Colonisation resistance in the sand fly gut:Leishmania protects Lutzomyia longipalpis from bacterial infection

BACKGROUND: Phlebotomine sand flies transmit the haemoflagellate Leishmania, the causative agent of human leishmaniasis. The Leishmania promastigotes are confined to the gut lumen and are exposed to the gut microbiota within female sand flies. Here we study the colonisation resistance of yeast and bacteria in preventing the establishment of a Leishmania population in sand flies and the ability of Leishmania to provide colonisation resistance towards the insect bacterial pathogen Serratia marcescens that is also pathogenic towards Leishmania. METHODS: We isolated microorganisms from wild-caught and laboratory-reared female Lutzomyia longipalpis, identified as Pseudozyma sp. Asaia sp. and Ochrobactrum intermedium. We fed the females with a sugar meal containing the microorganisms and then subsequently fed them with a bloodmeal containing Leishmania mexicana and recorded the development of the Leishmania population. Further experiments examined the effect of first colonising the sand fly gut with L. mexicana followed by feeding with, Serratia marcescens, an insect bacterial pathogen. The mortality of the flies due to S. marcescens was recorded in the presence and absence of Leishmania. RESULTS: There was a reduction in the number of flies harbouring a Leishmania population that had been pre-fed with Pseudozyma sp. and Asaia sp. or O. intermedium. Experiments in which L. mexicana colonised the sand fly gut prior to being fed an insect bacterial pathogen, Serratia marcescens, showed that the survival of flies with a Leishmania infection was significantly higher compared to flies without Leishmania infection. CONCLUSIONS: The yeast and bacterial colonisation experiments show that the presence of sand fly gut microorganisms reduce the potential for Leishmania to establish within the sand fly vector. Sand flies infected with Leishmania were able to survive an attack by the bacterial pathogen that would have killed the insect and we concluded that Leishmania may benefit its insect host whilst increasing the potential to establish itself in the sand fly vector. We suggest that the increased ability of the sand fly to withstand a bacterial entomopathogen, due to the presence of the Leishmania, may provide an evolutionary pressure for the maintenance of the Leishmania-vector association

Currents issues in cardiorespiratory care of patients with post-polio syndrome

Post-polio syndrome (PPS) is a condition that affects polio survivors years after recovery from an initial acute attack of the poliomyelitis virus. Most often, polio survivors experience a gradual new weakening in muscles that were previously affected by the polio infection. The actual incidence of cardiovascular diseases (CVDs) in individuals suffering from PPS is not known. However, there is a reason to suspect that individuals with PPS might be at increased risk. Method: A search for papers was made in the databases Bireme, Scielo and Pubmed with the following keywords: post polio syndrome, cardiorespiratory and rehabilitation in English, French and Spanish languages. Although we targeted only seek current studies on the topic in question, only the relevant (double-blind, randomized-controlled and consensus articles) were considered. Results and Discussion: Certain features of PPS such as generalized fatigue, generalized and specific muscle weakness, joint and/or muscle pain may result in physical inactivity deconditioning obesity and dyslipidemia. Respiratory difficulties are common and may result in hypoxemia. Conclusion: Only when evaluated and treated promptly, somE patients can obtain the full benefits of the use of respiratory muscles aids as far as quality of life is concerned.Ctr Univ Augusto Motta, Programa Posgrad Ciencias Reabilitacao, Rio De Janeiro, RJ, BrazilUniv Severino Sombra, Fac Med, Vassouras, RJ, BrazilUniv Fed Rio de Janeiro, Inst Psiquiatria, Lab Mapeamento Cerebral & EEG, BR-22290140 Rio De Janeiro, RJ, BrazilUniv Fed Fluminense, Hosp Univ Antonio Pedro, Niteroi, RJ, BrazilInst Fed Educ Ciencia & Tecnol Rio de Janeiro, Curso Fisioterapia, Rio De Janeiro, RJ, BrazilUniv Fed Piaui, Parnaiba, PI, BrazilUniv Fed Sao Paulo, Dept Neurol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Neurol, Sao Paulo, SP, BrazilWeb of Scienc

Reactive Oxygen Species-mediated Immunity against Leishmania mexicana and Serratia marcescens in the Phlebotomine Sand Fly Lutzomyia longipalpis

Phlebotomine sand flies are the vectors of medically important Leishmania. The Leishmania protozoa reside in the sand fly gut, but the nature of the immune response to the presence of Leishmania is unknown. Reactive oxygen species (ROS) are a major component of insect innate immune pathways regulating gut-microbe homeostasis. Here we show that the concentration of ROS increased in sand fly midguts after they fed on the insect pathogen Serratia marcescens but not after feeding on the Leishmania that uses the sand fly as a vector. Moreover, the Leishmania is sensitive to ROS either by oral administration of ROS to the infected fly or by silencing a gene that expresses a sand fly ROS-scavenging enzyme. Finally, the treatment of sand flies with an exogenous ROS scavenger (uric acid) altered the gut microbial homeostasis, led to an increased commensal gut microbiota, and reduced insect survival after oral infection with S. marcescens. Our study demonstrates a differential response of the sand fly ROS system to gut microbiota, an insect pathogen, and the Leishmania that utilize the sand fly as a vehicle for transmission between mammalian hosts

Reactive oxygen species scavenging by catalase is important for female lutzomyia longipalpis fecundity and mortality

The phlebotomine sand fly Lutzomyia longipalpis is the most important vector of American visceral leishmaniasis (AVL), the disseminated and most serious form of the disease in Central and South America. In the natural environment, most female L. longipalpis are thought to survive for less than 10 days and will feed on blood only once or twice during their lifetime. Successful transmission of parasites occurs when a Leishmania-infected female sand fly feeds on a new host. Knowledge of factors affecting sand fly longevity that lead to a reduction in lifespan could result in a decrease in parasite transmission. Catalase has been found to play a major role in survival and fecundity in many insect species. It is a strong antioxidant enzyme that breaks down toxic reactive oxygen species (ROS). Ovarian catalase was found to accumulate in the developing sand fly oocyte from 12 to 48 hours after blood feeding. Catalase expression in ovaries as well as oocyte numbers was found to decrease with age. This reduction was not found in flies when fed on the antioxidant ascorbic acid in the sugar meal, a condition that increased mortality and activation of the prophenoloxidase cascade. RNA interference was used to silence catalase gene expression in female Lu. longipalpis. Depletion of catalase led to a significant increase of mortality and a reduction in the number of developing oocytes produced after blood feeding. These results demonstrate the central role that catalase and ROS play in the longevity and fecundity of phlebotomine sand flies

Saliva of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) inhibits classical and alternative complement pathways

Submitted by Sandra Infurna ([email protected]) on 2016-12-28T13:06:47Z No. of bitstreams: 1 vladimir2_vale_etal_IOC_2016.pdf: 1407380 bytes, checksum: 44c0e6c82133635ffa1999c181a24071 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2016-12-28T13:24:29Z (GMT) No. of bitstreams: 1 vladimir2_vale_etal_IOC_2016.pdf: 1407380 bytes, checksum: 44c0e6c82133635ffa1999c181a24071 (MD5)Made available in DSpace on 2016-12-28T13:24:29Z (GMT). No. of bitstreams: 1 vladimir2_vale_etal_IOC_2016.pdf: 1407380 bytes, checksum: 44c0e6c82133635ffa1999c181a24071 (MD5) Previous issue date: 2016Universidade Federal de Minas Gerais. Departamento de Parasitologia. Laboratório de Fisiologia de Insetos Hematófagos. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Departamento de Parasitologia. Laboratório de Fisiologia de Insetos Hematófagos. Belo Horizonte, MG, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Simulídeos e Oncocercose. Rio de Janeiro, RJ, Brasil.Universidade Federal de Minas Gerais. Departamento de Parasitologia. Laboratório de Fisiologia de Insetos Hematófagos. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Departamento de Parasitologia. Laboratório de Fisiologia de Insetos Hematófagos. Belo Horizonte, MG, Brasil / Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular. Rio de Janeiro, RJ, Brasil.National Institute of Allergy and Infectious Diseases, NIH. Vector Molecular Biology Section. LMVR. Rockville, MD, USA.Universidade Federal de Minas Gerais. Departamento de Parasitologia. Laboratório de Fisiologia de Insetos Hematófagos. Belo Horizonte, MG, Brasil / Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular. Rio de Janeiro, RJ, Brasil.Universidade Federal de Minas Gerais. Departamento de Parasitologia. Laboratório de Fisiologia de Insetos Hematófagos. Belo Horizonte, MG, Brasil.Empresa de Pesquisa Agropecuária de Minas Gerais. Fazenda Experimental Santa Rita. Prudente de Morais, MG.Universidade Federal de Minas Gerais. Departamento de Parasitologia. Laboratório de Fisiologia de Insetos Hematófagos. Belo Horizonte, MG, Brasil.Universidade Federal do Espírito Santo. Departamento de Patologia. Vitória, ES, Brasil.Universidade Federal de Minas Gerais. Departamento de Parasitologia. Laboratório de Fisiologia de Insetos Hematófagos. Belo Horizonte, MG, Brasil / Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular. Rio de Janeiro, RJ, Brasil.Rhipicephalus (Boophilus) microplus is the main ectoparasite affecting livestock worldwide. For a successful parasitism, ticks need to evade several immune responses of their hosts, including the activation of the complement system. In spite of the importance of R. microplus, previous work only identified one salivary molecule that blocks the complement system. The current study describes complement inhibitory activities induced by R. microplus salivary components and mechanisms elicited by putative salivary proteins on both classical and alternative complement pathways

Genomic analysis of two phlebotomine sand fly vectors of Leishmania from the New and Old World.

Phlebotomine sand flies are of global significance as important vectors of human disease, transmitting bacterial, viral, and protozoan pathogens, including the kinetoplastid parasites of the genus Leishmania, the causative agents of devastating diseases collectively termed leishmaniasis. More than 40 pathogenic Leishmania species are transmitted to humans by approximately 35 sand fly species in 98 countries with hundreds of millions of people at risk around the world. No approved efficacious vaccine exists for leishmaniasis and available therapeutic drugs are either toxic and/or expensive, or the parasites are becoming resistant to the more recently developed drugs. Therefore, sand fly and/or reservoir control are currently the most effective strategies to break transmission. To better understand the biology of sand flies, including the mechanisms involved in their vectorial capacity, insecticide resistance, and population structures we sequenced the genomes of two geographically widespread and important sand fly vector species: Phlebotomus papatasi, a vector of Leishmania parasites that cause cutaneous leishmaniasis, (distributed in Europe, the Middle East and North Africa) and Lutzomyia longipalpis, a vector of Leishmania parasites that cause visceral leishmaniasis (distributed across Central and South America). We categorized and curated genes involved in processes important to their roles as disease vectors, including chemosensation, blood feeding, circadian rhythm, immunity, and detoxification, as well as mobile genetic elements. We also defined gene orthology and observed micro-synteny among the genomes. Finally, we present the genetic diversity and population structure of these species in their respective geographical areas. These genomes will be a foundation on which to base future efforts to prevent vector-borne transmission of Leishmania parasites