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Artigos de revistas sobre o assunto "Vector / intermediate host"
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Choi, Vivian W., Douglas M. McCarty e R. Jude Samulski. "Host Cell DNA Repair Pathways in Adeno-Associated Viral Genome Processing". Journal of Virology 80, n.º 21 (1 de novembro de 2006): 10346–56. http://dx.doi.org/10.1128/jvi.00841-06.
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ABSTRACT Recentstudies have shown that wild-type and recombinant adeno-associated virus (AAV and rAAV) genomes persist in human tissue predominantly as double-stranded (ds) circular episomes derived from input linear single-stranded virion DNA. Using self-complementary recombinant AAV (scAAV) vectors, we generated intermediates that directly transition to ds circular episomes. The scAAV genome ends are palindromic hairpin-structured terminal repeats, resembling a double-stranded break repair intermediate. Utilizing this substrate, we found cellular DNA recombination and repair factors to be essential for generating circular episomal products. To identify the specific cellular proteins involved, the scAAV circularization-dependent vector was used as a reporter in 19 mammalian DNA repair-deficient cell lines. The results show that RecQ helicase family members (BLM and WRN), Mre11 and NBS1 of the Mre11-Rad50-Nbs1 (MRN) complex, and ATM are required for efficient scAAV genome circularization. We further demonstrated that the scAAV genome requires ATM and DNA-PKCS, but not NBS1, to efficiently convert to a circular form in nondividing cells in vivo using transgenic mice. These studies identify specific pathways involved for further elucidating viral and cellular mechanisms of DNA maintenance important to the viral life cycle and vector utilizations.
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Watkins, Raychel, Suzanne Moshier e Aelita Pinter. "Parasites of Small Mammals in Grand Teton National Park: Babesia and Hepatozoon". UW National Parks Service Research Station Annual Reports 20 (1 de janeiro de 1996): 95–99. http://dx.doi.org/10.13001/uwnpsrc.1996.3295.
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Babesia microti, a parasitic protozoan, is endemic in the Microtus montanus of Grand Teton National Park. It is transmitted by the tick Ixodes eastoni and reproduces in the erythrocytes of its vole host. A second protozoan parasite, Hepatozoon sp., which is widespread in small mammals in Europe, is also found in reptiles throughout the world. The record of Hepatozoon in North American small mammals is not extensive. Hepatozoon, unlike Babesia, may be a two-host or a three-host parasite. Also unlike Babesia, for which the intermediate host is always a tick, the intermediate host of Hepatozoon may be a tick, a mite, a flea, or a mosquito. The method of transmission by the vector also differs in the two parasites. Babesia is transmitted in the tick's saliva when it bites, whereas Hepatozoon infection requires the vertebrate host to ingest a vector. In our 1996 studies, we sought more data on these two parasites. The objectives for 1996 focused on Hepatozoon: to sample specific populations of M. montanus, in which we have previously documented Hepatozoon infections; to determine whether differences exist in the infection rates at different study sites in the park; and to search for any additional vectors of Hepatozoon sp. infections in M. montanus by examining ectoparasites. These studies contributed to our long-term objectives of documenting the effects and cost of parasitism on M. montanus populations.
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Moshier, Suzanne, Raychel Watkins e Aelita Pinter. "Parasites of Small Mammals in Grand Teton National Park: Babesia and Hepatozoon". UW National Parks Service Research Station Annual Reports 19 (1 de janeiro de 1995): 67–72. http://dx.doi.org/10.13001/uwnpsrc.1995.3249.
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The role of parasitism, whether macro- or microparasites, and whether endo- or ectoparasites, in the demographic machinery of microtines is poorly understood. In a review of the parasites of Microtus, Timm (1985) lists no protozoan endoparasites whatsoever for this genus and observes that one of the most challenging and fruitful directions of future research with Microtus will be the statistical quantification of the cost of parasitism. Babesia microti, a parasitic protozoan, is transmitted by a tick vector and reproduces in the erythrocytes of its mammalian host. Initially, Babesia was thought to be restricted to small mammals, however, in 1970 the first human cases were diagnosed in residents of Nantucket Island, Massachusetts (Western et al. 1970). In the United States, human babesiosis is caused by B. microti. As hunians insert themselves into places where they have historically been present only occasionally, they often contract new diseases. A second protozoan parasite, Hepatozoon sp., which is widespread in small mammals in Europe, is also found in reptiles throughout the world. The record of Hepatozoon in North American small mammals is not extensive. Like Babesia, Hepatozoon is a two-host parasite. Unlike Babesia, for which the intermediate host is always a tick, the intermediate host of Hepatozoon may be a tick, a mite, a flea, or a mosquito. The method of transmission by the vector also differs in the two parasites. Babesia is transmitted in the tick's saliva when it bites, whereas Hepatozoon infection requires the vertebrate host to swallow the vector. In our 1995 studies, we sought more data on these two parasites. The objectives for 1995 were: to sample specific populations of M. montanus, in which we have previously documented Hepatozoon infections, to determine whether there were differences in the infection rates at different study sites in the park, and to search for any additional vectors of Hepatozoon sp. infections in M. montanus by examining ectoparasites. Our long-term objectives are to document the effects and cost of parasitism on M. montanus populations.
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Burattini, Marcelo N., Francisco A. B. Coutinho, Luis F. Lopez e Eduardo Massad. "Modelling the Dynamics of Leishmaniasis Considering Human, Animal Host and Vector Populations". Journal of Biological Systems 06, n.º 04 (dezembro de 1998): 337–56. http://dx.doi.org/10.1142/s0218339098000224.
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Some of the vector-borne infections with public health importance involve an animal reservoir. This work describes, through a compartimental model, the dynamics of leishmaniasis considering the interactions between the three populations involved, namely the sandfly, the domestic dog (as the principal intermediate host), and the human population. An expression for the Basic Reproduction Ratio (R0), which takes into account the time delay representing the extrinsic incubation period of the parasite in the vector, is presented. Numerical simulation, equilibrium and stability analysis provided insights into the transmission dynamics of the infection that can help in the design of control strategies.
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Svinin, Anton Olegovich, I. V. Bashinskiy, S. N. Litvinchuk, L. A. Neymark, A. Yu Ivanov, O. A. Ermakov, A. A. Vedernikov e A. Dubois. "A Mollusk Planorbarius corneus is an Intermediate Host of the Infectious Agent of Rostand’s «Anomaly P» in Green Frogs". Russian Journal of Herpetology 26, n.º 6 (15 de dezembro de 2019): 349–53. http://dx.doi.org/10.30906/1026-2296-2019-26-6-349-353.
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Here we present the first new data about the mysterious «anomaly P» of green frogs (genus Pelophylax) in about 50 years. We established that the gastropod Planorbarius corneus could be an intermediate host (or vector) of the infectious agent of the anomaly P. Symmetrical cases of polydactyly, the anomaly «cross» and heavy cases of the anomaly P, which were previously found in natural populations in the European part of Russia and recently obtained in laboratory, can be caused by this infectious agent. As the most probable cause, we assume a species of trematodes, for which the first intermediate host is P. corneus, from which they infest tadpoles of green frogs.
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Stone, Chris M., Samantha R. Schwab, Dina M. Fonseca e Nina H. Fefferman. "Human movement, cooperation and the effectiveness of coordinated vector control strategies". Journal of The Royal Society Interface 14, n.º 133 (agosto de 2017): 20170336. http://dx.doi.org/10.1098/rsif.2017.0336.
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Vector-borne disease transmission is often typified by highly focal transmission and influenced by movement of hosts and vectors across different scales. The ecological and environmental conditions (including those created by humans through vector control programmes) that result in metapopulation dynamics remain poorly understood. The development of control strategies that would most effectively limit outbreaks given such dynamics is particularly urgent given the recent epidemics of dengue, chikungunya and Zika viruses. We developed a stochastic, spatial model of vector-borne disease transmission, allowing for movement of hosts between patches. Our model is applicable to arbovirus transmission by Aedes aegypti in urban settings and was parametrized to capture Zika virus transmission in particular. Using simulations, we investigated the extent to which two aspects of vector control strategies are affected by human commuting patterns: the extent of coordination and cooperation between neighbouring communities. We find that transmission intensity is highest at intermediate levels of host movement. The extent to which coordination of control activities among neighbouring patches decreases the prevalence of infection is affected by both how frequently humans commute and the proportion of neighbouring patches that commits to vector surveillance and control activities. At high levels of host movement, patches that do not contribute to vector control may act as sources of infection in the landscape, yet have comparable levels of prevalence as patches that do cooperate. This result suggests that real cooperation among neighbours will be critical to the development of effective pro-active strategies for vector-borne disease control in today's commuter-linked communities.
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Verneau, Olivier, Sirine Melliti, Latifa Kimdil, El Hassan El Mouden, Mohamed Sghaier Achouri e Rachid Rouag. "Molecular Phylogenies of Leeches and Haemoparasites Infecting Freshwater Turtles in Aquatic Ecosystems of Northern Africa Suggest Phylogenetic Congruence between Placobdella costata Sensu Lato and Haemogregarina stepanowi Sensu Lato". Microorganisms 11, n.º 6 (15 de junho de 2023): 1584. http://dx.doi.org/10.3390/microorganisms11061584.
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Haemogregarines are blood parasites with a life-cycle involving a vertebrate as the intermediate host and an invertebrate as the definitive host and vector. Extensive phylogenetic investigations based on 18S-rRNA gene sequences have shown that Haemogregarina stepanowi (Apicomplexa: Haemogregarinidae) is able to infest a large diversity of freshwater turtle species, including the European pond turtle Emys orbicularis, the Sicilian pond turtle Emys trinacris, the Caspian turtle Mauremys caspica, the Mediterranean pond turtle Mauremys leprosa, and the Western Caspian turtle Mauremys rivulata, among others. From the same molecular markers, H. stepanowi is further considered to be a complex of cryptic species predisposed to infect the same host species. While Placobdella costata is known to be the unique vector of H. stepanowi, it is only recently that independent lineages within P. costata have been illustrated—suggesting the presence of at least five unique leech species across Western Europe. The aims of our study were therefore to investigate from mitochondrial markers (COI) the genetic diversity within haemogregarines and leeches infecting freshwater turtles of the Maghreb, in order to identify processes of parasite speciation. We showed that H. stepanowi consists of at least five cryptic species in the Maghreb, while two Placobella species were identified in the same area. Although an Eastern–Western speciation pattern was apparent for both leeches and haemogregarines, we cannot make definitive conclusions regarding co-speciation patterns between parasites and vectors. However, we cannot reject the hypothesis of a very strict host–parasite specificity within leeches.
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Portet, Anaïs, Eve Toulza, Ana Lokmer, Camille Huot, David Duval, Richard Galinier e Benjamin Gourbal. "Experimental Infection of the Biomphalaria glabrata Vector Snail by Schistosoma mansoni Parasites Drives Snail Microbiota Dysbiosis". Microorganisms 9, n.º 5 (18 de maio de 2021): 1084. http://dx.doi.org/10.3390/microorganisms9051084.
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Host-parasite interaction can result in a strong alteration of the host-associated microbiota. This dysbiosis can affect the fitness of the host; can modify pathogen interaction and the outcome of diseases. Biomphalaria glabrata is the snail intermediate host of the trematode Schistosoma mansoni, the agent of human schistosomiasis, causing hundreds of thousands of deaths every year. Here, we present the first study of the snail bacterial microbiota in response to Schistosoma infection. We examined the interplay between B. glabrata, S. mansoni and host microbiota. Snails were infected and the microbiota composition was analysed by 16S rDNA amplicon sequencing approach. We demonstrated that the microbial composition of water did not affect the microbiota composition. Then, we characterised the Biomphalaria bacterial microbiota at the individual scale in both naive and infected snails. Sympatric and allopatric strains of parasites were used for infections and re-infections to analyse the modification or dysbiosis of snail microbiota in different host-parasite co-evolutionary contexts. Concomitantly, using RNAseq, we investigated the link between bacterial microbiota dysbiosis and snail anti-microbial peptide immune response. This work paves the way for a better understanding of snail/schistosome interaction and should have critical consequences in terms of snail control strategies for fighting schistosomiasis disease in the field.
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Velusamy, R., A. Latchumikanthan e M. K. Vijayasarathi. "The Lesser Mealworm Beetle (Alphitobius diaperinus) as an Intermediate Host for Poultry Tapeworm Raillietina cesticillus". UTTAR PRADESH JOURNAL OF ZOOLOGY 44, n.º 14 (20 de julho de 2023): 72–77. http://dx.doi.org/10.56557/upjoz/2023/v44i143560.
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Tapeworms are a widespread and recurrent problem in intensive chicken rearing and are transmitted by various types of invertebrate hosts dwelling in poultry litter. The mealworm beetle, Alphitobius diaperinus is the major pest in poultry litter and acts as an intermediate host for poultry tapeworms. Beetles collected from a poultry farm with suspected tapeworm infection were examined for the presence of the metacestode stage of the parasite. A total of 713 beetles were collected to study the vector potentiality. Out of these, 208 beetles (29.17%) were found to harbor cysticercoids of Railietina cesticillus. The percentage of cysticercoid infection in beetles was 33.42 and 24.78% respectively in two different surveys in a year. The beetles harboring the cysticercoids were identified as Alphitobius diaperinus, which may be a natural intermediate host for poultry tapeworm, Railietina cesticillus. The results of this study will help to formulate suitable control measures against the lesser mealworm beetles.
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Otahal, Alexander, Renate Fuchs, Faisal A. Al-Allaf e Dieter Blaas. "Release of Vesicular Stomatitis Virus Spike Protein G-Pseudotyped Lentivirus from the Host Cell Is Impaired upon Low-Density Lipoprotein Receptor Overexpression". Journal of Virology 89, n.º 22 (2 de setembro de 2015): 11723–26. http://dx.doi.org/10.1128/jvi.01869-15.
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Production of a vesicular stomatitis virus spike protein G (VSVG)-pseudotyped lentiviral expression vector in HEK293 cells decreased on overexpression of low-density lipoprotein receptor (LDLR) but not that of ICAM1 or TfR1. Reverse transcription-quantitative PCR (RT-qPCR) revealed a reduction in vector RNA as a function of LDLR expression. Decreased syncytium formation suggested diminished surface expression of VSVG. Intracellular VSVG granules colocalized with LDLR, ER-Golgi intermediate compartment protein 53 (ERGIC53), LAMP2, and vimentin but not with GM130 or calnexin, suggesting that VSVG interacts with LDLR within the ERGIC, resulting in rerouting into the aggresome/autophagosome pathway.
Teses / dissertações sobre o assunto "Vector / intermediate host"
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Jaquet, Mathilde. "Le microbiote des hôtes intermédiaires escargots et des moustiques vecteurs de zoonoses sous contraintes génétiques et environnementales : une approche de la capacité vectorielle". Electronic Thesis or Diss., Perpignan, 2024. http://www.theses.fr/2024PERP0032.
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Face à la forte augmentation des émergence et ré-émergences de maladies infectieuses au niveau mondial, il est crucial de comprendre les facteurs impliqués dans ces événements. Parmi ceux-ci, la ressource alimentaire et le microbiote apparaissent centraux dans le triptyque composé de l’hôte, des pathogènes qu’il transmet et de l’environnement. Ainsi, les travaux présentés dans cette thèse ont eu pour objectif d’identifier les liens entre facteurs environnementaux biotiques et abiotiques, microbiote et compétence vectorielle chez des mollusques et des arthropodes vecteurs de zoonoses. Ces recherches ont permis d’accroître les connaissances sur les communautés bactériennes appartenant au microbiote de populations naturelles de Bulinus truncatus et de Galba truncatula; ainsi que d’étudier l’influence des facteurs environnementaux et de la génétique sur ces dernières. Elles ont également permis d’évaluer le lien entre ressource alimentaire végétale et compétence vectorielle de populations de laboratoire d’Aedes albopictus. Ces études apportent des éléments nouveaux et pertinents pour mieux comprendre les interactions entre environnement, microbiote et compétence vectorielle des hôtes, offrant ainsi des perspectives pour la gestion des maladies infectieuses/ou des zones à risques d’émergenceIn light of the significant increase in the emergence and re-emergence of infectious diseases worldwide, it is crucial to understand the factors involved in these events. Among these factors, food resources and the microbiome appear central in the tripartite relationship composed of the host, the pathogens it transmits, and the environment. Thus, the objective of this thesis was to identify the links between biotic and abiotic environmental factors, the microbiome, and vector competence in mollusks and arthropods that vector zoonotic diseases. This research has enhanced our understanding of the bacterial communities within the microbiome of natural populations of Bulinus truncatus and Galba truncatula, and has studied the influence of environmental factors and host genetics on these communities. It has also evaluated the link between plant-based food resources and the vector competence of laboratory populations of Aedes albopictus. These studies provide new and relevant insights into how interactions between the environment, the microbiome, and host vector competence can influence the transmission dynamics of infectious diseases, offering perspectives for managing infectious diseases and identifying high-risk areas for emergence
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Luviano, Aparicio Nelia. "The DNA methylation of the snail Biomphalaria glabrata, role and impact on the generation of phenotypic plasticity A simple Dot Blot Assay for population scale screening of DNA methylation The methylome of Biomphalaria glabrata and other mollusks: enduring modification of epigenetic landscape and phenotypic traits by new DNA methylation inhibitors An approach to study the relative contributions of epigenetics and genetics to phenotypic plasticity in the mollusk Biomphalaria glabrata, vector of the human parasite Schistosoma mansoni Hit-and-run epigenetic editing in the invertebrate parasite intermediate host snail Biomphalaria glabrata". Thesis, Perpignan, 2021. http://www.theses.fr/2021PERP0004.
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La compréhension des mécanismes moléculaires qui permettent l'adaptation rapide des mollusques vecteurs de parasites à de nouveaux environnements est importante pour le contrôle des maladies. L'adaptation rapide est difficile à expliquer par la génétique mendélienne traditionnelle et il existe des preuves solides qui soutiennent que les mécanismes épigénétiques sont à l'origine des adaptations rapides chez plusieurs espèces. Je me suis focalisée sur une marque épigénétique appelée la méthylation de l’ADN, qui est modulée par l'environnement et joue un rôle dans la plasticité phénotypique chez de nombreuses espèces, principalement les plantes et les vertébrés. Néanmoins, le rôle de la méthylation de l'ADN dans la génération de variations phénotypiques chez les invertébrés a été très peu étudié. J'ai abordé la question du rôle de la méthylation de l'ADN dans la génération de la plasticité phénotypique et de son héritabilité chez l'escargot B. glabrata, l'hôte intermédiaire du parasite Schistosoma mansoni, l'agent pathogène de la schistosomiase, une maladie tropicale négligée. La méthylation de l'ADN chez B. glabrata est régulée par l'infection3du parasite S. mansoni et par le stress environnemental, de plus, il a été démontré que la méthylation de l'ADN affecte son expression génique, suggérant que la méthylation de l'ADN peut affecter la variation phénotypique et donc l'adaptation de l'escargot à de nouveaux environnements. Pour étudier le rôle de la méthylation de l'ADN dans la génération de la variation phénotypique, une manipulation expérimentale de la méthylation de l'ADN chez l'escargot était nécessaire. Par conséquent, deux approches ont été proposées dans cette thèse pour introduire des épimutations chez l'escargot B. glabrata: 1) Épi-mutagenèse aléatoire en utilisant des inhibiteurs chimiques des enzymes ADN methyltransferases (DNMT) et par ségrégation conséquente des épimutations dans des lignées d'autofécondation et 2) Par la méthylation des cytosines d'un locus ciblé avec un outil d'édition épigénétique qui consiste à l'utilisation d'une vecteur plasmidique codant pour l’ADN méthyltranférase (DNMT3) fusionnée avec l’enzyme dCas9 (Cas9 avec l’activité nucléase désactivé). Pour l’approche d’épimutagenèse aleatoire, un nouvel inhibiteur des enzymes DNMT a montré des effets d’inhibition de la méthylation dans deux générations consécutives, en montrant un effet épigénétique multigénérationnelle et sans montrer d’effet toxique ni dans la survie ni dans la fécondité de l’escargot B. glabrata. De plus l’inhibiteur Flv1 a montré être efficace dans deux autres espèces de mollusques, l’escargot d’eau douce Physa acuta et l’huître creuse Crassostrea gigas, ce qui suggère que cet inhibiteur représente un potentiel outil moléculaire pour moduler la méthylation de l’ADN chez d’autres mollusques. Dans le cas de l’approche ciblée, j’ai utilisé une méthode de transfection qui permet d’introduire deux vecteurs plasmidiques avec un promoteur viral SV40 de façon in vivo dans des embryons de l’escargot B. glabrata. La transfection a été effectuée au stade gastrula, ce qui a entrainé une incorporation mosaïque du vecteur dans les cellules transfectées. Toutefois, la méthode a permis de méthyler certains sites CpG du gène cibléThe understanding of the molecular mechanisms that allows the rapid adaptation of mollusks that are vector of parasites, to new environments is important for disease control. Rapid adaptation is difficult to explain by traditional Mendelian genetics and there is strong evidence supporting that epigenetic mechanisms, are behind rapid adaptations in other species. I studied one epigenetic mark called DNA methylation that has demonstrated to be environmentally modulated and to play a role in phenotypic plasticity in many species, principally plants and vertebrates. Nevertheless, the role of DNA methylation in generating phenotypic variation in invertebrates has been poorly studied. I addressed the question of the role of DNA methylation in the generation of phenotypic plasticity and its heritability in the snail Biomphalaria glabrata, the intermediate host of the parasite Schistosoma mansoni, the causal agent of schistosomiasis, a neglected tropical disease. DNA methylation in B. glabrata has been found to be modulated by the infection of the parasite S. mansoni and by environmental stress, furthermore, it was demonstrated that DNA methylation affects its gene expression, suggesting that DNA methylation can affect phenotypic variation and therefore the adaptation of the snail to new environments. To study the role of DNA methylation in the generation of phenotypic variation, experimental manipulation of the DNA methylation in the snail was necessary. Therefore, two approaches were proposed in this thesis to introduce epimutations in the snail B. glabrata: 1) Random epi-mutagenesis using chemical DNA methyltransferase (DNMT) inhibitors and by consequent segregation of epimutations in self-fertilization lines and 2) Methylate the cytosines of a targeted locus with a targeted epigenome editing tool consisting in the use of the DNA methyltransferase (DNMT3) construct fused to the nuclease-inactivated dCas9. For the random epi-mutagenesis approach, a novel DNMT inhibitor has shown methylation inhibiting effects in two subsequent generations, showing a2multigenerational epigenetic effect and without showing toxic effects in either survival nor fecundity of the snail B. glabrata. In addition, the inhibitor Flv1 has been shown to be effective in other two mollusk species, the freshwater snail Physa acuta and the pacific oyster Crassostrea gigas, which suggests that this inhibitor represents a molecular tool to modulate the methylation of DNA in other mollusks. In the case of the targeted epimutagenesis approach, I used a transfection method that allows introducing two plasmid vectors with an SV40 viral promoter in vivo in embryos of the snail B. glabrata. The transfection was performed at the gastrula stage, which resulted in mosaic incorporation of the vector into the transfected cells. However, the method was able to methylate some CpG sites of the targeted gene
Capítulos de livros sobre o assunto "Vector / intermediate host"
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Saijuntha, Weerachai, Ross H. Andrews, Paiboon Sithithaworn e Trevor N. Petney. "Biodiversity of Human Trematodes and Their Intermediate Hosts in Southeast Asia". In Biodiversity of Southeast Asian Parasites and Vectors causing Human Disease, 63–95. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-71161-0_4.
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Anderson, Roy M., e Robert M. May. "Indirectly transmitted microparasites". In Infectious Diseases of Humans, 374–430. Oxford University PressOxford, 1991. http://dx.doi.org/10.1093/oso/9780198545996.003.0014.
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Abstract Many important microparasitic infections of humans are indirectly transmitted from person to person by biting arthropods such as mosquitoes. A list of the major infections is presented in Table 14.1. An idea of their global significance is provided by the observation that the protozoan malarial infections on the continent of Africa alone are estimated to cause in excess of one million child deaths annually (Walsh and Warren 1979). The term ‘vector transmitted’ is often used to describe these infections but it should be noted that the vector is invariably a true intermediate host, in the sense that the parasite undergoes a phase of obligatory development (and often reproduction) within the arthropod.
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Kumar, Ankur, Priyanka Singh, Ganesh Kumar Verma, Avinash Bairwa, Priyanka Naithani, Jitender Gairolla, Ashish Kothari, Kriti Mohan e Balram Ji Omar. "Pondering Plasmodium: Revealing the Parasites Driving Human Malaria and Their Core Biology in Context of Antimalarial Medications". In Plasmodium Species - Life Cycle, Drug Resistance and Autophagy [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.115132.
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Malaria is one of the most severe infectious diseases, imposing significant clinical and financial burdens, particularly in underdeveloped regions, and hindering socioeconomic development. The disease is caused by unicellular protozoan parasites of the genus Plasmodium, which infect not only humans but also various animals, including birds, mammals, and reptiles. Among over 200 recognized Plasmodium species, five—P. falciparum, P. vivax, P. malariae, P. ovale, and P. knowlesi—pose serious risks to human health. The first four are specific to humans, while P. knowlesi, primarily found in macaque monkeys, is responsible for zoonotic malaria in Southeast Asia. Malaria transmission relies on an intermediate insect vector, typically Anopheles mosquitoes, which act as both carriers and final hosts, facilitating the sexual reproduction of the parasite. This dependence on anopheline mosquitoes underscores the complex ecological dynamics influencing malaria epidemiology. Plasmodium species exhibit significant genetic plasticity, enabling rapid adaptation to external pressures such as changes in host specificity and the evolution of treatment resistance. This chapter explores the biology of human-infecting Plasmodium species and the significant threats they pose to humanity, highlighting their complex interactions with hosts and vectors.
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Tonev, Anton. "Perspective Chapter: The Parasitic Component". In Bacterial, Viral and Fungal Coinfections [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.114391.
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There is no tissue or organ in the body of plants, animals and man in which some parasitic species have not adapted to live. Blood, brain, liver and striated and cardiac muscles, which we are used to in classical microbiology to perceive, a priori, as sterile organs, are in fact often the home of some parasitic species. This ecological idyll often terrifies clinicians and owners, especially when it comes to parasitic species utilizing humans as final, intermediate or potential hosts. The parasites are well adapted to pass the barriers that the body puts in front of other microorganisms, thus creating a bridgehead used by other parasites, viruses, bacteria or fungi. In itself, the presence of hideous lodgers on and in the body does not necessarily cause any harm to the host, and the drive to destroy the “monsters within us” must be carefully weighed. The discovery of organisms’ microbiomes complex systems has changed our understanding of pathogens, and we need to develop a more complex understanding of the “pathobiome,” in which the pathogen is integrated into its abiotic and biotic environment and disease. This especially concerns vector-borne diseases. Today, we already talk not only about mosquito-, fly-, sand fly-, lice-, flea-, tick-, mite-, gastropod- and bug- but also about plant- and fungi-, warm-blooded animal- and even human-borne diseases, each admittedly carries its own pathobiome.
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Tinsley, F. C. "Parasites of Xenopus". In The Biology of Xenopus, 233–60. Oxford University PressOxford, 1996. http://dx.doi.org/10.1093/oso/9780198549741.003.0013.
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Abstract The Xenopus species carry a richer assemblage of parasites than most other anurans, with over 25 genera from seven invertebrate groups. This spectrum reflects a dual origin: some of the parasites are characteristic of anurans and represent ‘heirlooms’ from a common ancestry of parasites which have evolved with the anuran lineages. In addition, a component of the fauna is related to parasites which typically infect fishes: these represent ecological acquisitions and reflect the overlap, in terms of diet, habitats etc., between Xenopus and fish. For both these subsets of parasites, the representatives infecting Xenopus are highly distinctive, with life-history and other specializations which are often unique within the respective parasite groups. From a systematic point of view, they are best interpreted as having had a very distant origin from their nearest relatives and having now diverged to the point where almost all forms infecting Xenopus are placed in their own genera, families or higher taxonomic categories, strictly specific to Xenopus. Some of the parasites exploit Xenopus as an intermediate host and await passage to final hosts which are predators of Xenopus (and usually also of fish). These parasites may be pathogenic, infecting the heart, body musculature, eyes and lateral line system: by interfering with normal function, infection increases the risks of predation and thus facilitates completion of the parasite’s life cycle. Other parasites employ Xenopus as a final host (in which their sexual reproduction occurs), and invade by a variety of routes (with the diet, by vector transfer, or by direct penetration of an active infective stage). For most of these parasites, pathogenic effects are difficult to detect and infection levels tend to occur below the point at which damage may be serious. The skin-infecting nematode, Pseudocapillaroides xenopodis, is exceptional in its pathogenicity, being responsible for lethal epidemics amongst laboratory-maintained X. laevis.
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Anderson, Roy M., e Robert M. May. "Biology of host-microparasite associations". In Infectious Diseases of Humans, 27–65. Oxford University PressOxford, 1991. http://dx.doi.org/10.1093/oso/9780198545996.003.0003.
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Abstract Our operational definition of a microparasite encompasses a wide variety of different organisms ranging from simple viruses to ontogenetically complex organisms such as the malarial parasites. Their life cycles may be simple with transmission from person to person being direct, through contact with infective stages that are free-living in the environment, or through intimate contact between hosts such that no free-living phase occurs (e.g. the sexually transmitted infections), or through vectors or intermediate hosts within which parasite development or reproduction may or may not occur. Development during the life cycle may again be simple, as in the case of viral replication within a host cell and transmission between cells, or highly complex as in the alternate phases of asexual and sexual reproduction in the life cycles of the malarial or trypanosome protozoan parasites. We do not discuss here the recondite details that make each parasite life cycle distinct since this approach is well covered by other texts (see Fenner and White 1975; Cox 1982). Instead we focus on two areas: the first concerns immune responses to microparasitic infection and their consequences for population growth of a parasite within an individual host; and the second concerns the epidemiological data that are available (or can in practice be acquired) both to estimate model parameters and to test theoretical predictions.
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Nizetic, Dean, e Hans Lehrach. "Chromosome-specific gridded cosmid libraries: construction, handling, and use in parallel and integrated mapping". In DNA Cloning 3, 49–80. Oxford University PressOxford, 1995. http://dx.doi.org/10.1093/oso/9780199634835.003.0002.
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Abstract The analysis of the information in human genomic DNA is based on the cloning and molecular characterization of the genes together with the genetic analysis of the phenotypes a-;sociated with the genetic loci under study. Libraries of cloned genomic DNA serve as essential intermediates to relate the information from the genetic analysis of phenotypic variation to the molecular analysis of the genes (I). Such libraries, can be either constructed in a yeast or bacterial vector-host system. The yeast system. using yeast artificial chromosomes (YACs) (2) as vectors, is well suited for rapid coverage of long genomic regions and entire chromosomes (3) (see also Chapter 4). This offers easier integration of the data with the genetic and physical maps of the genomic DNA, for example in the comparison of the maps of cloned DNA to long-range restriction maps of genomic DNA constructed using restriction endonucleases that cut at infrequent intervals. The yeast system is however not the best choice for the application of methods to identify transcribed regions (genes), to analyse the transcription unit and exon-intron organization, and to obtain the sequence of the genes. The longer the YAC clones arc, the more frequently they suffer from deletions, rearrangements, co-cloning, and chimerism, which makes the establishment of a highresolution map difficult. Moreover, irrespective of the YAC length, the isolation of pure YAC DNA from the genomic DNA of the host is difficult to achieve in most cases (sec Chapter 4 for a discussion of these problems). The bacterial (E. coli)-based vector systems (phage, cosmid, Pl, F-) (4-6) are much more suitable for the characterization of transcribed sequences (7-10), to study the molecular organization of the genes (11), and to provide material for DNA sequencing. The isolation of the cloned DNA in a pure state, free from the DNA of the host, is much more straightforward. Cosmid libraries are probably the simplest to use. They can be constructed with very high efficiency, allowing libraries to be made from limited amounts of DNA, and have been in use for longer than the Pl, PAC, and other new bacterial vector systems.
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Choudhari, Ranjana Hanumant. "Multidimensional Impact of Climate Change on Human Reproduction and Fertility". In Research Anthology on Environmental and Societal Impacts of Climate Change, 1672–709. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-3686-8.ch083.
Texto completo da fonteResumo:
Research has identified a multidimensional, interactive relationship between climate change variables and an adverse (mostly) impact on the mammalian reproductive systems, reproductive organs, and fertility in animals, but direct evidence establishing the impact of climate change on reproductive health and fertility in humans is limited. Climate change has established direct or indirect linkages with re-emergence, geospatial redistribution of pathogens of likely reproductive health significance in humans. Similarly, alterations in growth, mortality rate, reproduction, and spatiotemporal distribution of vectors (e.g., zika virus – Aedes aegypti) and intermediate hosts (e.g., Schistosomiasis – snail) of certain infectious diseases of reproductive health importance are influenced by climate change variables like temperature, precipitation, and humidity. The exposure channels or effect pathways, through which the regional and global climate change can directly or indirectly influence the human reproductive ability, health, fertility, progeny, and thus, ultimately, demography can broadly be classified as physical variables, chemical hazards, biological agents, factors related to psycho-socio-behavior, and economy. The chapter is an overall account of how each of these factors, as an inherent component of climate change has the potential to cause a variable degree of impact on human reproduction from a medical point of view. As human reproductive systems are highly vulnerable to diseases and other post-catastrophic effects of extreme climate change events, so it is high time to understand the adversity and resort to proper and sustainable control measures for a healthy reproductive life of future generations.
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Choudhari, Ranjana Hanumant. "Multidimensional Impact of Climate Change on Human Reproduction and Fertility". In Climate Change and Its Impact on Fertility, 278–315. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4480-8.ch014.
Texto completo da fonteResumo:
Research has identified a multidimensional, interactive relationship between climate change variables and an adverse (mostly) impact on the mammalian reproductive systems, reproductive organs, and fertility in animals, but direct evidence establishing the impact of climate change on reproductive health and fertility in humans is limited. Climate change has established direct or indirect linkages with re-emergence, geospatial redistribution of pathogens of likely reproductive health significance in humans. Similarly, alterations in growth, mortality rate, reproduction, and spatiotemporal distribution of vectors (e.g., zika virus – Aedes aegypti) and intermediate hosts (e.g., Schistosomiasis – snail) of certain infectious diseases of reproductive health importance are influenced by climate change variables like temperature, precipitation, and humidity. The exposure channels or effect pathways, through which the regional and global climate change can directly or indirectly influence the human reproductive ability, health, fertility, progeny, and thus, ultimately, demography can broadly be classified as physical variables, chemical hazards, biological agents, factors related to psycho-socio-behavior, and economy. The chapter is an overall account of how each of these factors, as an inherent component of climate change has the potential to cause a variable degree of impact on human reproduction from a medical point of view. As human reproductive systems are highly vulnerable to diseases and other post-catastrophic effects of extreme climate change events, so it is high time to understand the adversity and resort to proper and sustainable control measures for a healthy reproductive life of future generations.
10
Choudhari, Ranjana Hanumant. "Multidimensional Impact of Climate Change on Human Reproduction and Fertility". In Climate Change and Its Impact on Fertility, 278–315. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4480-8.ch014.
Texto completo da fonteResumo:
Research has identified a multidimensional, interactive relationship between climate change variables and an adverse (mostly) impact on the mammalian reproductive systems, reproductive organs, and fertility in animals, but direct evidence establishing the impact of climate change on reproductive health and fertility in humans is limited. Climate change has established direct or indirect linkages with re-emergence, geospatial redistribution of pathogens of likely reproductive health significance in humans. Similarly, alterations in growth, mortality rate, reproduction, and spatiotemporal distribution of vectors (e.g., zika virus – Aedes aegypti) and intermediate hosts (e.g., Schistosomiasis – snail) of certain infectious diseases of reproductive health importance are influenced by climate change variables like temperature, precipitation, and humidity. The exposure channels or effect pathways, through which the regional and global climate change can directly or indirectly influence the human reproductive ability, health, fertility, progeny, and thus, ultimately, demography can broadly be classified as physical variables, chemical hazards, biological agents, factors related to psycho-socio-behavior, and economy. The chapter is an overall account of how each of these factors, as an inherent component of climate change has the potential to cause a variable degree of impact on human reproduction from a medical point of view. As human reproductive systems are highly vulnerable to diseases and other post-catastrophic effects of extreme climate change events, so it is high time to understand the adversity and resort to proper and sustainable control measures for a healthy reproductive life of future generations.
Trabalhos de conferências sobre o assunto "Vector / intermediate host"
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Fedorova, V. S., V. A. Burlak e G. N. Artemov. "SPECIES COMPOSITION OF NEMATODES ON MALARIA MOSQUITOES OF THE TOMSK REGION". In V International Scientific Conference CONCEPTUAL AND APPLIED ASPECTS OF INVERTEBRATE SCIENTIFIC RESEARCH AND BIOLOGICAL EDUCATION. Tomsk State University Press, 2020. http://dx.doi.org/10.17223/978-5-94621-931-0-2020-81.
Texto completo da fonteResumo:
The species composition of nematodes and their vectors were analyzed in the Tomsk region. It has been shown that all three species of malaria mosquitoes, Anopheles messeae s.s., An. daciae and An. beklemishevi, can transmit Dirofilaria repens in 89% of confirmed cases. The species-specific infection of the intermediate host with dirofilarias depends on the geographical location.
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Lisovskaya, T. M., e N. S. Malysheva. "IMPACT OF CLIMATIC CHANGES ON THE SPREAD OF DIROFILARIASIS IN THE KURSK REGION". In THEORY AND PRACTICE OF PARASITIC DISEASE CONTROL. VNIIP – FSC VIEV, 2024. http://dx.doi.org/10.31016/978-5-6050437-8-2.2024.25.236-240.
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The article considers an impact of climatic changes and an average temperature increase of the Earth's surface on dirofilariasis spread in the Kursk Region. Climatic changes are irreversible and an urgent problem for the modern world. In this regard, vector-borne diseases specific for a certain climatic zone are increasingly found in areas where the manifestation of such diseases is not typical. Dirofilariasis is a transmissible infection caused by nematodes of the genus Dirofilaria. Intermediate hosts of nematodes Dirofilaria repens and D. immitis are Culicidae mosquitoes. Due to an increase in the average annual temperature, the spread of this helminthiasis vectors increases, which contributes to a more active disease circulation and the infection of a larger number of obligate definitive hosts (dogs, less often cats) and people. There also occurs a human infection caused by "basement" mosquitoes in the presence of infected stray animals in urban conditions throughout the year. According to the State Report materials on sanitary and epidemiological welfare of the population in the Kursk Region, human dirofilariasis cases have been observed over the past decades; previously this parasitosis was mainly found in more southern regions of the Russian Federation.
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Movsesyan, S. O., R. A. Petrosyan, M. A. Nikogosyan, R. E. Barsegyan, N. B. Terenina, M. V. Voronin e M. V. Vardanyan. "BIODIVERSITY OF THE PARASITE FAUNA IN THE NORTHERN REGIONS OF ARMENIA AND THE LAKE SEVAN BASIN". In THEORY AND PRACTICE OF PARASITIC DISEASE CONTROL. All-Russian Scientific Research Institute for Fundamental and Applied Parasitology of Animals and Plant – a branch of the Federal State Budget Scientific Institution “Federal Scientific Centre VIEV”, 2023. http://dx.doi.org/10.31016/978-5-6048555-6-0.2023.24.306-311.
Texto completo da fonteResumo:
The variety of parasite species, infection of domesticated animals (including cattle,
sheep, goats, rabbits, poultry, dogs and pigs), natural infection of biohelminths'
intermediate hosts (including terrestrial and freshwater mollusks, soil oribatid mites)
with helminth larvae, and the species composition of tick vectors of blood protozoan
diseases have been studied. The studies found the infection of the above animals with
the following helminth species: 4 trematode species Fasciola hepatica, F. gigantica,
Dicrocoelium lanceatum, Paramphistomum sp., 13 nematode species Ascaris suum, A.
galli, Syngamus trachea, Capillaria caudinflata, Trichuris ovis, Tr. suis, Metastrongylus
elongatus, Chabertia sp., Haemonchus sp., Protostrongylus spp., Muellerius capillaris,
Dictyocaulus filaria, Cystocaulus nigrescens, 2 cestode species Moniezia expansa, M.
benedeni; 9 eimeria species Eimeria arloingi, E. intricata, E. stidae, E. magna, E.
perforans, E. tenella, E. acervulina, and E. exigua; 3 Haemosporidia species Babesia
bigeminum, B. ovis, and B. canis; and 1 Leishmania species Leishmania tropica.
There were also detected 17 species of ticks, vectors of blood protozoan diseases of
animals, and intermediate hosts of moniezia were isolated. Two species of terrestrial
and 3 species of freshwater mollusks being as intermediate hosts of helminths were
recorded.
Relatórios de organizações sobre o assunto "Vector / intermediate host"
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Tzfira, Tzvi, Michael Elbaum e Sharon Wolf. DNA transfer by Agrobacterium: a cooperative interaction of ssDNA, virulence proteins, and plant host factors. United States Department of Agriculture, dezembro de 2005. http://dx.doi.org/10.32747/2005.7695881.bard.
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Agrobacteriumtumefaciensmediates genetic transformation of plants. The possibility of exchanging the natural genes for other DNA has led to Agrobacterium’s emergence as the primary vector for genetic modification of plants. The similarity among eukaryotic mechanisms of nuclear import also suggests use of its active elements as media for non-viral genetic therapy in animals. These considerations motivate the present study of the process that carries DNA of bacterial origin into the host nucleus. The infective pathway of Agrobacterium involves excision of a single-stranded DNA molecule (T-strand) from the bacterial tumor-inducing plasmid. This transferred DNA (T-DNA) travels to the host cell cytoplasm along with two virulence proteins, VirD2 and VirE2, through a specific bacteriumplant channel(s). Little is known about the precise structure and composition of the resulting complex within the host cell and even less is known about the mechanism of its nuclear import and integration into the host cell genome. In the present proposal we combined the expertise of the US and Israeli labs and revealed many of the biophysical and biological properties of the genetic transformation process, thus enhancing our understanding of the processes leading to nuclear import and integration of the Agrobacterium T-DNA. Specifically, we sought to: I. Elucidate the interaction of the T-strand with its chaperones. II. Analyzing the three-dimensional structure of the T-complex and its chaperones in vitro. III. Analyze kinetics of T-complex formation and T-complex nuclear import. During the past three years we accomplished our goals and made the following major discoveries: (1) Resolved the VirE2-ssDNA three-dimensional structure. (2) Characterized VirE2-ssDNA assembly and aggregation, along with regulation by VirE1. (3) Studied VirE2-ssDNA nuclear import by electron tomography. (4) Showed that T-DNA integrates via double-stranded (ds) intermediates. (5) Identified that Arabidopsis Ku80 interacts with dsT-DNA intermediates and is essential for T-DNA integration. (6) Found a role of targeted proteolysis in T-DNA uncoating. Our research provide significant physical, molecular, and structural insights into the Tcomplex structure and composition, the effect of host receptors on its nuclear import, the mechanism of T-DNA nuclear import, proteolysis and integration in host cells. Understanding the mechanical and molecular basis for T-DNA nuclear import and integration is an essential key for the development of new strategies for genetic transformation of recalcitrant plant species. Thus, the knowledge gained in this study can potentially be applied to enhance the transformation process by interfering with key steps of the transformation process (i.e. nuclear import, proteolysis and integration). Finally, in addition to the study of Agrobacterium-host interaction, our research also revealed some fundamental insights into basic cellular mechanisms of nuclear import, targeted proteolysis, protein-DNA interactions and DNA repair.