RESUMO
MicroRNAs (miRNAs) are molecules that influence messenger RNA (mRNA) expression levels by binding to the 3' untranslated region (3' UTR) of target genes. Host miRNAs can influence flavivirus replication, either by inducing changes in the host transcriptome or by directly binding to viral genomes. The 3' UTR of the flavivirus genome is a conserved region crucial for viral replication. Cells might exploit this well-preserved region by generating miRNAs that interact with it, ultimately impacting viral replication. Despite significant efforts to identify miRNAs capable of arresting viral replication, the potential of all these miRNAs to interact with the flavivirus 3' UTR is still poorly characterised. In this context, bioinformatic tools have been proposed as a fundamental part of accelerating the discovery of interactions between miRNAs and the 3' UTR of viral genomes. In this study, we performed a computational analysis to reveal potential miRNAs from human and mosquito species that bind to the 3' UTR of flaviviruses. In humans, miR-6842 and miR-661 were found, while in mosquitoes, miR-9-C, miR-2945-5p, miR-11924, miR-282-5p, and miR-79 were identified. These findings open new avenues for studying these miRNAs as antivirals against flavivirus infections.
Assuntos
Regiões 3' não Traduzidas , Biologia Computacional , Flavivirus , Genoma Viral , MicroRNAs , MicroRNAs/genética , MicroRNAs/metabolismo , Regiões 3' não Traduzidas/genética , Flavivirus/genética , Humanos , Animais , Biologia Computacional/métodos , Replicação Viral/genética , Antivirais/farmacologia , Infecções por Flavivirus/virologia , Infecções por Flavivirus/genética , Culicidae/virologia , Culicidae/genéticaRESUMO
The fissure fill localities of southwest England and South Wales are well-known for preserving rich assemblages of predominantly small-bodied Late Triassic to Early Jurassic tetrapods, but many aspects of these assemblages remain contentious. The age of the Late Triassic fissures is disputed, with some lines of argument suggesting a latest Triassic (Rhaetian) age, whereas other evidence suggests they may be as old as Carnian. The fissures have been hypothesized by some workers to have formed on an archipelago, with island effects invoked to explain aspects of the assemblages such as the abundance of small-bodied species. Procolophonids were a successful group of Triassic parareptiles, best known from Early to early Late Triassic assemblages, but have only recently been described from one of the fissure fill sites (Ruthin) based upon fragmentary remains. Here, we describe new procolophonid specimens from another fissure (Cromhall) that represent at least six individuals of different sizes, with much of the skeleton represented including well-preserved skull material. The Cromhall procolophonid shows strong similarities to Late Triassic procolophonids from Scotland, Brazil and North America, but both autapomorphies and a unique character combination demonstrate that it represents a new species, which we name as Hwiccewyrm trispiculum gen. et sp. nov. Phylogenetic analysis places Hwiccewyrm in a derived clade within Leptopleuroninae, together with Leptopleuron, Hypsognathus, and Soturnia. The largest specimens of Hwiccewyrm demonstrate a body size that is similar to Leptopleuron and Hypsognathus, supporting other recent work that has questioned the insular dwarfism hypothesis for the fissure fill assemblages.
Assuntos
Dinossauros , Fósseis , Humanos , Animais , Filogenia , Crânio/anatomia & histologia , Cabeça , Brasil , Dinossauros/anatomia & histologiaRESUMO
Arboviruses are an important group of pathogens that cause diseases of medical and veterinary concern worldwide. The interactions of these viruses with their host cells are complex, and frequently, the coexistence of two different viruses in the same cell results in the inhibition of replication in one of the viruses, which is a phenomenon called viral interference. This phenomenon can be exploited to develop antiviral strategies. Insect cell lines persistently infected with arboviruses are useful models with which to study viral interference. In this work, a model of C6/36-HT cells (from Aedes albopictus mosquitoes) persistently infected with Dengue virus, serotype 2, was used. Viral interference was evaluated via plaque and flow cytometry assays. The presence of heterotypic interference against the other serotypes of the same virus and homologous interference against yellow fever virus was determined; however, this cell line did not display heterologous viral interference against Sindbis virus. The mechanisms responsible for viral interference have not been fully elucidated, but small RNAs could be involved. However, the silencing of Ago3, a key protein in the genome-derived P-element-induced wimpy testis pathway, did not alter the viral interference process, suggesting that viral interference occurs independent of this pathway.
RESUMO
The establishment of persistent dengue virus infection within the cells of the mosquito vector is an essential requirement for viral transmission to a new human host. The mechanisms involved in the establishment and maintenance of persistent infection are not well understood, but it has been suggested that both viral and cellular factors might play an important role. In the present work, we evaluated differential gene expression in Aedes albopictus cells acutely (C6/36-HT) and persistently infected (C6-L) with Dengue virus 2 by cDNA-AFLP. We observed that importin ß3 was upregulated in noninfected cells compared with C6-L cells. Using RT-qPCR and plaque assays, we observed that Dengue virus levels in C6-L cells essentially do not vary over time, and peak viral titers in acutely infected cells are observed at 72 and 120 h postinfection. The expression level of importin ß3 was higher in acutely infected cells than in persistently infected cells; this correlates with higher levels of NS5 in the nucleus of the cell. The differential pattern of importin ß3 expression between acute and persistent infection with Dengue virus 2 could be a mechanism to maintain viral infection over time, reducing the antiviral response of the cell and the viral replicative rate.
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Dengue manifestations range from a mild form, dengue fever (DF), to more severe forms such as dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). The ability of the host to present one of these clinical forms could be related to polymorphisms located in genes of the Toll-like receptors (TLRs) which activate the pro-inflammatory response. Therefore, the genotyping of single nucleotide genetic polymorphisms (SNPs) in TLR3 (rs3775291 and rs6552950), TLR4 (rs2737190, rs10759932, rs4986790, rs4986791, rs11536865, and rs10983755), TLR7 (rs179008 and rs3853839), and TLR8 (rs3764880, rs5741883, rs4830805, and rs1548731) was carried out in non-genetically related DHF patients, DF patients, and general population (GP) subjects. The SNPs were analyzed by real-time PCR by genotyping assays from Applied Biosystems®. The codominance model showed that dengue patients had a lower probability of presenting the TLR4-rs2737190-G/G genotype (odds ratio (OR) (95% CI) = 0.34 (0.14-0.8), p = 0.038). Dengue patients showed a lower probability of presenting TLR4-rs11536865-G/C genotype (OR (95% CI) = 0.19 (0.05-0.73), p = 0.0092) and had a high probability of presenting the TACG haplotype, but lower probability of presenting the TGCG haplotype in the TLR4 compared to GP individuals (OR (95% CI) = 0.55 (0.35-0.86), p = 0.0084). In conclusion, the TLR4-rs2737190-G/G and TLR4-rs11536865-G/C genotypes and TGCG haplotype were associated with protection from dengue.
Assuntos
Dengue/genética , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único , Receptor 3 Toll-Like/genética , Receptor 4 Toll-Like/genética , Receptor 7 Toll-Like/genética , Receptor 8 Toll-Like/genética , Adulto , Idoso , Alelos , Estudos de Casos e Controles , Dengue/sangue , Dengue/epidemiologia , Epidemias , Feminino , Genótipo , Haplótipos , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-IdadeRESUMO
The disease caused by the Zika virus (ZIKV) has positioned itself as one of the main public health problems in Mexico. One of the main reasons is it causes microcephaly and other birth defects. The transmission of ZIKV is through Aedes aegypti and Ae. albopictus mosquitoes, which are found in a larger space of the national territory. In addition, it can also be transmitted via blood transfusion, sexual relations, and maternal-fetal route. So far, there are no vaccines or specific treatments to deal with this infection. Currently, some new therapeutics such as small interfering RNAs (siRNAs) are able to regulate or suppress transcription in viruses. Therefore, in this project, an in silico siRNA was designed for the 3'UTR region of ZIKV via bioinformatics tools. The designed siRNA was synthesized and transfected into the C6/36 cell line, previously infected with ZIKV in order to assess the ability of the siRNA to inhibit viral replication. The designed siRNA was able to inhibit significantly (p < 0.05) ZIKV replication; this siRNA could be considered a potential therapeutic towards the disease that causes ZIKV and the medical problems generated.
Assuntos
Regiões 3' não Traduzidas , RNA Interferente Pequeno , RNA Viral/metabolismo , Replicação Viral/efeitos dos fármacos , Zika virus/fisiologia , Linhagem Celular , Humanos , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/farmacologia , RNA Viral/genética , Replicação Viral/genéticaRESUMO
The arthropod-borne flaviviruses are important human pathogens, and a deeper understanding of the virus-host cell interaction is required to identify cellular targets that can be used as therapeutic candidates. It is well reported that the flaviviruses hijack several cellular functions, such as exosome-mediated cell communication during infection, which is modulated by the delivery of the exosomal cargo of pro- or antiviral molecules to the receiving host cells. Therefore, to study the role of exosomes during flavivirus infections is essential, not only to understand its relevance in virus-host interaction, but also to identify molecular factors that may contribute to the development of new strategies to block these viral infections. This review explores the implications of exosomes in flavivirus dissemination and transmission from the vector to human host cells, as well as their involvement in the host immune response. The hypothesis about exosomes as a transplacental infection route of ZIKV and the paradox effect or the dual role of exosomes released during flavivirus infection are also discussed here. Although several studies have been performed in order to identify and characterize cellular and viral molecules released in exosomes, it is not clear how all of these components participate in viral pathogenesis. Further studies will determine the balance between protective and harmful exosomes secreted by flavivirus infected cells, the characteristics and components that distinguish them both, and how they could be a factor that determines the infection outcome.
Assuntos
Comunicação Celular , Exossomos/metabolismo , Infecções por Flavivirus/metabolismo , Flavivirus/metabolismo , Interações Hospedeiro-Patógeno , Animais , Vetores Aracnídeos/virologia , Dengue/metabolismo , Vesículas Extracelulares/metabolismo , Vesículas Extracelulares/virologia , Infecções por Flavivirus/transmissão , Humanos , Mosquitos Vetores/virologia , Carrapatos/virologia , Infecção por Zika virus/metabolismoRESUMO
Dengue virus (DENV) is an important flavivirus that is transmitted to humans by Aedes mosquitoes, where it can establish a persistent infection underlying vertical and horizontal transmission. However, the exact mechanism of persistent DENV infection is not well understood. Recently miR-927 was found to be upregulated in C6/36-HT cells at 57 weeks of persistent infection (C6-L57), suggesting its participation during this type of infection. The aim of this study was to determine the role of miR-927 during infection with DENV type 2. The results indicate an overexpression of miR-927 in C6-L57 cells and acutely infected cells according to the time of infection and the m.o.i. used. The downregulation of miR-927 in C6-L57 cells results in a reduction of both viral titre and viral genome copy number. The overexpression of miR-927 in C6-L40 and C6/36 cells infected at an m.o.i. of 0.1 causes an increase in both viral titre and viral genome copy number, suggesting a pro-viral activity of miR-927. In silico prediction analysis reveals target mRNAs for miR-927 are implicated in post-translational modifications (SUMO), translation factors (eIF-2B), the innate immune system (NKIRAS), exocytosis (EXOC-2), endocytosis (APM1) and the cytoskeleton (FLN). The expression levels of FLN were the most affected by both miR-927 overexpression and inhibition, and FLN was determined to be a direct target of miR-927 by a dual-luciferase gene reporter assay. FLN has been associated with the regulation of the Toll pathway and either overexpression or downregulation of miR-927 resulted in expression changes of antimicrobial peptides (Cecropins A and G, and Defensin D) involved in the Toll pathway response.
Assuntos
Aedes/genética , Aedes/virologia , Vírus da Dengue/genética , Dengue/virologia , MicroRNAs/genética , Animais , Linhagem Celular , Doenças Transmissíveis/genética , Doenças Transmissíveis/virologia , Genoma Viral/genética , Luciferases/genética , Replicação Viral/genéticaRESUMO
Anaphylaxis is a severe allergic reaction with a rapid onset and it is potentially life-threatening. Its clinical manifestations are varied; they may affect the skin, the cardiovascular system, the respiratory system, and the digestive system, among others. The treatment of choice, which is an intra-muscular injection of epinephrine (adrenaline), must be applied promptly. Therefore, being prepared to recognize it properly is of crucial importance. The objective of this clinical practice guide is to improve the knowledge of health professionals about anaphylaxis and, consequently, to optimize the treatment and long-term management of this reaction. This guide is adapted to the peculiarities of Latin America; especially in matters regarding the treatment. The need to introduce epinephrine auto-injectors in countries that don't have them yet is highlighted.
La anafilaxia es una reacción alérgica grave de instauración rápida y potencialmente mortal. Sus manifestaciones clínicas son muy variadas, pudiendo afectar la piel, el sistema cardiovascular, el aparato respiratorio y el digestivo, entre otros. El tratamiento de elección, mediante la inyección intramuscular de adrenalina, debe ser precoz. Por lo anterior, es vital estar preparados para reconocerla adecuadamente. El objetivo de la presente guía de actuación clínica es mejorar el conocimiento de los profesionales sanitarios sobre anafilaxia y, consecuentemente, optimizar el tratamiento y manejo a largo plazo de esta entidad. La guía está adaptada a las peculiaridades de América Latina, especialmente en los aspectos relativos al tratamiento. Se destaca la necesidad de introducir los autoinyectores de adrenalina en los países que no dispongan de ellos.
Assuntos
Anafilaxia , Guias de Prática Clínica como Assunto , Agonistas Adrenérgicos/administração & dosagem , Agonistas Adrenérgicos/uso terapêutico , Adulto , Algoritmos , Anafilaxia/diagnóstico , Anafilaxia/epidemiologia , Anafilaxia/etiologia , Anafilaxia/terapia , Reanimação Cardiopulmonar , Criança , Terapia Combinada , Gerenciamento Clínico , Vias de Administração de Medicamentos , Epinefrina/administração & dosagem , Epinefrina/uso terapêutico , Glucagon/administração & dosagem , Glucagon/uso terapêutico , Humanos , Testes Imunológicos , Educação de Pacientes como Assunto , Autoadministração , Vasoconstritores/administração & dosagem , Vasoconstritores/uso terapêuticoRESUMO
ABSTRACT Objectives To determine the differences between voiding symptoms obtained by open anamnesis (VS-Open) versus voiding symptoms obtained by directed anamnesis (VS-Directed) to predict voiding dysfunction in women. Materials and Methods Retrospective study of women with prior anti-incontinence surgery evaluated during 5 years. In a standardized clinical history taking, each patient was asked to answer question number five of the UDI-6 questionnaire ("Do you experience any difficulty emptying your bladder?"). If the answer was positive, the following voiding symptoms spontaneously described by the patient were documented: slow urine stream, straining to void, intermittent stream and feeling of incomplete bladder emptying, which were considered VS-Open. If the answer to this question was negative or if the patient had not reported the four voiding symptoms, she was asked in a directed manner about the presence of each o Ninety-one women are analyzed. Eighteen patients presented voiding dysfunction (19.8%), There was a statistical association between voiding dysfunction and the presence of any VS-Open (p = 0.037) and straining to void obtained by open anamnesis (p = 0.013). Sensitivity, specificity, PPV, NPV, positive likelihood ratio and negative likelihood ratio, respectively, were 44.4% and 27.8%, 80.8% and 94.5%, 36.3% and 55.6%, 85.5% and 84.1%, 2.324 and 5.129, and 0.686 and 0.764. There was no statistical association between voiding dysfunction and VS-Directed. Conclusions VS-Open may predict better voiding dysfunction than VS-Directed in women.
Assuntos
Humanos , Feminino , Adulto , Idoso , Idoso de 80 Anos ou mais , Transtornos Urinários/diagnóstico , Transtornos Urinários/fisiopatologia , Anamnese/métodos , Valores de Referência , Incontinência Urinária/cirurgia , Urodinâmica , Bexiga Urinária/fisiopatologia , Valor Preditivo dos Testes , Inquéritos e Questionários , Reprodutibilidade dos Testes , Estudos Retrospectivos , Pessoa de Meia-IdadeRESUMO
OBJECTIVES: To determine the differences between voiding symptoms obtained by open anamnesis (VS-Open) versus voiding symptoms obtained by directed anamnesis (VSDirected) to predict voiding dysfunction in women. MATERIALS AND METHODS: Retrospective study of women with prior anti-incontinence surgery evaluated during 5 years. In a standardized clinical history taking, each patient was asked to answer question number fi ve of the UDI-6 questionnaire ("Do you experience any difficulty emptying your bladder?"). If the answer was positive, the following voiding symptoms spontaneously described by the patient were documented: slow urine stream, straining to void, intermittent stream and feeling of incomplete bladder emptying, which were considered VS-Open. If the answer to this question was negative or if the patient had not reported the four voiding symptoms, she was asked in a directed manner about the presence of each of them, which were considered VS-Directed. Voiding dysfunction was considered the presence of a maximum fl ow ≤ 12 mL/s and/ or a postvoid residual > 100 mL. RESULTS: Ninety-one women are analyzed. Eighteen patients presented voiding dysfunction (19.8%), There was a statistical association between voiding dysfunction and the presence of any VS-Open (p = 0.037) and straining to void obtained by open anamnesis (p = 0.013). Sensitivity, specificity, PPV, NPV, positive likelihood ratio and negative likelihood ratio, respectively, were 44.4% and 27.8%, 80.8% and 94.5%, 36.3% and 55.6%, 85.5% and 84.1%, 2.324 and 5.129, and 0.686 and 0.764. There was no statistical association between voiding dysfunction and VS-Directed. CONCLUSIONS: VS-Open may predict better voiding dysfunction than VS-Directed in women.
Assuntos
Anamnese/métodos , Transtornos Urinários/diagnóstico , Transtornos Urinários/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Valores de Referência , Reprodutibilidade dos Testes , Estudos Retrospectivos , Inquéritos e Questionários , Bexiga Urinária/fisiopatologia , Incontinência Urinária/cirurgia , UrodinâmicaRESUMO
Exosomes are endocytic origin small-membrane vesicles secreted to the extracellular space by most cell types. Exosomes released from virus infected-cells can mediate the cell-to-cell communication to promote or modulate viral transmission. Dengue virus (DENV) is an arbovirus transmitted by Aedes mosquitoes bite to humans. Interestingly, the role of exosomes during the DENV infection in mammalian cells has already been described. However, little is known about exosomes derived from infected mosquito cells. Thus, the exosomes released from DENV-infected C6/36 cells were isolated, purified and analyzed using an antibody against the tetraspanin CD9 from human that showed cross-reactivity with the homologs to human CD9 found in Aedes albopictus (AalCD9). The exosomes from DENV infected cells were larger than the exosomes secreted from uninfected cells, contained virus-like particles, and they were able to infect naïve C6/36 cells, suggesting that exosomes are playing a role in virus dissemination.
Assuntos
Vírus da Dengue/fisiologia , Exossomos/metabolismo , Exossomos/virologia , Mosquitos Vetores/virologia , Aedes , Animais , Linhagem Celular , Dengue/metabolismo , Dengue/virologia , Difusão Dinâmica da Luz , Exossomos/imunologia , Humanos , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/imunologia , Proteínas de Insetos/metabolismo , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Mosquitos Vetores/classificação , Mosquitos Vetores/genética , Mosquitos Vetores/metabolismo , Filogenia , Tetraspaninas/química , Tetraspaninas/genética , Tetraspaninas/imunologia , Tetraspaninas/metabolismo , Replicação ViralRESUMO
Dengue viruses (DENV) are important arboviruses that can establish a persistent infection in its mosquito vector Aedes. Mosquitoes have a short lifetime in nature which makes trying to study the processes that take place during persistent viral infections in vivo. Therefore, C6/36 cells have been used to study this type of infection. C6/36 cells persistently infected with DENV 2 produce virions that cannot infect BHK -21 cells. We hypothesized that the following passages in mosquito cells have a deleterious impact on DENV fitness in vertebrate cells. Here, we demonstrated that the viral particles released from persistently infected cells were infectious to mosquito but not to vertebrate cells. This host restriction occurs at the replication level and is associated with several mutations in the DENV genome. In summary, our findings provide new information about viral replication fitness in a host-dependent manner.
Assuntos
Aedes/virologia , Vírus da Dengue/fisiologia , Especificidade de Hospedeiro , Mosquitos Vetores/virologia , Replicação Viral , Animais , Linhagem Celular , Dengue/virologia , Vírus da Dengue/genética , Genoma Viral , Mosquitos Vetores/crescimento & desenvolvimentoRESUMO
Human astrovirus (HAstV) constitutes a major cause of acute gastroenteritis in children. The viral 5' and 3' untranslated regions (UTR) have been involved in the regulation of several molecular mechanisms. However, in astrovirues have been less characterized. Here, we analyzed the secondary structures of the 5' and 3' UTR of HAstV, as well as their putative target sites that might be recognized by cellular factors. To our knowledge, this is the first bioinformatic analysis that predicts the HAstV 5' UTR secondary structure. The analysis showed that both the UTR sequence and secondary structure are highly conserved in all HAstVs analyzed, suggesting their regulatory role of viral activities. Notably, the UTRs of HAstVs contain putative binding sites for the serine/arginine-rich factors SRSF2, SRSF5, SRSF6, SRSF3, and the multifunctional hnRNPE2 protein. More importantly, putative binding sites for PTB were localized in single-stranded RNA sequences, while hnRNPE2 sites were localized in double-stranded sequence of the HAstV 5' and 3' UTR structures. These analyses suggest that the combination of SRSF proteins, hnRNPE2 and PTB described here could be involved in the maintenance of the secondary structure of the HAstVs, possibly allowing the recruitment of the replication complex that selects and recruits viral RNA replication templates.
Assuntos
Simulação por Computador , Mamastrovirus/genética , Proteínas/metabolismo , Regiões não Traduzidas/genética , Sequência de Bases , Sítios de Ligação , Conformação de Ácido NucleicoRESUMO
Here, we report for the first time the circulation of dengue virus type 1 (DENV-1) belonging to the lineage IV of genotype V (African American genotype) based on phylogenetic analysis of nucleotide sequences from 10 DENV-1-positive samples obtained in Mexico between 2012 and 2014. Our data revealed that the lineages III and IV of DENV-1 genotype V were found circulating during the same period, probably explaining the rise in the number of cases of severe dengue during that period.
Assuntos
Vírus da Dengue/genética , Genótipo , Filogenia , RNA Viral/genética , Dengue Grave/epidemiologia , Adolescente , Adulto , Criança , Vírus da Dengue/classificação , Vírus da Dengue/isolamento & purificação , Evolução Molecular , Feminino , Efeito Fundador , Variação Genética , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Epidemiologia Molecular , Filogeografia , Dengue Grave/diagnóstico , Dengue Grave/patologia , Dengue Grave/virologiaRESUMO
Dengue virus (DENV) is an arbovirus, which replicates in the endoplasmic reticulum. Although replicative cycle takes place in the cytoplasm, some viral proteins such as NS5 and C are translocated to the nucleus during infection in mosquitoes and mammalian cells. To localized viral proteins in DENV-infected C6/36 cells, an immunofluorescence (IF) and immunoelectron microscopy (IEM) analysis were performed. Our results indicated that C, NS1, NS3 and NS5 proteins were found in the nucleus of DENV-infected C6/36 cells. Additionally, complex structures named strand-like structures (Ss) were observed in the nucleus of infected cells. Interestingly, the NS5 protein was located in these structures. Ss were absent in mock-infected cells, suggesting that DENV induces their formation in the nucleus of infected mosquito cells.
Assuntos
Culicidae/virologia , Vírus da Dengue/ultraestrutura , Dengue/virologia , Proteínas não Estruturais Virais/ultraestrutura , Animais , Linhagem Celular , Núcleo Celular/ultraestrutura , Núcleo Celular/virologia , Retículo Endoplasmático/ultraestrutura , Retículo Endoplasmático/virologia , Humanos , Camundongos Endogâmicos BALB C , RNA Helicases/ultraestrutura , Serina Endopeptidases/ultraestrutura , Replicação ViralRESUMO
This study was designed to examine the effects of lyophilized red delicious apple peel (RDP) on the action potentials (APs) and the input resistance-threshold current relationship. The experiments were performed on isolated papillary heart muscles from healthy male rats, healthy male rats treated with RDP, diabetic male rats, and diabetic male rats treated with RDP. The preparation was superfused with oxygenated Tyrode's solution at 37°C. The stimulation and the recording of the APs, the input resistance, and the threshold current were made using conventional electrophysiological methods. The RDP presented no significant effect in normal rats. Equivalent doses in diabetic rats reduced the APD and ARP. The relationship between input resistance and threshold current established an inverse correlation. The results indicate the following: (1) The functional structure of the cardiac ventricular syncytium in healthy rats is heterogeneous, in terms of input resistance and threshold current. Diabetes further accentuates the heterogeneity. (2) As a consequence, conduction block occurs and increases the possibility of reentrant arrhythmias. (3) These modifications in the ventricular syncytium, coupled with the increase in the ARP, are the adequate substrate so that, with diabetes, the heart becomes more arrhythmogenic. (4) RDP decreases the APD, the ARP, and most syncytium irregularity caused by diabetes.
Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/fisiopatologia , Coração/fisiopatologia , Malus/química , Extratos Vegetais/farmacologia , Potenciais de Ação , Animais , Arritmias Cardíacas/metabolismo , Glicemia/análise , Peso Corporal , Frutas/química , Hemoglobinas Glicadas/análise , Coração/efeitos dos fármacos , Soluções Isotônicas , Masculino , Músculos Papilares/metabolismo , Ratos , TemperaturaRESUMO
Mosquito-borne flaviviruses are important pathogens for humans, and the detection of two or more flaviviruses cocirculating in the same geographic area has often been reported. However, the epidemiological impact remains to be determined. Mosquito-borne flaviviruses are primarily transmitted through Aedes and Culex mosquitoes; these viruses establish a life-long or persistent infection without apparent pathological effects. This establishment requires a balance between virus replication and the antiviral host response. Viral interference is a phenomenon whereby one virus inhibits the replication of other viruses, and this condition is frequently associated with persistent infections. Viral interference and persistent infection are determined by several factors, such as defective interfering particles, competition for cellular factors required for translation/replication, and the host antiviral response. The interaction between two flaviviruses typically results in viral interference, indicating that these viruses share common features during the replicative cycle in the vector. The potential mechanisms involved in these processes are reviewed here.
Assuntos
Culicidae/fisiologia , Culicidae/virologia , Flavivirus/fisiologia , Interações Hospedeiro-Patógeno , Interferência Viral , Animais , Infecções por Flavivirus/transmissão , Infecções por Flavivirus/virologia , Humanos , Interferência de RNA , RNA Interferente Pequeno/genéticaRESUMO
The increasing number of dengue virus (DENV) genome sequences available allows identifying the contributing factors to DENV evolution. In the present study, the codon usage in serotypes 1-4 (DENV1-4) has been explored for 3047 sequenced genomes using different statistics methods. The correlation analysis of total GC content (GC) with GC content at the three nucleotide positions of codons (GC1, GC2, and GC3) as well as the effective number of codons (ENC, ENCp) versus GC3 plots revealed mutational bias and purifying selection pressures as the major forces influencing the codon usage, but with distinct pressure on specific nucleotide position in the codon. The correspondence analysis (CA) and clustering analysis on relative synonymous codon usage (RSCU) within each serotype showed similar clustering patterns to the phylogenetic analysis of nucleotide sequences for DENV1-4. These clustering patterns are strongly related to the virus geographic origin. The phylogenetic dependence analysis also suggests that stabilizing selection acts on the codon usage bias. Our analysis of a large scale reveals new feature on DENV genomic evolution.
Assuntos
Códon/genética , Vírus da Dengue/genética , Evolução Molecular , Filogenia , Composição de Bases , Sequência de Bases , Dengue/genética , Dengue/virologia , Genoma Viral , Humanos , MutaçãoRESUMO
Dengue virus (DENV) is the causative agent of the most important mosquito-borne viral disease, which is endemic to over 100 countries in tropical and subtropical areas of the world. It is transmitted to humans by Aedes mosquitoes. The first step in the viral infection of host cells is virion attachment to the plasma membrane, which is mediated by specific surface molecules. There are several molecules that participate in DENV infection of mosquitoes, but only a few have been identified. In this work, we co-purified 4 proteins from C6/36 cells using a recombinant DENV 4 E protein and identified them as 70 kDa Heat Shock and 70 kDa Heat Shock cognate proteins (HSP70/HSc70), Binding immunoglobulin protein (BiP), Thioredoxin/protein disulphide isomerase (PDI), and 44 kDa Endoplasmic reticulum resident protein (ERp44) via matrix-assisted laser desorption/ionisation time of flight (Maldi-ToF) analysis. Using immunofluorescence and flow cytometry assays, we observed re-localisation of HSP70/HSc70 and, to a lesser extent, BiP to the plasma membrane under stress conditions, such as during DENV infection. By performing binding and infection assays independently, we found that all 4 proteins participate in both processes, but to differing extents: HSP70/HSc70 is the most critical component, while ERp44 is less important. Viral infection was not inhibited when the cells were incubated with antibodies against all of the surface proteins after virus binding, which suggests that DENV entry to C6/36 cells is mediated by these proteins at the same step and not sequentially.