The present study aims to analyze the prevalence and risk factors of active pediculosis and to co... more The present study aims to analyze the prevalence and risk factors of active pediculosis and to compare the efficacy and sensitivity of the vacuum method with the comb method and the visual inspection with a magnifying glass in order to determine the best methodology to detect active pediculosis among schoolchildren from Paraná state. Each child was examined by the three methods in sequence and a playful activity was introduced to increase the children likelihood to participate in the study. Additionally, hair characteristics and other risk factors as sex, age, and area of living were take into consideration to measure epidemiological aspects. From a total of 358 schoolchildren from southern Brazil, overall pediculosis prevalence was 45.5%, while active pediculosis prevalence was 13.1%. Regarding active pediculosis, there was no statistical difference among sex. However, nine-year-old girls were most likely to have active pediculosis. The vacuum method was 5.96 and 11.29 times more e...
As maos favorecem a transmissao de patogenos. Assim, lava-las corretamente e com frequencia e fun... more As maos favorecem a transmissao de patogenos. Assim, lava-las corretamente e com frequencia e fundamental para a prevencao de doencas. Utilizando metodologias participativas e de pesquisa-acao, este estudo visou apresentar uma atividade que promovesse a educacao em saude a partir da correta lavagem das maos. O publico alvo foram criancas com idades entre quatro e onze anos, alem de seus pais. As intervencoes ocorreram em dois dias, baseando-se em praticas ludicas com uso de tinta guache, em uma escola publica de Araucaria. O aproveitamento dos participantes foi analisado durante as atividades por meio de perguntas orais. Ao todo, 145 criancas e aproximadamente 20 pais participaram da dinâmica, sendo que as criancas contribuiram ativamente, enquanto entre os pais houve hesitacao inicial. Apesar disso, ambos responderam as perguntas avaliativas de forma correta ao final da pratica. O projeto foi avaliado por professores da escola por meio de formularios e obteve como media 9,82 - o qu...
Bahiawas the last Brazilian state declared free of Chagas disease transmission by Triatoma infest... more Bahiawas the last Brazilian state declared free of Chagas disease transmission by Triatoma infestans in 2006. The program designed to control vector transmission of Chagas is currently active, and all potential triatomines collected by the Bahia State Department of Health officials are most frequently diagnosed as negative for Trypanosoma cruzi when analyzed by the conventional parasitological direct method. The aim of the current study was to investigate whether triatomines from Bahia are free of T. cruzi infection using a more sensitive diagnostic methodology, namely the kinetoplastid-DNA polymerase chain reaction (kDNA-PCR). With the help of health officials, 51 triatomines were analyzed from peridomicile areas within the central north region of the state of Bahia. The majority (60.8%) were Triatoma brasiliensis , 29.4% were Triatoma pseudomaculata , and 9.8% were unidentified nymphs. Only one insect tested potentially positive for T. cruzi by the conventional parasitological dir...
Background: Canine heartworm infections were frequently diagnosed in Brazil before the new millen... more Background: Canine heartworm infections were frequently diagnosed in Brazil before the new millennium. After the year 2000, the frequency of diagnosis showed a sharp decline; however, a few years later, new evidence indicated that the parasite was still present and that canine infection rates seemed to be increasing. Therefore, an updated survey of canine heartworm prevalence was conducted in several locations in south, southeast, and northeast Brazil. Methods: Dogs from 15 locations having previously reported a high prevalence of heartworm infection were included in the survey according to defined criteria, including the absence of treatment with a macrocyclic lactone for at least 1 year. Blood samples from 1531 dogs were evaluated by an in-clinic immunochromatography test kit (Witness® Heartworm, Zoetis, USA) for detection of Dirofilaria immitis antigen. At each location, epidemiologic data, including physical characteristics and clinical signs reported by owners or observed by veterinarians, were recorded on prepared forms for tabulation of results by location, clinical signs, and physical characteristics. Results: The overall prevalence of canine heartworm infection was 23.1%, with evidence of heartworm-infected dogs detected in all 15 locations studied. There was a tendency for higher prevalence rates in environmentally protected areas, despite some locations having less-than-ideal environmental temperatures for survival of vector mosquitoes. Among physical characteristics, it was noted that dogs with predominantly white hair coats and residing in areas with a high (≥20%) prevalence of heartworm were less likely to have heartworm infection detected by a commercial heartworm antigen test kit than were dogs with other coat colors. In general, dogs older than 2 years were more frequently positive for D. immitis antigen than were younger dogs. Clinical signs of heartworm infections were rare or owners were unable to detect them, and could not be used for reliable prediction of the presence of heartworm. Conclusions: These results indicate that the prevalence of D. immitis has increased in these areas of Brazil over the past few years. Small animal practitioners in these areas should include routine screening tests for heartworm infections in every dog's annual evaluation protocol and make sure to have uninfected dogs on prevention.
PREVALENCE OF FILARIOSIS IN DOGS TO THE BEACH COAST OF PARANÁ STATE BRAZIL: PROEMINENCE FOR Dirof... more PREVALENCE OF FILARIOSIS IN DOGS TO THE BEACH COAST OF PARANÁ STATE BRAZIL: PROEMINENCE FOR Dirofilaria immitis Heartwom disease, or dirofilariasis, is a worldwide disease, present particularly in beach coasts of the globe. The etiologic agent Dirofilaria immitis (Leidy, 1856) has as definite hosts dogs and wild canids and as intermediate hosts, or vectors, mosquitoes from the Culicidae family. In Brazil, specifically in the beach coast of São Paulo and Rio de Janeiro states, dirofilariasis may be present in up to 45% of the dogs. There is no official reports about the prevalence of heartworm disease in the state of Paraná. Therefore, the present research has the main objective of determining the prevalence of heartworm disease in the beach coast of Paraná. Once this data is available, veterinarians and the general population could adopt proper measures of treatment and control of this disease. The research included 11 distinct coast regions covering, strategically, the beach coast ...
Revista do Instituto de Medicina Tropical de São Paulo
This is an open-access article distributed under the terms of the Creative Commons Attribution Li... more This is an open-access article distributed under the terms of the Creative Commons Attribution License.
A Bahia foi o último estado brasileiro a ser declarado livre da transmissão da doença deChagas pe... more A Bahia foi o último estado brasileiro a ser declarado livre da transmissão da doença deChagas pelo Triatoma infestans em 2006. O programa designado para controle vetorial da transmissão da doença de Chagas está atualmente ativo, e os potenciais triatomíneos coletados por funcionários do Departamento da Saúde do Estado da Bahia são praticamente todos diagnosticados como negativos para Trypanosoma cruzi quando analisados pelo método parasitológico convencional direto. O objetivo deste estudo foi investigar se os triatomíneos da Bahia, de fato, não estão infectados por T. cruzi, utilizando-se, para isso, uma metodologia de diagnóstico mais sensível, como a reação em cadeia da polimerase do DNA do cinetoplasto (kDNA-PCR). Com a ajuda dos funcionários da área da saúde, foram analisados 51 triatomíneos provenientes de áreas do peridomicílio da região centro-norte do estado da Bahia.Dos insetos analisados, a maioria (60,8%) era Triatoma brasiliensis, 29,4% eram Triatoma pseudomaculata e 9...
The kinetoplast DNA of trypanosomatids encodes for encrypted genes that can only be translated af... more The kinetoplast DNA of trypanosomatids encodes for encrypted genes that can only be translated after a posttranscriptional processing event called mRNA editing. This RNA editing is of the urydylate (U)-insertion, (U)-deletion type and requires guide RNAs and a multiprotein complex called editosome. The pathway leading to annealing of the distinct mRNA/gRNA complexes and assembly with the editosome is still unknown. Because this type of editing is unique to trypanosomatids, deciphering of the pathway for better understanding of the editing mechanism will open doors for the discovery of new drug targets. Resumo O DNA do cinetoplasto dos tripanosomatideos codifica ge nes que são incompletos e que só irão gerar proteínas funcionais após a seqüência dos mRNAs ser modificada por um processo determinado edição do RNA. Esta edição insere ou remove uridinas (U) e é realizada por um complexo de proteínas chamado editossomo com o auxílio de RNA guias. A seqüência de eventos que leva ao pareame...
The most dramatic example of RNA editing is found in the mitochondria of trypanosomes. In these o... more The most dramatic example of RNA editing is found in the mitochondria of trypanosomes. In these organisms, U-insertions/deletions can create mRNAs that are twice as large as the gene that encodes them. Guide RNAs (gRNAs) that are complementary to short stretches of the mature message direct the precise placements of the U residues. The binding of gRNA to mRNA is a fundamental step in RNA editing and understanding the relative importance of the elements that confer affinity and specificity on this interaction is critical to our understanding of the editing process. In this study, we have analyzed the relative binding affinities of two different gRNA/mRNA pairs. The affinity of gA6-14 for its message (ATPase 6) is high, with an apparent K D in the 5-10 nM range. In contrast, gCYb-558 has a low affinity for its cognate mRNA. Deletion of the gRNA U-tail caused a significant reduction in the binding affinity for only the gCYb-558 pair, and was observed only under physiological magnesium conditions. These results indicate that the U-tail contribution can differ substantially between the different gRNA/mRNA pairs. In addition, our results suggest that the efficiency of gRNA/mRNA interaction is highly dependent on thermodynamic parameters determined by the local sequences and their adopted structures surrounding the anchor-binding site.
T. brucei survival relies on the expression of mitochondrial genes, most of which require RNA edi... more T. brucei survival relies on the expression of mitochondrial genes, most of which require RNA editing to become translatable. In trypanosomes, RNA editing involves the insertion and deletion of uridylates, a developmentally regulated process directed by guide RNAs (gRNAs) and catalyzed by the editosome, a complex of proteins. The pathway for mRNA/gRNA complex formation and assembly with the editosome is still unknown. Work from our laboratory has suggested that distinct mRNA/gRNA complexes anneal to form a conserved core structure that may be important for editosome assembly. The secondary structure for the apocytochrome b (CYb) pair has been previously determined and is consistant with our model of a three-helical structure. Here, we used cross-linking and solution structure probing experiments to determine the structure of the ATPase subunit 6 (A6) mRNA hybridized to its cognate gA6-14 gRNA in different stages of editing. Our results indicate that both unedited and partially edited A6/gA6-14 pairs fold into a three-helical structure similar to the previously characterized CYb/ gCYb-558 pair. These results lead us to conclude that at least two mRNA/gRNA pairs with distinct editing sites and distinct primary sequences fold to a three-helical secondary configuration that persists through the first few editing events.
Mitochondrial mRNA editing in Trypanosoma brucei requires the specific interaction of a guide RNA... more Mitochondrial mRNA editing in Trypanosoma brucei requires the specific interaction of a guide RNA with its cognate mRNA. Hundreds of gRNAs are involved in the editing process, each needing to target their specific editing domain within the target message. We hypothesized that the structure surrounding the mRNA target may be a limiting factor and involved in the regulation process. In this study, we selected four mRNAs with distinct target structures and investigated how sequence and structure affected efficient gRNA targeting. Two of the mRNAs, including the ATPase subunit 6 and ND7-550 (59 end of NADH dehydrogenase subunit 7) that have open, accessible anchor binding sites show very efficient gRNA targeting. Electrophoretic mobility shift assays indicate that the cognate gRNA for ND7-550 had 10-fold higher affinity for its mRNA than the A6 pair. Surface plasmon resonance studies indicate that the difference in affinity was due to a four-fold faster association rate. As expected, mRNAs with considerable structure surrounding the anchor binding sites were less accessible and had very low affinity for their cognate gRNAs. In vitro editing assays indicate that efficient pairing is crucial for gRNA directed cleavage. However, only the A6 substrate showed gRNA-directed cleavage at the correct editing site. This suggests that different gRNA/mRNA pairs may require different ''sets'' of accessory factors for efficient editing. By characterizing a number of different gRNA/mRNA interactions, we may be able to define a ''bank'' of RNA editing substrates with different putative chaperone and other co-factor requirements. This will allow the more efficient identification and characterization of transcript specific RNA editing accessory proteins.
Page 1. STRUCTURAL AND THERMODYNAMIC STUDIES OF THE ATPASE SUBUNIT 6 MRNA/GRNA COMPLEX IN TRYPANO... more Page 1. STRUCTURAL AND THERMODYNAMIC STUDIES OF THE ATPASE SUBUNIT 6 MRNA/GRNA COMPLEX IN TRYPANOSOMA BRUCEI By Larissa Reifur A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree ...
Bahia was the last Brazilian state declared free of Chagas disease transmission by Triatoma infes... more Bahia was the last Brazilian state declared free of Chagas disease transmission by Triatoma infestans in 2006. The program designed to control vector transmission of Chagas is currently active, and all potential triatomines collected by the Bahia State Department of Health officials are most frequently diagnosed as negative for Trypanosoma cruzi when analyzed by the conventional parasitological direct method. The aim of the current study was to investigate whether triatomines from Bahia are free of T. cruzi infection using a more sensitive diagnostic methodology, namely the kinetoplastid-DNA polymerase chain reaction (kDNA-PCR). With the help of health officials, 51 triatomines were analyzed from peridomicile areas within the central north region of the state of Bahia. The majority (60.8%) were Triatoma brasiliensis, 29.4% were Triatoma pseudomaculata, and 9.8% were unidentified nymphs. Only one insect tested potentially positive for T. cruzi by the conventional parasitological direct method, and 31.4% were positive for T. cruzi DNA by kDNA-PCR. Almost half the infected insects (41.9%) were T. brasiliensis, a species with high potential for T. cruzi transmission. These results demonstrate that the number of infected triatomines with high transmission potential of T. cruzi may be greater than expected in four localities in the state of Bahia.
O presente artigo tem como foco relatar e discutir a atividade realizada em uma escola da perifer... more O presente artigo tem como foco relatar e discutir a atividade realizada em uma escola da periferia da cidade de Araucária-PR. O objetivo da atividade foi transmitir os conhecimentos sobre a pediculose, com ênfase no combate e prevenção, e desmistificar informações que vêm do conhecimento popular referentes a estas temáticas. O teatro foi a metodologia aplicada e apresentada para um total de 145 crianças, do pré-escolar ao quinto ano dos anos iniciais, e para um grupo de dez a 20 responsáveis. A atividade e a interação com o público foram bastante satisfatórias, uma vez que as crianças e responsáveis expuseram seus conhecimentos tradicionais prévios e foi possível por meio de um “bate-papo” corrigir alguns saberes arraigados sempre fundamentando em informações científicas.
The present study aims to analyze the prevalence and risk factors of active pediculosis and to co... more The present study aims to analyze the prevalence and risk factors of active pediculosis and to compare the efficacy and sensitivity of the vacuum method with the comb method and the visual inspection with a magnifying glass in order to determine the best methodology to detect active pediculosis among schoolchildren from Paraná state. Each child was examined by the three methods in sequence and a playful activity was introduced to increase the children likelihood to participate in the study. Additionally, hair characteristics and other risk factors as sex, age, and area of living were take into consideration to measure epidemiological aspects. From a total of 358 schoolchildren from southern Brazil, overall pediculosis prevalence was 45.5%, while active pediculosis prevalence was 13.1%. Regarding active pediculosis, there was no statistical difference among sex. However, nine-year-old girls were most likely to have active pediculosis. The vacuum method was 5.96 and 11.29 times more e...
As maos favorecem a transmissao de patogenos. Assim, lava-las corretamente e com frequencia e fun... more As maos favorecem a transmissao de patogenos. Assim, lava-las corretamente e com frequencia e fundamental para a prevencao de doencas. Utilizando metodologias participativas e de pesquisa-acao, este estudo visou apresentar uma atividade que promovesse a educacao em saude a partir da correta lavagem das maos. O publico alvo foram criancas com idades entre quatro e onze anos, alem de seus pais. As intervencoes ocorreram em dois dias, baseando-se em praticas ludicas com uso de tinta guache, em uma escola publica de Araucaria. O aproveitamento dos participantes foi analisado durante as atividades por meio de perguntas orais. Ao todo, 145 criancas e aproximadamente 20 pais participaram da dinâmica, sendo que as criancas contribuiram ativamente, enquanto entre os pais houve hesitacao inicial. Apesar disso, ambos responderam as perguntas avaliativas de forma correta ao final da pratica. O projeto foi avaliado por professores da escola por meio de formularios e obteve como media 9,82 - o qu...
Bahiawas the last Brazilian state declared free of Chagas disease transmission by Triatoma infest... more Bahiawas the last Brazilian state declared free of Chagas disease transmission by Triatoma infestans in 2006. The program designed to control vector transmission of Chagas is currently active, and all potential triatomines collected by the Bahia State Department of Health officials are most frequently diagnosed as negative for Trypanosoma cruzi when analyzed by the conventional parasitological direct method. The aim of the current study was to investigate whether triatomines from Bahia are free of T. cruzi infection using a more sensitive diagnostic methodology, namely the kinetoplastid-DNA polymerase chain reaction (kDNA-PCR). With the help of health officials, 51 triatomines were analyzed from peridomicile areas within the central north region of the state of Bahia. The majority (60.8%) were Triatoma brasiliensis , 29.4% were Triatoma pseudomaculata , and 9.8% were unidentified nymphs. Only one insect tested potentially positive for T. cruzi by the conventional parasitological dir...
Background: Canine heartworm infections were frequently diagnosed in Brazil before the new millen... more Background: Canine heartworm infections were frequently diagnosed in Brazil before the new millennium. After the year 2000, the frequency of diagnosis showed a sharp decline; however, a few years later, new evidence indicated that the parasite was still present and that canine infection rates seemed to be increasing. Therefore, an updated survey of canine heartworm prevalence was conducted in several locations in south, southeast, and northeast Brazil. Methods: Dogs from 15 locations having previously reported a high prevalence of heartworm infection were included in the survey according to defined criteria, including the absence of treatment with a macrocyclic lactone for at least 1 year. Blood samples from 1531 dogs were evaluated by an in-clinic immunochromatography test kit (Witness® Heartworm, Zoetis, USA) for detection of Dirofilaria immitis antigen. At each location, epidemiologic data, including physical characteristics and clinical signs reported by owners or observed by veterinarians, were recorded on prepared forms for tabulation of results by location, clinical signs, and physical characteristics. Results: The overall prevalence of canine heartworm infection was 23.1%, with evidence of heartworm-infected dogs detected in all 15 locations studied. There was a tendency for higher prevalence rates in environmentally protected areas, despite some locations having less-than-ideal environmental temperatures for survival of vector mosquitoes. Among physical characteristics, it was noted that dogs with predominantly white hair coats and residing in areas with a high (≥20%) prevalence of heartworm were less likely to have heartworm infection detected by a commercial heartworm antigen test kit than were dogs with other coat colors. In general, dogs older than 2 years were more frequently positive for D. immitis antigen than were younger dogs. Clinical signs of heartworm infections were rare or owners were unable to detect them, and could not be used for reliable prediction of the presence of heartworm. Conclusions: These results indicate that the prevalence of D. immitis has increased in these areas of Brazil over the past few years. Small animal practitioners in these areas should include routine screening tests for heartworm infections in every dog's annual evaluation protocol and make sure to have uninfected dogs on prevention.
PREVALENCE OF FILARIOSIS IN DOGS TO THE BEACH COAST OF PARANÁ STATE BRAZIL: PROEMINENCE FOR Dirof... more PREVALENCE OF FILARIOSIS IN DOGS TO THE BEACH COAST OF PARANÁ STATE BRAZIL: PROEMINENCE FOR Dirofilaria immitis Heartwom disease, or dirofilariasis, is a worldwide disease, present particularly in beach coasts of the globe. The etiologic agent Dirofilaria immitis (Leidy, 1856) has as definite hosts dogs and wild canids and as intermediate hosts, or vectors, mosquitoes from the Culicidae family. In Brazil, specifically in the beach coast of São Paulo and Rio de Janeiro states, dirofilariasis may be present in up to 45% of the dogs. There is no official reports about the prevalence of heartworm disease in the state of Paraná. Therefore, the present research has the main objective of determining the prevalence of heartworm disease in the beach coast of Paraná. Once this data is available, veterinarians and the general population could adopt proper measures of treatment and control of this disease. The research included 11 distinct coast regions covering, strategically, the beach coast ...
Revista do Instituto de Medicina Tropical de São Paulo
This is an open-access article distributed under the terms of the Creative Commons Attribution Li... more This is an open-access article distributed under the terms of the Creative Commons Attribution License.
A Bahia foi o último estado brasileiro a ser declarado livre da transmissão da doença deChagas pe... more A Bahia foi o último estado brasileiro a ser declarado livre da transmissão da doença deChagas pelo Triatoma infestans em 2006. O programa designado para controle vetorial da transmissão da doença de Chagas está atualmente ativo, e os potenciais triatomíneos coletados por funcionários do Departamento da Saúde do Estado da Bahia são praticamente todos diagnosticados como negativos para Trypanosoma cruzi quando analisados pelo método parasitológico convencional direto. O objetivo deste estudo foi investigar se os triatomíneos da Bahia, de fato, não estão infectados por T. cruzi, utilizando-se, para isso, uma metodologia de diagnóstico mais sensível, como a reação em cadeia da polimerase do DNA do cinetoplasto (kDNA-PCR). Com a ajuda dos funcionários da área da saúde, foram analisados 51 triatomíneos provenientes de áreas do peridomicílio da região centro-norte do estado da Bahia.Dos insetos analisados, a maioria (60,8%) era Triatoma brasiliensis, 29,4% eram Triatoma pseudomaculata e 9...
The kinetoplast DNA of trypanosomatids encodes for encrypted genes that can only be translated af... more The kinetoplast DNA of trypanosomatids encodes for encrypted genes that can only be translated after a posttranscriptional processing event called mRNA editing. This RNA editing is of the urydylate (U)-insertion, (U)-deletion type and requires guide RNAs and a multiprotein complex called editosome. The pathway leading to annealing of the distinct mRNA/gRNA complexes and assembly with the editosome is still unknown. Because this type of editing is unique to trypanosomatids, deciphering of the pathway for better understanding of the editing mechanism will open doors for the discovery of new drug targets. Resumo O DNA do cinetoplasto dos tripanosomatideos codifica ge nes que são incompletos e que só irão gerar proteínas funcionais após a seqüência dos mRNAs ser modificada por um processo determinado edição do RNA. Esta edição insere ou remove uridinas (U) e é realizada por um complexo de proteínas chamado editossomo com o auxílio de RNA guias. A seqüência de eventos que leva ao pareame...
The most dramatic example of RNA editing is found in the mitochondria of trypanosomes. In these o... more The most dramatic example of RNA editing is found in the mitochondria of trypanosomes. In these organisms, U-insertions/deletions can create mRNAs that are twice as large as the gene that encodes them. Guide RNAs (gRNAs) that are complementary to short stretches of the mature message direct the precise placements of the U residues. The binding of gRNA to mRNA is a fundamental step in RNA editing and understanding the relative importance of the elements that confer affinity and specificity on this interaction is critical to our understanding of the editing process. In this study, we have analyzed the relative binding affinities of two different gRNA/mRNA pairs. The affinity of gA6-14 for its message (ATPase 6) is high, with an apparent K D in the 5-10 nM range. In contrast, gCYb-558 has a low affinity for its cognate mRNA. Deletion of the gRNA U-tail caused a significant reduction in the binding affinity for only the gCYb-558 pair, and was observed only under physiological magnesium conditions. These results indicate that the U-tail contribution can differ substantially between the different gRNA/mRNA pairs. In addition, our results suggest that the efficiency of gRNA/mRNA interaction is highly dependent on thermodynamic parameters determined by the local sequences and their adopted structures surrounding the anchor-binding site.
T. brucei survival relies on the expression of mitochondrial genes, most of which require RNA edi... more T. brucei survival relies on the expression of mitochondrial genes, most of which require RNA editing to become translatable. In trypanosomes, RNA editing involves the insertion and deletion of uridylates, a developmentally regulated process directed by guide RNAs (gRNAs) and catalyzed by the editosome, a complex of proteins. The pathway for mRNA/gRNA complex formation and assembly with the editosome is still unknown. Work from our laboratory has suggested that distinct mRNA/gRNA complexes anneal to form a conserved core structure that may be important for editosome assembly. The secondary structure for the apocytochrome b (CYb) pair has been previously determined and is consistant with our model of a three-helical structure. Here, we used cross-linking and solution structure probing experiments to determine the structure of the ATPase subunit 6 (A6) mRNA hybridized to its cognate gA6-14 gRNA in different stages of editing. Our results indicate that both unedited and partially edited A6/gA6-14 pairs fold into a three-helical structure similar to the previously characterized CYb/ gCYb-558 pair. These results lead us to conclude that at least two mRNA/gRNA pairs with distinct editing sites and distinct primary sequences fold to a three-helical secondary configuration that persists through the first few editing events.
Mitochondrial mRNA editing in Trypanosoma brucei requires the specific interaction of a guide RNA... more Mitochondrial mRNA editing in Trypanosoma brucei requires the specific interaction of a guide RNA with its cognate mRNA. Hundreds of gRNAs are involved in the editing process, each needing to target their specific editing domain within the target message. We hypothesized that the structure surrounding the mRNA target may be a limiting factor and involved in the regulation process. In this study, we selected four mRNAs with distinct target structures and investigated how sequence and structure affected efficient gRNA targeting. Two of the mRNAs, including the ATPase subunit 6 and ND7-550 (59 end of NADH dehydrogenase subunit 7) that have open, accessible anchor binding sites show very efficient gRNA targeting. Electrophoretic mobility shift assays indicate that the cognate gRNA for ND7-550 had 10-fold higher affinity for its mRNA than the A6 pair. Surface plasmon resonance studies indicate that the difference in affinity was due to a four-fold faster association rate. As expected, mRNAs with considerable structure surrounding the anchor binding sites were less accessible and had very low affinity for their cognate gRNAs. In vitro editing assays indicate that efficient pairing is crucial for gRNA directed cleavage. However, only the A6 substrate showed gRNA-directed cleavage at the correct editing site. This suggests that different gRNA/mRNA pairs may require different ''sets'' of accessory factors for efficient editing. By characterizing a number of different gRNA/mRNA interactions, we may be able to define a ''bank'' of RNA editing substrates with different putative chaperone and other co-factor requirements. This will allow the more efficient identification and characterization of transcript specific RNA editing accessory proteins.
Page 1. STRUCTURAL AND THERMODYNAMIC STUDIES OF THE ATPASE SUBUNIT 6 MRNA/GRNA COMPLEX IN TRYPANO... more Page 1. STRUCTURAL AND THERMODYNAMIC STUDIES OF THE ATPASE SUBUNIT 6 MRNA/GRNA COMPLEX IN TRYPANOSOMA BRUCEI By Larissa Reifur A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree ...
Bahia was the last Brazilian state declared free of Chagas disease transmission by Triatoma infes... more Bahia was the last Brazilian state declared free of Chagas disease transmission by Triatoma infestans in 2006. The program designed to control vector transmission of Chagas is currently active, and all potential triatomines collected by the Bahia State Department of Health officials are most frequently diagnosed as negative for Trypanosoma cruzi when analyzed by the conventional parasitological direct method. The aim of the current study was to investigate whether triatomines from Bahia are free of T. cruzi infection using a more sensitive diagnostic methodology, namely the kinetoplastid-DNA polymerase chain reaction (kDNA-PCR). With the help of health officials, 51 triatomines were analyzed from peridomicile areas within the central north region of the state of Bahia. The majority (60.8%) were Triatoma brasiliensis, 29.4% were Triatoma pseudomaculata, and 9.8% were unidentified nymphs. Only one insect tested potentially positive for T. cruzi by the conventional parasitological direct method, and 31.4% were positive for T. cruzi DNA by kDNA-PCR. Almost half the infected insects (41.9%) were T. brasiliensis, a species with high potential for T. cruzi transmission. These results demonstrate that the number of infected triatomines with high transmission potential of T. cruzi may be greater than expected in four localities in the state of Bahia.
O presente artigo tem como foco relatar e discutir a atividade realizada em uma escola da perifer... more O presente artigo tem como foco relatar e discutir a atividade realizada em uma escola da periferia da cidade de Araucária-PR. O objetivo da atividade foi transmitir os conhecimentos sobre a pediculose, com ênfase no combate e prevenção, e desmistificar informações que vêm do conhecimento popular referentes a estas temáticas. O teatro foi a metodologia aplicada e apresentada para um total de 145 crianças, do pré-escolar ao quinto ano dos anos iniciais, e para um grupo de dez a 20 responsáveis. A atividade e a interação com o público foram bastante satisfatórias, uma vez que as crianças e responsáveis expuseram seus conhecimentos tradicionais prévios e foi possível por meio de um “bate-papo” corrigir alguns saberes arraigados sempre fundamentando em informações científicas.
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