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In JoVE (3)
- Protocolo para infecções por dengue em mosquitos (A. aegypti) e Determinação Fenótipo Infecção
- Protocolo para a Criação Mosquito (A. gambiae)
- Protocolo para Infecções Plasmodium falciparum em mosquitos e Infecção Determinação Fenótipo
Other Publications (9)
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Articles by Suchismita Das in JoVE
JoVE General
Protocolo para infecções por dengue em mosquitos (A. aegypti) e Determinação Fenótipo Infecção
Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University
Uma vez que um gene é identificada como potencialmente refratário para o vírus da dengue, deve ser avaliado para o seu papel na prevenção de infecções virais dentro do mosquito. Este protocolo ilustra como a extensão das infecções por dengue de mosquitos podem ser ensaiadas. As técnicas para crescer o vírus em cultura, alimentando-se membrana de sangue os mosquitos humanos e assaying títulos viral no intestino médio do mosquito são demonstradas.
JoVE General
Protocolo para a Criação Mosquito (A. gambiae)
Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University
Este vídeo ilustra as técnicas gerais usadas para a retaguarda Anopheles gambiae em laboratório. Os métodos para cuidar dos mosquitos laboratório são demonstrados por todos os estágios do ciclo de vida do organismo a partir de larvas de pupas a sangue-alimentação adultos.
JoVE General
Protocolo para Infecções Plasmodium falciparum em mosquitos e Infecção Determinação Fenótipo
Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University
Uma vez que um gene é identificada como potencialmente refratário para a malária, deve ser avaliado pelo seu papel na prevenção de infecções Plasmodium dentro do mosquito. Este protocolo ilustra como a extensão de infecções plasmodium de mosquitos podem ser ensaiadas. As técnicas de preparação da cultura gametócitos, membrana alimentarem de sangue humano os mosquitos, e assaying títulos viral no intestino médio do mosquito são demonstradas.
Other articles by Suchismita Das on PubMed
Delinking of S Phase and Cytokinesis in the Protozoan Parasite Entamoeba Histolytica
The alternation of DNA replication in S phase and chromosome segregation in M phase is a hallmark in the cell cycle of most well-studied eukaryotes and ensures that the progeny do not have more than the normal complement of genes and chromosomes. An exception to this rule has been described in cancer cells that occasionally become polyploid as a result of failure to restrain S phase despite the failure to undergo complete mitosis. Here, we describe the cell division cycle of the human pathogen, Entamoeba histolytica, which routinely accumulates polyploid cells. We have studied DNA synthesis in freshly subcultured cells and show that, unlike most eukaryotes, Entamoeba cells reduplicate their genome several times before cell division occurs. Furthermore, polyploidy may occur without nuclear division so that single nuclei may contain 1-10 times or more genome contents. Multinucleated cells may also accumulate several genome contents in each nuclei of one cell. Thus, checkpoints that normally prevent DNA reduplication until after cytokinesis in most eukaryotes are not observed in E. histolytica.
Constitutive Association of Mcm2-3-5 Proteins with Chromatin in Entamoeba Histolytica
Eukaryotic cells duplicate their genome once and only once per cell cycle. Our earlier studies with the protozoan parasite, Entamoeba histolytica, have shown that genome reduplication may occur several times without nuclear or cellular division. The Mcm2-7 protein complex is required for licensing of DNA replication. In an effort to understand whether genome reduplication occurs due to absence or failure of the DNA replication licensing system, we analysed the function of Mcm2-3-5 proteins in E. histolytica. In this study, we have cloned E. histolytica (Eh) MCM2 and Eh MCM5 genes, while Eh MCM3 was cloned earlier. The sequence of Eh MCM2-3-5 genes is well conserved with other eukaryotic homologues. We have shown that Eh Mcm2,3 proteins are functional in Saccharomyces cerevisiae. Our studies in E. histolytica showed that Eh Mcm2-3-5 proteins are associated with chromatin constitutively in cycling cells and during arrest of DNA synthesis induced by serum starvation. Alternation of genome duplication with mitosis is regulated by association-dissociation of Mcm2-7 proteins with chromatin in other eukaryotes. Our results suggest that constitutive association of Mcm proteins with chromatin could be one of the reasons why genome reduplication occurs in E. histolytica.
The Cyst Wall of Entamoeba Invadens Contains Chitosan (deacetylated Chitin)
The cyst wall of Entamoeba invadens (Ei), a model for the human pathogen Entamoeba histolytica, contains chitin, which is a homopolymer of beta-1, 4-linked N-acetyl-glucosamine (GlcNAc). In fungi and in bacteria that make nodulation factors, chitin deacetylases make chitosan, which is a mixture of GlcNAc and glucosamine and so has a positive charge. The activity of an Ei chitin deacetylase was revealed by a 3-4-fold increase in released GlcNAc when deproteinated cyst walls were chemically acetylated prior to treatment with a commerical chitinase. Because this chitinase releases GlcNAc but not GlcN, increases in released GlcNAc after acetylation suggested the presence of chitosan in Ei cyst walls. Five putative Ei and Eh chitin deacetylase genes resembled those of fungi and bacteria. A predicted Eh chitin deacetylase matched closely the three-dimensional structure of a Bacillus subtilis peptiodglycan deacetylase. A recombinant Eh chitin deacetylase, expressed in Saccharomyces cerevisiae, deacetylated chitooligosaccharides in vitro. These results are consistent with the idea that Ei chitin deacetylases modify chitin to produce chitosan in the Ei cyst wall.
Continuous Exposure to Plasmodium Results in Decreased Susceptibility and Transcriptomic Divergence of the Anopheles Gambiae Immune System
Plasmodium infection has been shown to compromise the fitness of the mosquito vector, reducing its fecundity and longevity. However, from an evolutionary perspective, the impact of Plasmodium infection as a selective pressure on the mosquito is largely unknown.
Molecular Analysis of Photic Inhibition of Blood-feeding in Anopheles Gambiae
Anopheles gambiae mosquitoes exhibit an endophilic, nocturnal blood feeding behavior. Despite the importance of light as a regulator of malaria transmission, our knowledge on the molecular interactions between environmental cues, the circadian oscillators and the host seeking and feeding systems of the Anopheles mosquitoes is limited.
Trichomonas Transmembrane Cyclases Result from Massive Gene Duplication and Concomitant Development of Pseudogenes
Trichomonas vaginalis has an unusually large genome (approximately 160 Mb) encoding approximately 60,000 proteins. With the goal of beginning to understand why some Trichomonas genes are present in so many copies, we characterized here a family of approximately 123 Trichomonas genes that encode transmembrane adenylyl cyclases (TMACs).
Pathogenomics of Culex Quinquefasciatus and Meta-analysis of Infection Responses to Diverse Pathogens
The mosquito Culex quinquefasciatus poses a substantial threat to human and veterinary health as a primary vector of West Nile virus (WNV), the filarial worm Wuchereria bancrofti, and an avian malaria parasite. Comparative phylogenomics revealed an expanded canonical C. quinquefasciatus immune gene repertoire compared with those of Aedes aegypti and Anopheles gambiae. Transcriptomic analysis of C. quinquefasciatus genes responsive to WNV, W. bancrofti, and non-native bacteria facilitated an unprecedented meta-analysis of 25 vector-pathogen interactions involving arboviruses, filarial worms, bacteria, and malaria parasites, revealing common and distinct responses to these pathogen types in three mosquito genera. Our findings provide support for the hypothesis that mosquito-borne pathogens have evolved to evade innate immune responses in three vector mosquito species of major medical importance.
Transcriptomic and Functional Analysis of the Anopheles Gambiae Salivary Gland in Relation to Blood Feeding
The Anopheles gambiae salivary glands play a major role in malaria transmission and express a variety of bioactive components that facilitate blood-feeding by preventing platelet aggregation, blood clotting, vasodilatation, and inflammatory and other reactions at the probing site on the vertebrate host.
Engineered Anopheles Immunity to Plasmodium Infection
A causative agent of human malaria, Plasmodium falciparum, is transmitted by Anopheles mosquitoes. The malaria parasite is under intensive attack from the mosquito's innate immune system during its sporogonic development. We have used genetic engineering to create immune-enhanced Anopheles stephensi mosquitoes through blood meal-inducible expression of a transgene encoding the IMD pathway-controlled NF-kB Rel2 transcription factor in the midgut and fat-body tissue. Transgenic mosquitoes showed greater resistance to Plasmodium and microbial infection as a result of timely concerted tissue-specific immune attacks involving multiple effectors. The relatively weak impact of this genetic modification on mosquito fitness under laboratory conditions encourages further investigation of this approach for malaria control.
