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1.
PLoS One ; 15(12): e0244760, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33378394

RESUMO

Placobdelloides siamensis is a glossiphoniid leech with a short life cycle. In a laboratory setting, ten mature P. siamensis left their host (a turtle) after feeding for approximately three days and initiated copulation. The adults spent 3-4 days gestating before depositing eggs (272.8±62.9 eggs/clutch; range: 186-359 eggs/clutch). The eggs then changed from a creamy white to a creamy brownish color before hatching. Hatching occurred after incubation on the parent's ventral surface for 5-7 days. The transparent brood, with a single pair of red eyes, spent a couple of weeks under the venters of their parents. After this period, they left their parents and grew to maturity in 10-15 days; leeches were considered mature when their color was similar to that of their parents and they performed their first copulation. In addition, the mature leeches survived for 163 days on one feeding.


Assuntos
Sanguessugas/fisiologia , Estágios do Ciclo de Vida/fisiologia , Animais , Tartarugas/parasitologia
2.
Parasitol Res ; 119(10): 3401-3413, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32780185

RESUMO

In wildlife, endoparasite burden can be affected by host life history stage, environmental conditions, host abundance, and parasite co-infections. We tested the effects of these factors on gastrointestinal parasite infection in plains zebras (Equus quagga) in the Serengeti ecosystem, Tanzania, using fecal egg counts of two nematode families (Strongylidae and Ascarididae) and the presence/absence of cestode (Anoplocephalidae) eggs. We predicted higher egg counts of Strongylidae and Ascarididae, and increased likelihood of Anoplocephalidae infection in individuals (1) during energetically costly life history stages when resource allocation to immune processes may decrease and in young zebras after weaning because of increased uptake of infective stages with forage, (2) when climatic conditions facilitate survival of infective stages, (3) when large zebra aggregations increase forage contamination with infective stages, and (4) in individuals co-infected with more than one parasite group as this may indicate reduced immune competence. Strongylidae egg counts were higher, and the occurrence of Anoplocephalidae eggs was more likely in bachelors than in band stallions, whereas Ascarididae egg counts were higher in band stallions. Strongylidae and Ascarididae egg counts were not increased in lactating females. Strongylidae egg counts were higher in subadults than in foals. Regardless of sex and age, Ascarididae infections were more likely under wet conditions. Co-infections did not affect Strongylidae egg counts. Ascarididae egg counts in adult females were higher when individuals were co-infected with Anoplocephalidae. We present evidence that parasite burdens in plains zebras are affected by life history stage, environmental conditions, and co-infection.


Assuntos
Equidae/crescimento & desenvolvimento , Equidae/parasitologia , Enteropatias Parasitárias/veterinária , Estágios do Ciclo de Vida/fisiologia , Contagem de Ovos de Parasitas/veterinária , Animais , Animais Selvagens , Clima , Feminino , Helmintos/classificação , Helmintos/crescimento & desenvolvimento , Helmintos/isolamento & purificação , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Masculino , Parques Recreativos , Tanzânia/epidemiologia
3.
Trends Parasitol ; 36(9): 785-795, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32713762

RESUMO

Leishmania parasites have the capacity to rapidly adapt to changing environments in their digenetic life cycle which alternates between a vertebrate and an invertebrate host. Emergence of resistance following drug exposure can evoke phenotypic alterations that affect several aspects of parasite fitness in both hosts. Current studies of the impact of resistance are mostly limited to interactions with the mammalian host and characterization of in vitro parasite growth and differentiation. Development in the vector and transmission capacity have been largely ignored. This review reflects on the impact of drug resistance on its spreading potential with specific focus on the use of the sand fly infection model to evaluate parasite development in the vector and the ensuing transmission potential of drug-resistant phenotypes.


Assuntos
Resistência a Medicamentos , Insetos Vetores/parasitologia , Leishmaniose/transmissão , Psychodidae/parasitologia , Animais , Antiparasitários/farmacologia , Humanos , Leishmania/efeitos dos fármacos , Leishmania/crescimento & desenvolvimento , Leishmaniose/parasitologia , Estágios do Ciclo de Vida/fisiologia
4.
PLoS One ; 15(7): e0234868, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32667920

RESUMO

The tiger shark (Galeocerdo cuvier) is globally distributed with established coastal and open-ocean movement patterns in many portions of its range. While all life stages of tiger sharks are known to occur in the Gulf of Mexico (GoM), variability in habitat use and movement patterns over ontogeny have never been quantified in this large marine ecosystem. To address this data gap we fitted 56 tiger sharks with Smart Position and Temperature transmitting tags between 2010 and 2018 and examined seasonal and spatial distribution patterns across the GoM. Additionally, we analyzed overlap of core habitats (i.e., 50% kernel density estimates) among individuals relative to large benthic features (oil and gas platforms, natural banks, bathymetric breaks). Our analyses revealed significant ontogenetic and seasonal differences in distribution patterns as well as across-shelf (i.e., regional) and sex-linked variability in movement rates. Presumably sub-adult and adult sharks achieved significantly higher movement rates and used off-shelf deeper habitats at greater proportions than juvenile sharks, particularly during the fall and winter seasons. Further, female maximum rate of movement was higher than males when accounting for size. Additionally, we found evidence of core regions encompassing the National Oceanographic and Atmospheric Administration designated Habitat Areas of Particular Concern (i.e., shelf-edge banks) during cooler months, particularly by females, as well as 2,504 oil and gas platforms. These data provide a baseline for future assessments of environmental impacts, such as climate variability or oil spills, on tiger shark movements and distribution in the region. Future research may benefit from combining alternative tracking tools, such as acoustic telemetry and genetic approaches, which can facilitate long-term assessment of the species' movement dynamics and better elucidate the ecological significance of the core habitats identified here.


Assuntos
Migração Animal/fisiologia , Demografia/métodos , Tubarões/crescimento & desenvolvimento , Animais , Ecossistema , Feminino , Golfo do México , Estágios do Ciclo de Vida/fisiologia , Masculino , Tubarões/metabolismo , Tubarões/fisiologia
5.
Rev Saude Publica ; 54: 48, 2020.
Artigo em Inglês, Português | MEDLINE | ID: mdl-32491093

RESUMO

OBJECTIVE To identify the Brazilian cohorts that started either in the prenatal period or at birth, to describe their characteristics and the explored variables, and to map the cohorts with potential for studies on early determinants on health and the risk of falling ill on later stages of the life cycle. METHODS A scoping review was carried out. The articles were searched in the electronic databases PubMed and Virtual Health Library (VHL). The descriptors used were [((("Child" OR "Child, Preschool" OR "Infant" OR "Infant, Newborn") AND (Cohort Studies" OR "Longitudinal Studies")) AND "Brazil")]. The inclusion criteria were Brazilian cohorts that started the baseline in the prenatal period or at birth and with at least two follow-ups with the participants. In order to meet the concept of LCE, we excluded those cohorts whose follow-ups were restricted to the first year of life, as well as those that did not address biological, behavioral and psychosocial aspects, and cohorts with data collection of a single stage of the life cycle. RESULTS The search step identified 5,010 articles. Eighteen cohorts were selected for descriptive synthesis. The median number of baseline participants was 2,000 individuals and the median age at the last follow-up was 9 years. Sample loss at the last follow-up ranged from 9.2 to 87.5%. Most cohorts monitored two phases of the life cycle (the perinatal period and childhood). The Southern region had the highest number of cohorts. The main variables collected were sociodemographic and environmental aspects of the family, morbidity aspects, nutritional practices and lifestyle. CONCLUSIONS We recommend the continuity of these cohorts, the approach to different social contexts and the performance of follow-ups with participants in different phases of the life cycle for the strengthening and expansion of life course epidemiology analyses in Brazil.


Assuntos
Desenvolvimento Infantil/fisiologia , Estudos de Coortes , Estágios do Ciclo de Vida/fisiologia , Fatores Etários , Brasil , Criança , Pré-Escolar , Projetos de Pesquisa Epidemiológica , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Gravidez
6.
Parasitol Res ; 119(8): 2421-2430, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32548738

RESUMO

The present study aimed to evaluate biological parameters of Rhipicephalus microplus in the non-parasitic phase in both field and laboratory conditions. It also aimed to assess correlations between duration (in days) of these parameters and climatic variables (humidity, rainfall, and soil temperature) and to estimate the annual number of generations of R. microplus in a tropical region. The non-parasitic phase of R. microplus in field and laboratory conditions was evaluated throughout the course of two years. A pasture was infested with engorged female of R. microplus, and biological parameters, including female pre-oviposition, female oviposition, egg mass incubation, larval pre-hatching phase, larval maturation, and larval longevity, were evaluated concomitantly with the collection of data on climatic conditions. The same parameters were also evaluated in a climatized chamber in the laboratory. The total duration of the non-parasitic phase in the field was longer in the dry season (1st and 4th life-cycle repetitions) than in the rainy season (2nd, 3rd, and 5th repetitions). Tick biological parameters for the non-parasitic phase in the laboratory were similar to those obtained in the field during the rainy season. The evaluated biological parameters were influenced mainly by environmental and ground-level temperatures, which modified egg mass incubation, larval pre-hatching, and larval longevity periods and, consequently, the total duration of the non-parasitic phase of the tick. The annual number of generations for the tick was estimated at five per year, which is alarming because it represents an increase, and so new studies into strategic control are needed.


Assuntos
Clima , Estágios do Ciclo de Vida/fisiologia , Animais , Bovinos , Feminino , Larva , Longevidade , Oviposição , Rhipicephalus/fisiologia , Fatores de Tempo
8.
Trends Parasitol ; 36(6): 512-519, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32360314

RESUMO

Trager and Jensen established a method for culturing Plasmodium falciparum, a breakthrough for malaria research worldwide. Since then, multiple attempts to establish Plasmodium vivax in continuous culture have failed. Unlike P. falciparum, which can invade all aged erythrocytes, P. vivax is restricted to reticulocytes. Thus, a constant supply of reticulocytes is considered critical for continuous P. vivax growth in vitro. A critical question remains why P. vivax selectively invades reticulocytes? What do reticulocytes offer to P. vivax that is not present in mature erythrocytes? One possibility is protection from oxidative stress by glucose-6-phosphate dehydrogenase (G6PD). Here, we also suggest supplements to the media and procedures that may reduce oxidative stress and, as a result, establish a system for the continuous culture of P. vivax.


Assuntos
Técnicas de Cultura/normas , Estágios do Ciclo de Vida/fisiologia , Plasmodium vivax/crescimento & desenvolvimento , Reticulócitos/parasitologia , Técnicas de Cultura/tendências , Eritrócitos/enzimologia , Eritrócitos/parasitologia , Interações Hospedeiro-Parasita , Humanos , Estresse Oxidativo , Reticulócitos/enzimologia
9.
Eur J Protistol ; 74: 125690, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32305704

RESUMO

Marine parasites of the genus Parvilucifera have been described as endoparasitoids of dinoflagellates. Recently, the species Parvilucifera corolla was described, but its host range was not examined. Here, the host selectivity of P. corolla was screened, including 110 strains of dinoflagellates (24 genera) and other microalgal groups as potential hosts. Infections and the full life cycle of the parasitoid were observed in 73 strains (16 genera) of dinoflagellates. Parvilucifera corolla did not infect most chlorophytes, cryptophytes, chrysophytes, diatoms, haptophytes and raphidophytes but one strain of Pyramimonas (chlorophyte) was infected, although without viable sporangia. In Symbiodinium natans, a transition to the coccoid stage was induced above a certain parasite:host ratio. These results confirm P. corolla as a generalist parasitoid of dinoflagellates, with important differences in host range regarding other species of the genus.


Assuntos
Alveolados/fisiologia , Dinoflagelados/parasitologia , Especificidade de Hospedeiro , Organismos Aquáticos/parasitologia , Organismos Aquáticos/fisiologia , Estágios do Ciclo de Vida/fisiologia
10.
Sci Rep ; 10(1): 6637, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313143

RESUMO

Rhynocoris longifrons (Hemiptera: Reduviidae) is a generalist predator of many cotton insect pests. The hiding behaviour of this predator, which is one of the key factors of predation success, was investigated under screen house conditions. Moreover, we evaluated its biocontrol potential against Aphis gossypii (Hemiptera: Aphididae), Dysdercus cingulatus (Hemiptera: Pyrrhocoridae), Phenacoccus solenopsis (Hemiptera: Pseudococcidae), and Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) under screen house and field conditions. Results showed that R. longifrons life stages preferred to hide under small pebbles in the screen house tests. All the R. longifrons life stages showed a biocontrol potential against the four insect pests under screen house conditions. However, their biocontrol potential had not varied in relation to day and night hours. Augmentative releases of R. longifrons were carried out for two seasons such as South-west monsoon, 2011 and post-monsoon, 2012. The augmentative release of R. longifrons reduced significantly insect pests on cotton. In fact, the release of this predator in cotton fields was capable to reduce the population of H. armigera (50%), P. solenopsis (28%), D. cingulatus (18.8%), and A. gossypii (11.8%) during the rain fed condition (south-west monsoon season). During irrigated condition (post-monsoon season), populations of D. cingulatus were reduced by 26%, than P. solenopsis (20.6%), and A. gossypii (16.8%). Except ants, no negative impact was reported on other natural enemies present in the cotton field. Significantly higher crop yield and cost benefit ratio was observed in the predator release plots indicating that R. longifrons can be used in an integrated pest management program for multiple cotton pests.


Assuntos
Afídeos/fisiologia , Hemípteros/fisiologia , Lepidópteros/fisiologia , Estágios do Ciclo de Vida/fisiologia , Controle Biológico de Vetores/métodos , Comportamento Predatório/fisiologia , Reduviidae/fisiologia , Animais , Feminino , Gossypium/parasitologia , Índia , Masculino , Fotoperíodo , Estações do Ano
11.
PLoS One ; 15(4): e0227726, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32330137

RESUMO

Spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is an invasive economic pest of soft-skinned and stone fruit across the globe. Our study establishes both a predictive generalized linear mixed model (GLMM), and a generalized additive mixed model (GAMM) of the dynamic seasonal phenology of D. suzukii based on four years of adult monitoring trap data in Wisconsin tart cherry orchards collected throughout the growing season. The models incorporate year, field site, relative humidity, and degree days (DD); and relate these factors to trap catch. The GLMM estimated a coefficient of 2.21 for DD/1000, meaning for every increment of 1000 DD, trap catch increases by roughly 9 flies. The GAMM generated a curve based on a cubic regression smoothing function of DD which approximates critical DD points of first adult D. suzukii detection at 1276 DD, above average field populations beginning at 2019 DD, and peak activity at 3180 DD. By incorporating four years of comprehensive seasonal phenology data from the same locations, we introduce robust models capable of using DD to forecast changing adult D. suzukii populations in the field leading to the application of more timely and effective management strategies.


Assuntos
Drosophila/fisiologia , Frutas/parasitologia , Modelos Biológicos , Prunus avium/parasitologia , Estações do Ano , Animais , Monitorização de Parâmetros Ecológicos/estatística & dados numéricos , Previsões/métodos , Jardins/estatística & dados numéricos , Umidade , Controle de Insetos , Espécies Introduzidas/estatística & dados numéricos , Estágios do Ciclo de Vida/fisiologia , Modelos Lineares , Temperatura , Wisconsin
12.
Trends Parasitol ; 36(5): 407-408, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32298626

RESUMO

The progression to schizont formation of individual activated hypnozoites has been observed in vitro for the first time by Voorberg-van der Wel et al. Green-fluorescent protein-positive hypnozoites turned red-fluorescent (mCherry) upon activation. Thus, we now have empirical parasitological proof that supports the 40-year-old hypnozoite theory of relapse in malaria.


Assuntos
Estágios do Ciclo de Vida/fisiologia , Malária/parasitologia , Plasmodium/crescimento & desenvolvimento , Esquizontes/fisiologia , Animais , Células Cultivadas , Hepatócitos/parasitologia , Humanos
14.
PLoS One ; 15(4): e0227496, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32267864

RESUMO

Atlantic salmon migrate to sea following completion of a developmental process known as smolting, which establishes a seawater (SW) tolerant phenotype. Smolting is stimulated by exposure to long photoperiod or continuous light (LL) following a period of exposure to short photoperiod (SP), and this leads to major changes in gill ion exchange and osmoregulatory function. Here, we performed an RNAseq experiment to discover novel genes involved in photoperiod-dependent remodeling of the gill. This revealed a novel cohort of genes whose expression rises dramatically in fish transferred to LL following SP exposure, but not in control fish maintained continuously on LL or on SP. A follow-up experiment revealed that the SP-history dependence of LL induction of gene expression varies considerably between genes. Some genes were inducible by LL exposure after only 2 weeks exposure to SP, while others required 8 weeks prior SP exposure for maximum responsiveness to LL. Since subsequent SW growth performance is also markedly improved following 8 weeks SP exposure, these photoperiodic history-dependent genes may be useful predictive markers for full smolt development.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Fotoperíodo , Salmo salar/fisiologia , Tolerância ao Sal/genética , Água do Mar/efeitos adversos , Migração Animal/fisiologia , Animais , Brânquias/crescimento & desenvolvimento , Estágios do Ciclo de Vida/fisiologia , Noruega , RNA-Seq , Fatores de Tempo
15.
PLoS One ; 15(3): e0229829, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32187227

RESUMO

BACKGROUND: Aedes albopictus is a major vector for several tropical infectious diseases. Characterization of Ae. albopictus development under natural conditions is crucial for monitoring vector population expansion, dengue virus transmission, and disease outbreak preparedness. METHODS: This study employed mosquito traits as a proxy to understanding life-table traits in mosquitoes using a semi-field study. Ae. albopictus larval and adult life-table experiments were conducted using microcosms under semi-field conditions in Guangzhou. Stage-specific development times and survivorship rates were determined and compared under semi-field conditions in different seasons from early summer (June) to winter (January), to determine the lower temperature limit for larval development and adult survivorship and reproductivity. RESULTS: The average egg- hatching rate was 60.1%, with the highest recorded in October (77.1%; mid-autumn). The larval development time was on average 13.2 days (range, 8.5-24.1 days), with the shortest time observed in September(8.7 days; early autumn) and longest in November (22.8 days). The pupation rates of Ae. albopictus larvae were on average 88.9% (range, 81.6-93.4%); they were stable from June to September but decreased from October to November. The adult emergence rates were on average 82.5% (range, 76.8-87.9%) and decreased from July to November. The median survival time of Ae. albopictus adults was on average 7.4 (range, 4.5-9.8), with the shortest time recorded in September. The average lifetime egg mass under semi-field conditions was 37.84 eggs/female. The larvae could develop into adults at temperatures as low as 12.3°C, and the adults could survive for 30.0 days at 16.3°C and still produce eggs. Overall, correlation analysis found that mean temperature and relative humidity were variables significantly affecting larval development and adult survivorship. CONCLUSION: Ae. albopictus larvae could develop and emerge and the adults could survive and produce eggs in early winter in Guangzhou. The major impact of changes in ambient temperature, relative humidity, and light intensity was on the egg hatching rates, adult survival time, and egg mass production, rather than on pupation or adult emergence rates.


Assuntos
Aedes/crescimento & desenvolvimento , Estágios do Ciclo de Vida/fisiologia , Mosquitos Vetores/crescimento & desenvolvimento , Animais , China , Estações do Ano , Temperatura
16.
Parasitol Res ; 119(2): 749-753, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31897792

RESUMO

Trypanosoma cruzi, the causative agent of Chagas disease, has a complex life cycle that requires the adaptation to different environments. In the absence of traditional mechanisms for regulation of gene expression, this parasite relies on posttranscriptional control events, which allow the progression of its life cycle in different hosts and stress conditions. In this context, different stress conditions trigger the aggregation of RNA-binding proteins and their target mRNAs into cytoplasmic foci known as RNA granules, which act as RNA-sorting centers. In this study, we have characterized the T. cruzi RNA-binding protein ALBA30 during nutritional stress conditions. Using a recombinant form of TcALBA30 to facilitate its detection (rTcALBA30), we showed that this protein resides in the cytoplasm in normal growth conditions but is recruited into cytoplasmic foci after starvation. Moreover, evaluation of rTcALBA30 in parasites that reached the stationary phase of growth also showed the recruitment of this protein into cytoplasmic foci. Our results indicate that, similar to TbALBA3, TcALBA30 aggregates into stress granules in parasites submitted to nutritional stress.


Assuntos
Regulação da Expressão Gênica/genética , Proteínas de Protozoários/genética , Proteínas de Ligação a RNA/genética , Estresse Fisiológico/fisiologia , Trypanosoma cruzi/genética , Animais , Ciclo Celular , Doença de Chagas/parasitologia , Citoplasma/metabolismo , Estágios do Ciclo de Vida/fisiologia , RNA Mensageiro/metabolismo , Inanição
17.
Cell Host Microbe ; 27(2): 290-306.e11, 2020 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-31991093

RESUMO

To survive and proliferate in diverse host environments with varying nutrient availability, the obligate intracellular parasite Toxoplasma gondii reprograms its metabolism. We have generated and curated a genome-scale metabolic model (iTgo) for the fast-replicating tachyzoite stage, harmonized with experimentally observed phenotypes. To validate the importance of four metabolic pathways predicted by the model, we have performed in-depth in vitro and in vivo phenotyping of mutant parasites including targeted metabolomics and CRISPR-Cas9 fitness screening of all known metabolic genes. This led to unexpected insights into the remarkable flexibility of the parasite, addressing the dependency on biosynthesis or salvage of fatty acids (FAs), purine nucleotides (AMP and GMP), a vitamin (pyridoxal-5P), and a cofactor (heme) in both the acute and latent stages of infection. Taken together, our experimentally validated metabolic network leads to a deeper understanding of the parasite's biology, opening avenues for the development of therapeutic intervention against apicomplexans.


Assuntos
Ácidos Graxos/metabolismo , Heme/metabolismo , Toxoplasma/metabolismo , Vitamina B 6/metabolismo , Animais , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Biologia Computacional , Desenvolvimento de Medicamentos/tendências , Genômica , Estágios do Ciclo de Vida/fisiologia , Redes e Vias Metabólicas , Metabolômica , Camundongos , Fenótipo , Toxoplasma/genética
18.
PLoS One ; 15(1): e0227832, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31945116

RESUMO

Here we characterized the development of the trypanosomatid Blastocrithidia raabei in the dock bug Coreus marginatus using light and electron microscopy. This parasite has been previously reported to occur in the host hemolymph, which is rather typical for dixenous trypanosomatids transmitted to a plant or vertebrate with insect's saliva. In addition, C. marginatus has an unusual organization of the intestine, which makes it refractory to microbial infections: two impassable segments isolate the anterior midgut portion responsible for digestion and absorption from the posterior one containing symbiotic bacteria. Our results refuted the possibility of hemolymph infection, but revealed that the refractory nature of the host provokes very aggressive behavior of the parasite and makes its life cycle more complex, reminiscent of that in some dixenous trypanosomatids. In the pre-barrier midgut portion, the epimastigotes of B. raabei attach to the epithelium and multiply similarly to regular insect trypanosomatids. However, when facing the impassable constricted region, the parasites rampage and either fiercely break through the isolating segments or attack the intestinal epithelium in front of the barrier. The cells of the latter group pass to the basal lamina and accumulate there, causing degradation of the epitheliocytes and thus helping the epimastigotes of the former group to advance posteriorly. In the symbiont-containing post-barrier midgut segment, the parasites either attach to bacterial cells and produce cyst-like amastigotes (CLAs) or infect enterocytes. In the rectum, all epimastigotes attach either to the cuticular lining or to each other and form CLAs. We argue that in addition to the specialized life cycle B. raabei possesses functional cell enhancements important either for the successful passage through the intestinal barriers (enlarged rostrum and well-developed Golgi complex) or as food reserves (vacuoles in the posterior end).


Assuntos
Infecções por Euglenozoa/veterinária , Heterópteros/imunologia , Interações Hospedeiro-Parasita/fisiologia , Estágios do Ciclo de Vida/fisiologia , Trypanosomatina/crescimento & desenvolvimento , Animais , Resistência à Doença , Infecções por Euglenozoa/imunologia , Infecções por Euglenozoa/parasitologia , Hemolinfa/parasitologia , Heterópteros/parasitologia , Mucosa Intestinal/diagnóstico por imagem , Mucosa Intestinal/parasitologia , Mucosa Intestinal/ultraestrutura , Microscopia Eletrônica , Trypanosomatina/patogenicidade , Trypanosomatina/ultraestrutura
20.
Parasitol Res ; 119(2): 667-673, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31836921

RESUMO

The development cycle of the malaria parasite, Plasmodium sp., in humans takes place after an infected female Anopheles mosquito injects motile infective forms called sporozoites into the bloodstream. Sporozoites migrate via blood vessels to the liver. This pre-erythrocytic tissue stage is widely accepted to occur in humans exclusively in the liver, contrary to avian malaria where this may occur also in other parenchymatous organs. This concept is based on research conducted by English researchers Henry Shortt and P.C.C. Garnham in the late 1940s. Although Italian researchers as, e.g., Giulio Raffaele, additionally claimed the presence of the parasites in the bone marrow, this is not well acknowledged. So, the question remains whether there exists also a tissue life cycle stage in humans.


Assuntos
Estágios do Ciclo de Vida/fisiologia , Fígado/parasitologia , Plasmodium/crescimento & desenvolvimento , Esporozoítos/crescimento & desenvolvimento , Animais , Anopheles/parasitologia , Feminino , Humanos , Fígado/patologia , Malária Aviária
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