the yeast used in the YES assay (Saccharomyces cerevisiae), mainly in the lower dilutions, which interfered with the expression of estrogenicity it impossible to calculate in terms of an equivalent concentration of 17β-estradiol.

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