The molecular basis for the gene-for-gene relationship of Vm-resistance in apple to Venturia inaequalis was investigated. Incompatible reactions involved a hypersensitive response (HR), which was accompanied by the accumulation of dark brown pigments and autofluorescent materials in epidermal and mesophyll cells at the site of invasion. Cell-free culture filtrates of the avirulent isolate elicited an HR in the Vm host (h5) leaves, but not in the susceptible host (h1). The elicitor activity was resistant to boiling but was abolished by proteinase K digestion. Elicitation of HR was used to monitor purification of the avirulence factor, AVRVm, from liquid cultures of the avirulent isolate following ultrafiltration, acetone precipitation and ion-exchange chromatography. The purest fraction contained three major proteins all with low isoelectric points (pI 3.0-4.5). The fraction also elicited HR on the differential host h4, but not on other resistant hosts (h2, h3 and h6) tested. Three candidate AVRVm proteins were identified and amino acid sequences were obtained using Edman degradation and mass spectrometry. Nucleotide sequences corresponding to these proteins were found in databases of V. inaequalis expressed sequence tags. There were no polymorphisms evident between avirulent and virulent isolates (representing races 1 and 5 respectively) either at genomic DNA or cDNA level of the full open reading frames. RT-PCR revealed that all genes were expressed in both avirulent and virulent isolates during in vitro and in planta growth. All three genes showed similar levels of expression between avirulent and virulent isolates during their in vitro growth. However, preliminary RT-PCR experiments showed that two of these genes were likely to be expressed at lower levels in the virulent compared with the avirulent isolate during compatible infection. Implications of this difference in expression and the future experiments to identify the genuine AvrVm gene were discussed.

The molecular basis for the gene-for-gene relationship of Vm-resistance in apple to Venturia inaequalis was investigated. Incompatible reactions involved a hypersensitive response (HR), which was accompanied by the accumulation of dark brown pigments and autofluorescent materials in epidermal and mesophyll cells at the site of invasion. Cell-free culture filtrates of the avirulent isolate elicited an HR in the Vm host (h5) leaves, but not in the susceptible host (h1). The elicitor activity was resistant to boiling but was abolished by proteinase K digestion. Elicitation of HR was used to monitor purification of the avirulence factor, AVRVm, from liquid cultures of the avirulent isolate following ultrafiltration, acetone precipitation and ion-exchange chromatography. The purest fraction contained three major proteins all with low isoelectric points (pI 3.0-4.5). The fraction also elicited HR on the differential host h4, but not on other resistant hosts (h2, h3 and h6) tested. Three candidate AVRVm proteins were identified and amino acid sequences were obtained using Edman degradation and mass spectrometry. Nucleotide sequences corresponding to these proteins were found in databases of V. inaequalis expressed sequence tags. There were no polymorphisms evident between avirulent and virulent isolates (representing races 1 and 5 respectively) either at genomic DNA or cDNA level of the full open reading frames. RT-PCR revealed that all genes were expressed in both avirulent and virulent isolates during in vitro and in planta growth. All three genes showed similar levels of expression between avirulent and virulent isolates during their in vitro growth. However, preliminary RT-PCR experiments showed that two of these genes were likely to be expressed at lower levels in the virulent compared with the avirulent isolate during compatible infection. Implications of this difference in expression and the future experiments to identify the genuine AvrVm gene were discussed.

The molecular basis for the gene-for-gene relationship of Vm-resistance in apple to Venturia inaequalis was investigated. Incompatible reactions involved a hypersensitive response (HR), which was accompanied by the accumulation of dark brown pigments and autofluorescent materials in epidermal and mesophyll cells at the site of invasion. Cell-free culture filtrates of the avirulent isolate elicited an HR in the Vm host (h5) leaves, but not in the susceptible host (h1). The elicitor activity was resistant to boiling but was abolished by proteinase K digestion. Elicitation of HR was used to monitor purification of the avirulence factor, AVRVm, from liquid cultures of the avirulent isolate following ultrafiltration, acetone precipitation and ion-exchange chromatography. The purest fraction contained three major proteins all with low isoelectric points (pI 3.0-4.5). The fraction also elicited HR on the differential host h4, but not on other resistant hosts (h2, h3 and h6) tested. Three candidate AVRVm proteins were identified and amino acid sequences were obtained using Edman degradation and mass spectrometry. Nucleotide sequences corresponding to these proteins were found in databases of V. inaequalis expressed sequence tags. There were no polymorphisms evident between avirulent and virulent isolates (representing races 1 and 5 respectively) either at genomic DNA or cDNA level of the full open reading frames. RT-PCR revealed that all genes were expressed in both avirulent and virulent isolates during in vitro and in planta growth. All three genes showed similar levels of expression between avirulent and virulent isolates during their in vitro growth. However, preliminary RT-PCR experiments showed that two of these genes were likely to be expressed at lower levels in the virulent compared with the avirulent isolate during compatible infection. Implications of this difference in expression and the future experiments to identify the genuine AvrVm gene were discussed.

O cão (Canis familiaris) é o principal reservatório de Leishmania (Leishmania) infantum. Sua alta competência em transmitir o parasito para o inseto vetor contribui para a manutenção do ciclo e aumento do risco para os humanos em áreas endêmicas. O amplo espectro de manifestações clínicas da leishmaniose visceral canina (LVC) torna seu diagnóstico bastante complexo, já que essas manifestações podem se sobrepor àquelas causadas por outros agentes infecciosos. Fator agravante é que a infecção, na maior parte das vezes, tem caráter subclínico, podendo passar despercebida. Diante disto, um diagnóstico confiável se faz necessário para confirmar uma suspeita clínica ou infecção inaparente. A reação em cadeia da polimerase (PCR) tem contribuído em muito para o aumento da sensibilidade do diagnóstico, e seu uso mostra que a prevalência da infecção canina por L. (L.) infantum em áreas endêmicas pode ser bem maior do que a apontada pela sorologia. É sabido que um dos fatores limitantes do emprego de uma técnica diagnóstica em larga escala refere-se à coleta do material clínico que, idealmente, deve ser simples, rápida e indolor. Assim, entende-se que a associação da PCR com amostras não invasivas, de fácil coleta, poderia representar uma contribuição importante para o diagnóstico da LVC. Dessa forma, a proposta do presente projeto foi investigar o valor do swab oral (SO) na detecção de L. (L.) infantum em cães oriundos de áreas onde ocorre transmissão do parasito, através do uso da PCR em tempo real, considerada a mais sensível dentre as técnicas moleculares. Para tanto, comparamos sua positividade com a encontrada em outra amostra não invasiva (swab conjuntival= SC), pouco invasiva (sangue periférico= SG) e invasiva (aspirado de linfonodo=LN) e com a sorologia, considerando grupos clínicos, carga parasitária, índice de concordância entre os resultados, e a combinação dos resultados das diferentes amostras e a sorologia com aqueles obtidos no SO. Noventa e dois cães com comprovada infecção participaram do estudo. Os animais foram classificados em sintomáticos (n=63) e assintomáticos (n=29), de acordo com o exame físico e provas laboratoriais. No presente estudo a positividade do SO (67,4%) foi equivalente a do SC (68,5 %), maior do que a encontrada no SG (52,2%), e menor quando comparada ao LN (84,8%). Considerando os grupos clínicos, o SO foi positivo em 81 % dos cães sintomáticos e em 37,9 % dos assintomáticos. A positividade encontrada no SC também foi maior no grupo sintomático em relação ao assintomático (82,5 % x 37,9 %), assim como no LN (93,7 % x 65,5 %), mas não no SG (62,1 % x 47,6 %) e na sorologia (77,8 % x 79,3 %). Salienta-se que o SO foi positivo em 35 % dos cães com sorologia negativa (n=20), o SC em 35%, o SG em 40 %, o LN em 70 %, e OS+CS em 60% deles. A concordância dos resultados do SO foi moderada em relação à conjuntiva (k= 0,3) e fraca em relação às demais amostras e a sorologia (0.2 < k < 0.3). A carga parasitária do SO, por sua vez, não se diferiu da conjuntival, ambas foram maiores do que a encontrada no SG, e o LN apresentou a maior carga, mostrando uma clara correlação da intensidade do parasitismo com os índices de positividade obtidos. O LN mostrou o maior parasitismo entre as amostras analisadas. A combinação dos resultados do SO e SC atingiram 84 % de positividade nos 92 cães estudados, 92,1 % no grupo sintomático e 65,5 % no assintomático. Em suma, o presente estudo mostrou a presença do DNA de L. (L.) infantum no swab oral de cães infectados através da PCR em tempo real, revelando seu potencial uso no diagnóstico da LVC em cães com suspeita clínica dada a sua alta positividade nos animais com sintomatologia, equivalente à encontrada na amostra invasiva, o aspirado de linfonodo. Em oposição, encontrou-se baixa positividade nos cães assintomáticos, mas seu uso combinado com outra amostra não invasiva, a conjuntiva, atingiu patamares satisfatórios. O fato do SO ter sido positivo em parte dos animais soronegativos aponta vantagem adicional do seu uso na investigação de infecção por L. (L.) infantum em inquéritos epidemiológicos ou mesmo na rotina clínica. Por fim, os nossos resultados mostraram que a combinação de testes e amostras é necessária para a identificação de cães infectados por L. (L.) infantum, e que a PCR com o swab oral, especialmente associado ao swab conjuntival, pode contribuir de forma significativa para o diagnóstico da infecção canina, seja ela sintomática ou assintomática / Dog (Canis familiaris) is the major reservoir of Leishmania (L.) infantum. Its high competence for transmitting the parasite to the vector contributes to the maintenance of the cycle and for increasing risk to humans in endemic areas. The wide spectrum of clinical manifestations of canine visceral leishmaniasis (CVL) makes the diagnosis quite complex, since the symptoms can overlap those caused by other infectious agents. Of note, the infection is mostly subclinical, making the diagnosis even more difficult. Therefore, an accurate diagnosis is necessary to confirm a clinical suspicion or the silent infection. The polymerase chain reaction (PCR) has greatly contributed for increasing the diagnostic sensitivity, and its use shows that L. (L.) infantum canine infection in endemic areas may be much higher than that pointed by serology. It is known that one limiting factor of using a diagnostic method in large scale refers to the collection of clinical samples which should be ideally simple, quick, and painless. Thus, it is understood that the association of PCR with non-invasive samples could represent an important contribution to the diagnosis of CVL. Therefore, the purpose of this study was to investigate the value of the oral swab (OS) in detecting L. (L.) infantum in dogs from areas of parasite transmission through the use of real-time PCR that is considered the most sensitive among the molecular techniques. To this end, we compared the OS positivity with that found in other non-invasive (conjunctival swab = CS), minimally invasive (blood = BL) and invasive (lymph node aspirate = LN) samples and serology, considering clinical groups, parasite load, agreement among results, and the combination of results from different samples and serology with those obtained with OS. Ninety-two dogs with proven infection were selected for this present study. The animals were divided into symptomatic (n = 63) and asymptomatic (n = 29) dogs, according to the physical examination and laboratory tests. Here, the positivity in OS (67.4%) was equivalent to the CS (68.5%), higher than that found in BL (52.2%), and lower when compared to LN (84.8%). Regarding clinical groups, OS was positive in 81% of the symptomatic dogs and in 37.9% of asymptomatic ones. The positivity in CS was also higher in the symptomatic compared to the asymptomatic group (82.5% x 37.9%) and in LN (93.7% x 65.5%), but not in BL (62.1% x 47.6%) and serology (77.8% x 79.3%). Noteworthy, the OS was positive in 35% of dogs with negative serology (n = 20), CS in 35%, BL in 40% and LN in 70%. Moderate agreement was found between OS results and CS results (k = 0.3) and weak in comparison to other samples and serology (0.2 < k < 0.3). The parasite load was equivalent between OS and CS, both were higher than that found in BL, and LN presented the highest burden, showing that parasitism intensity and the positivity rates are correlated. The combination of OS and CS results reached 84% positivity in 92 dogs studied, 92.1% for symptomatic dogs and 65.5% for asymptomatic ones. In summary, the present study showed the presence of L. (L.) infantum DNA in oral swab of infected dogs by real-time PCR, revealing its potential use for diagnosing CVL in animals with clinical suspicion due to its high positivity in dogs with symptoms, equivalent to that found in invasive sample, the lymph node aspirate. In contrast, low positivity was found in asymptomatic dogs, but the combined use with other non-invasive sample, the conjunctiva, reached satisfactory levels. OS positivity found in part of the seronegative animals points additional advantage of using OS in the investigation of L. (L.) infantum infection in epidemiological surveys or in clinical practice. Finally, our findings pointed that combination of tests and samples is required for identifying dogs infected with L. (L.) infantum, and that the PCR with oral swab, especially associated with the conjunctival swab, can contribute for diagnosing both asymptomatic and symptomatic dogs

Submitted by Priscila Nascimento (pnascimento@icict.fiocruz.br) on 2012-11-13T18:17:33Z No. of bitstreams: 1 carlos-renato-calvet.pdf: 572867 bytes, checksum: 445d1b96d9a8d9baadaf7ef3d8852421 (MD5) / Made available in DSpace on 2012-11-13T18:17:33Z (GMT). No. of bitstreams: 1 carlos-renato-calvet.pdf: 572867 bytes, checksum: 445d1b96d9a8d9baadaf7ef3d8852421 (MD5) Previous issue date: 2007 / Fundação Oswaldo Cruz. Instituto de Tecnologia em Imunobiológicos. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil. / No Brasil, a Leishmaniose Visceral (LV) é uma antropozoonose que representa grave problema de saúde pública, presente em 19 estados da federação, com cerca de 3.500 casos humanos anuais. O agente etiológico da LV é um protozoário do gênero Leishmania, cujos vetores são insetos da sub-família Phlebotominae, sendo o Lutzomyia longipalpisa principal espécie das Américas. O cão é o mais importante reservatório da doença, atuando como hospedeiro doméstico o que torna necessária maior atenção sobre o papel destes animais na transmissão da doença e conseqüente urbanização. O controle da população canina consiste, principalmente, na eliminação de cães infectados e diagnosticados por exames parasitológicos ou sorológicos positivos para a leishmaniose visceral canina (LVC). Resultados sorológicos falso-positivos e falso-negativos podem levar à eutanásia animais supostamente infectados, determinando dados epidemiológicos imprecisos. Bio-Manguinhos produz e distribui os kits de LVC mais utilizados na rede de Laboratório Público do país: incluem-se os testes imunoenzimático (ELISA) e o teste de Imunofluorescência Indireta (IFI). O objetivo desta Dissertação foi pôr em execução um Programa de Avaliação Externa da Qualidade dos testes sorológicos da LVC em instituições localizadas em áreas endêmicas do país. Distribuímos, em outubro de 2006, carta-convite e questionário de cadastramento a 51 instituições responsáveis por realizar o diagnóstico sorológico no país com 78% de adesão (40). Sendo assim, em dezembro de 2006, enviamos um painel sorológico composto por 6 amostras de soro canino, por quatro (4) amostras positivas e duas (2) amostras negativas, todas com certeza diagnóstica confirmadapor ELISA e IFI, junto a um protocolo para o preenchimento dos resultados obtidos. Dos 75% laboratórios (30) que realizaram os exames, 30% (9) foram não-conformes, totalizando 10 erros. Os percentuais de resultados incorretos por metodologia obtidos nesse painel de AEQ-LVC foram 3,7% (4/108 / ELISA) e 3,4% (6/176 / IFI). As respostas dos questionários e dos resultados na sorologia dos painéis foram armazenadas em um banco de dados construído em software estatístico SPSS WIN 11.0. Apoiado nas informações do banco de dados, diversos aspectos foram analisadas (percentil, mediana, desvio-padrão). Além disso, correlações entre realização prévia em Programa de Avaliação Externa da Qualidade (AEQ) foram correlacionadas àsvariáveis de estrutura e processo. A maioria dos laboratórios pertence à Rede Pública, sendo estaduais pouco mais da metade (55%). Apresentam funcionáriosexclusivos para realização da sorologia para LVC em 70% das instituições, com metade dos serviços contando, pelo menos, com um funcionário com instrução superior. Independente do nível de instrução, a experiência dos funcionários na execução do exame de IFI aproxima-se do dobro (em média 6 anos) daquela relativa à execução do ELISA. Quanto às informações estruturais, itens ligados à qualidade demonstraram que 77,5% das instituições possuem Procedimentos Operacionais Padrão (POP); 95,0% afirmaram utilizar equipamento de proteção individual (EPI) emais da metade (60%) dos laboratórios não calibra equipamentos e dentre esses um terço (31,3%) o faz com periodicidade irregular ou acima da anual. Por intermédio de painéis sorológicos, o AEQ-LVC pretende contribuir como importante instrumento para melhoria do desempenho dos laboratórios públicos. / Visceral leishmaniasis (VL) is one anthropozoonose that represents a serious problem of public health in Brazil with 3.500 new annual cases in 19 states of the country. The etiological agent of VL is a protozoa of the genus Leishmania, whose vectors are insects of the sub-family Phlebotominae, being the Lutzomyia longipalpis, the main species found in the Americas. The dog is the most important reservoir of the parasite acting as a domestic host, demanding agreater attention on the role of these animals in the transmission of the illness and its consequent urbanization. The control of the canine population consists mainly inthe elimination of infected dogs, diagnosed by parasitological examinations or positive serological tests for canine visceral leishmaniasis (CVL). False-positive and false-negative serological results may lead to the euthanasia of supposedly infected animals and the attainment of imprecise epidemiological data. Bio-Manguinhos produces and distributes the most consumed kits for CVL used in Brazil’s public laboratory network including immunoenzyme (ELISA) and indirect immunofluorescence (IFI) tests. The objective of the present study was to initiate a Program of External Quality Assessment (EQA) for CVL serological tests, in institutions located in endemic areas of the country. In October 2006, an invitation letter together with anenrollment form was sent to 51 institutions responsible for the serological diagnosis in the country to which 78% (40) had adhered. In December 2006, along with a protocol to be fulfilled with the results a serological panel was sent containing: four (4) positive and two (2) negative samples of canine serum, all of them confirmed by ELISA and IFI. Of the 30 (75%) laboratories that performed the exams, 9 (30%) werenot in agreement, totalizing 10 errors. The percentage of incorrect results by methodology obtained for this EQA-CVL panel was 3,7% (4/108) for ELISA and 3,4% (6/176) for IFI. The information obtained from the serological panel results was stored in a data bank, constructed in SPSS WIN 11.0 statistical software. Based on this data bank, some statistical were analyzed. Furthermore, correlations between previous programs of external quality assessment (EQA) were performed to compare structural and process variables. The majority of the laboratories belong to the public network with more than a half (55%) belonging to the state. Exclusive employees that perform CVL serology were found in 70% of the institutions and half of the servicespossess at least one employee with superior instruction. Independently of the instruction level, the employees experience on IFI is about 2 times greater (6 years) than thatrelated to ELISA tests. Concerning structural information, quality related items showed that 77,5% of the institutions possess Standard Operating Procedures (SOP), 95,0% use Individual Protection Equipment (IPE), more than a half (60%) do not calibrate equipments and amongst the ones that do the calibration, one-third (31,3%)make it with irregularly or over annual periodicity. Through serological panels, theEQA-CVL might contribute as an important instrument to improve the performance of public laboratories.

O cão (Canis familiaris) é o principal reservatório de Leishmania (Leishmania) infantum. Sua alta competência em transmitir o parasito para o inseto vetor contribui para a manutenção do ciclo e aumento do risco para os humanos em áreas endêmicas. O amplo espectro de manifestações clínicas da leishmaniose visceral canina (LVC) torna seu diagnóstico bastante complexo, já que essas manifestações podem se sobrepor àquelas causadas por outros agentes infecciosos. Fator agravante é que a infecção, na maior parte das vezes, tem caráter subclínico, podendo passar despercebida. Diante disto, um diagnóstico confiável se faz necessário para confirmar uma suspeita clínica ou infecção inaparente. A reação em cadeia da polimerase (PCR) tem contribuído em muito para o aumento da sensibilidade do diagnóstico, e seu uso mostra que a prevalência da infecção canina por L. (L.) infantum em áreas endêmicas pode ser bem maior do que a apontada pela sorologia. É sabido que um dos fatores limitantes do emprego de uma técnica diagnóstica em larga escala refere-se à coleta do material clínico que, idealmente, deve ser simples, rápida e indolor. Assim, entende-se que a associação da PCR com amostras não invasivas, de fácil coleta, poderia representar uma contribuição importante para o diagnóstico da LVC. Dessa forma, a proposta do presente projeto foi investigar o valor do swab oral (SO) na detecção de L. (L.) infantum em cães oriundos de áreas onde ocorre transmissão do parasito, através do uso da PCR em tempo real, considerada a mais sensível dentre as técnicas moleculares. Para tanto, comparamos sua positividade com a encontrada em outra amostra não invasiva (swab conjuntival= SC), pouco invasiva (sangue periférico= SG) e invasiva (aspirado de linfonodo=LN) e com a sorologia, considerando grupos clínicos, carga parasitária, índice de concordância entre os resultados, e a combinação dos resultados das diferentes amostras e a sorologia com aqueles obtidos no SO. Noventa e dois cães com comprovada infecção participaram do estudo. Os animais foram classificados em sintomáticos (n=63) e assintomáticos (n=29), de acordo com o exame físico e provas laboratoriais. No presente estudo a positividade do SO (67,4%) foi equivalente a do SC (68,5 %), maior do que a encontrada no SG (52,2%), e menor quando comparada ao LN (84,8%). Considerando os grupos clínicos, o SO foi positivo em 81 % dos cães sintomáticos e em 37,9 % dos assintomáticos. A positividade encontrada no SC também foi maior no grupo sintomático em relação ao assintomático (82,5 % x 37,9 %), assim como no LN (93,7 % x 65,5 %), mas não no SG (62,1 % x 47,6 %) e na sorologia (77,8 % x 79,3 %). Salienta-se que o SO foi positivo em 35 % dos cães com sorologia negativa (n=20), o SC em 35%, o SG em 40 %, o LN em 70 %, e OS+CS em 60% deles. A concordância dos resultados do SO foi moderada em relação à conjuntiva (k= 0,3) e fraca em relação às demais amostras e a sorologia (0.2 < k < 0.3). A carga parasitária do SO, por sua vez, não se diferiu da conjuntival, ambas foram maiores do que a encontrada no SG, e o LN apresentou a maior carga, mostrando uma clara correlação da intensidade do parasitismo com os índices de positividade obtidos. O LN mostrou o maior parasitismo entre as amostras analisadas. A combinação dos resultados do SO e SC atingiram 84 % de positividade nos 92 cães estudados, 92,1 % no grupo sintomático e 65,5 % no assintomático. Em suma, o presente estudo mostrou a presença do DNA de L. (L.) infantum no swab oral de cães infectados através da PCR em tempo real, revelando seu potencial uso no diagnóstico da LVC em cães com suspeita clínica dada a sua alta positividade nos animais com sintomatologia, equivalente à encontrada na amostra invasiva, o aspirado de linfonodo. Em oposição, encontrou-se baixa positividade nos cães assintomáticos, mas seu uso combinado com outra amostra não invasiva, a conjuntiva, atingiu patamares satisfatórios. O fato do SO ter sido positivo em parte dos animais soronegativos aponta vantagem adicional do seu uso na investigação de infecção por L. (L.) infantum em inquéritos epidemiológicos ou mesmo na rotina clínica. Por fim, os nossos resultados mostraram que a combinação de testes e amostras é necessária para a identificação de cães infectados por L. (L.) infantum, e que a PCR com o swab oral, especialmente associado ao swab conjuntival, pode contribuir de forma significativa para o diagnóstico da infecção canina, seja ela sintomática ou assintomática / Dog (Canis familiaris) is the major reservoir of Leishmania (L.) infantum. Its high competence for transmitting the parasite to the vector contributes to the maintenance of the cycle and for increasing risk to humans in endemic areas. The wide spectrum of clinical manifestations of canine visceral leishmaniasis (CVL) makes the diagnosis quite complex, since the symptoms can overlap those caused by other infectious agents. Of note, the infection is mostly subclinical, making the diagnosis even more difficult. Therefore, an accurate diagnosis is necessary to confirm a clinical suspicion or the silent infection. The polymerase chain reaction (PCR) has greatly contributed for increasing the diagnostic sensitivity, and its use shows that L. (L.) infantum canine infection in endemic areas may be much higher than that pointed by serology. It is known that one limiting factor of using a diagnostic method in large scale refers to the collection of clinical samples which should be ideally simple, quick, and painless. Thus, it is understood that the association of PCR with non-invasive samples could represent an important contribution to the diagnosis of CVL. Therefore, the purpose of this study was to investigate the value of the oral swab (OS) in detecting L. (L.) infantum in dogs from areas of parasite transmission through the use of real-time PCR that is considered the most sensitive among the molecular techniques. To this end, we compared the OS positivity with that found in other non-invasive (conjunctival swab = CS), minimally invasive (blood = BL) and invasive (lymph node aspirate = LN) samples and serology, considering clinical groups, parasite load, agreement among results, and the combination of results from different samples and serology with those obtained with OS. Ninety-two dogs with proven infection were selected for this present study. The animals were divided into symptomatic (n = 63) and asymptomatic (n = 29) dogs, according to the physical examination and laboratory tests. Here, the positivity in OS (67.4%) was equivalent to the CS (68.5%), higher than that found in BL (52.2%), and lower when compared to LN (84.8%). Regarding clinical groups, OS was positive in 81% of the symptomatic dogs and in 37.9% of asymptomatic ones. The positivity in CS was also higher in the symptomatic compared to the asymptomatic group (82.5% x 37.9%) and in LN (93.7% x 65.5%), but not in BL (62.1% x 47.6%) and serology (77.8% x 79.3%). Noteworthy, the OS was positive in 35% of dogs with negative serology (n = 20), CS in 35%, BL in 40% and LN in 70%. Moderate agreement was found between OS results and CS results (k = 0.3) and weak in comparison to other samples and serology (0.2 < k < 0.3). The parasite load was equivalent between OS and CS, both were higher than that found in BL, and LN presented the highest burden, showing that parasitism intensity and the positivity rates are correlated. The combination of OS and CS results reached 84% positivity in 92 dogs studied, 92.1% for symptomatic dogs and 65.5% for asymptomatic ones. In summary, the present study showed the presence of L. (L.) infantum DNA in oral swab of infected dogs by real-time PCR, revealing its potential use for diagnosing CVL in animals with clinical suspicion due to its high positivity in dogs with symptoms, equivalent to that found in invasive sample, the lymph node aspirate. In contrast, low positivity was found in asymptomatic dogs, but the combined use with other non-invasive sample, the conjunctiva, reached satisfactory levels. OS positivity found in part of the seronegative animals points additional advantage of using OS in the investigation of L. (L.) infantum infection in epidemiological surveys or in clinical practice. Finally, our findings pointed that combination of tests and samples is required for identifying dogs infected with L. (L.) infantum, and that the PCR with oral swab, especially associated with the conjunctival swab, can contribute for diagnosing both asymptomatic and symptomatic dogs

Indiana University-Purdue University Indianapolis (IUPUI) / While breast cancer is the second most commonly diagnosed cancer worldwide, its causes and natural history are not well defined. The female mammary organ is unique in that it does not reach full maturity until the lactation cycle following pregnancy. This cycle entails extensive growth and reorganization of the primitive epithelial ductal network. Following lactation, these same epithelial cells undergo an equally extensive program of apoptosis and involution. The mammary gland's sensitivity to pro-growth and pro-apoptotic signals may partly explain its proclivity to develop cancers. For epithelial cells to become transformed they must lose intracellular organization known as polarity as differentiated epithelial tissues are refractory to aberrant growth. One essential component of epithelial to mesenchymal transition is the intrinsic capacity of cells to repurpose polarity constituents to promote growth. Recently, a novel mechanism of organ size control has been shown to repurpose the apical junctional associated protein Yap into the nucleus where it functions as a transcriptional coactivator promoting growth and dedifferentiation. The focus of my work has been on a family of adaptor proteins termed Amots that have been shown to scaffold Yap and inhibit growth signaling. Specifically, I have shown that the 80KDa form of Amot, termed Amot80, acts as a dominant negative to the other Amot proteins to promote cell growth while reducing cell differentiation. Amot80 was found to promote the prolonged activation of MAPK signaling. Further, Amot80 expression was also found to enhance the transcriptional activity of Yap. This effect likely underlies the ability of Amot80 to drive disorganized overgrowth of MCF10A cells grown in Matrigel̈™. Overall, these data suggest a mechanism whereby the balance of Amot proteins controls the equilibrium between growth and differentiation within mammary epithelial tissues.

Indiana University-Purdue University Indianapolis (IUPUI) / Signal transducer and activator of transcription 3 (STAT3) is constitutively activated in malignant tumors, and its activation is associated with high histological grade and advanced cancer stage. STAT3 has been shown to play important roles in multiple aspects of cancer aggressiveness including proliferation, survival, self-renewal, migration, invasion, angiogenesis and immune response by regulating the expression of diverse downstream target genes. Thus, inhibiting STAT3 promises to be an attractive strategy for treatment of advanced tumors with metastatic potential. We firstly identified a STAT3 inhibitor, inS3-54, by targeting the DNA-binding site of STAT3 using an in-silico screening approach; however, inS3-54 was finally found not to be appropriate for further studies because of low specificity on STAT3 and poor absorption in mice. To develop an effective and specific STAT3 inhibitor, we identified 89 analogues for the structure-activity relationship analysis. By using hematopoietic progenitor cells isolated from wild-type and STAT3 conditional knockout mice, further studies showed that three analogues (A18, A26 and A69) only inhibited STAT3-dependent colony formation of hematopoietic progenitor cells, indicating a higher selectivity for STAT3 than their parental compound, inS3-54. These compounds were found to (1) inhibit STAT3-specific DNA binding activity; (2) bind to STAT3 protein; (3) suppress proliferation of cancer cells harboring aberrant STAT3 signaling; (4) inhibit migration and invasion of cancer cells and (5) inhibit STAT3-dependent expression of downstream targets by blocking the binding of STAT3 to the promoter regions of responsive genes in cells. In addition, A18 can reduce tumor growth in a mouse xenograft model of lung cancer with little effect on body weight. Taken together, we conclude that it is feasible to inhibit STAT3 by targeting its DNA-binding domain for discovery of anticancer therapeutics.

Indiana University-Purdue University Indianapolis (IUPUI) / Mammary ductal epithelial cell growth is controlled by microenvironmental signals in serum under both normal physiological settings and during breast cancer progression. Importantly, the effects of several of these microenvironmental signals are mediated by the activities of the tumor suppressor protein kinases of the Hippo pathway. Canonically, Hippo protein kinases inhibit cellular growth through the phosphorylation and inactivation of the oncogenic transcriptional co-activator Yes-Associated Protein (YAP). This study defines an alternative mechanism whereby Hippo protein kinases induce growth arrest via the phosphorylation of the long isoform of Angiomotin (Amot130). Specifically, serum starvation is found to activate the Hippo protein kinase, Large Tumor Suppressor (LATS), which phosphorylates the adapter protein Amot130 at serine-175. Importantly, wild-type Amot130 potently inhibits mammary epithelial cell growth, unlike the Amot130 serine-175 to alanine mutant, which cannot be phosphorylated at this residue. The growth-arrested phenotype of Amot130 is likely a result of its mechanistic response to LATS signaling. Specifically, LATS activity promotes the association of Amot130 with the ubiquitin ligase Atrophin-1 Interacting Protein 4 (AIP4). As a consequence, the Amot130-AIP4 complex amplifies LATS tumor suppressive signaling by stabilizing LATS protein steady state levels via preventing AIP4-targeted degradation of LATS. Additionally, AIP4 binding to Amot130 leads to the ubiquitination and stabilization of Amot130. In turn, the Amot130-AIP4 complex signals the ubiquitination and degradation of YAP. This inhibition of YAP activity by Amot130 requires both AIP4 and the ability of Amot130 to be phosphorylated by LATS. Together, these findings significantly modify the current view that the phosphorylation of YAP by Hippo protein kinases is sufficient for YAP inhibition and cellular growth arrest. Based upon these results, the inhibition of cellular growth in the absence of serum more accurately involves the stabilization of Amot130 and LATS, which together inhibit YAP activity and mammary epithelial cell growth.