80 research outputs found

    Ticks as potential vectors of Mycobacterium leprae: Use of tick cell lines to culture the bacilli and generate transgenic strains.

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    Leprosy is an infectious disease caused by Mycobacterium leprae and frequently resulting in irreversible deformities and disabilities. Ticks play an important role in infectious disease transmission due to their low host specificity, worldwide distribution, and the biological ability to support transovarial transmission of a wide spectrum of pathogens, including viruses, bacteria and protozoa. To investigate a possible role for ticks as vectors of leprosy, we assessed transovarial transmission of M. leprae in artificially-fed adult female Amblyomma sculptum ticks, and infection and growth of M. leprae in tick cell lines. Our results revealed M. leprae RNA and antigens persisting in the midgut and present in the ovaries of adult female A. sculptum at least 2 days after oral infection, and present in their progeny (eggs and larvae), which demonstrates the occurrence of transovarial transmission of this pathogen. Infected tick larvae were able to inoculate viable bacilli during blood-feeding on a rabbit. Moreover, following inoculation with M. leprae, the Ixodes scapularis embryo-derived tick cell line IDE8 supported a detectable increase in the number of bacilli for at least 20 days, presenting a doubling time of approximately 12 days. As far as we know, this is the first in vitro cellular system able to promote growth of M. leprae. Finally, we successfully transformed a clinical M. leprae isolate by inserting the reporter plasmid pCHERRY3; transformed bacteria infected and grew in IDE8 cells over a 2-month period. Taken together, our data not only support the hypothesis that ticks may have the potential to act as a reservoir and/or vector of leprosy, but also suggest the feasibility of technological development of tick cell lines as a tool for large-scale production of M. leprae bacteria, as well as describing for the first time a method for their transformation

    Composições microbicidas, processos para sua obtenção, construções gênicas, processos para o controle de pestes

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    Em 17/03/2016: Anuidade de pedido de patente de invenção no prazo ordinárioDepositadaA presente invenção é relacionada a fatores antimicrobianos extraídos de envoltórios protetores (cascas) de ovos de insetos. A maioria destes fatores compreende peptídeos e/ou proteínas obtidas de tais involuntários e/ou de seus respectivos genes codificantes, em construções gênicas artificiais. São descritas composições microbicidas e processos para sua obtenção, bem como construções gênicas e processos para o controle de pestes

    Calreticulin expression levels and endoplasmic reticulum during late oogenesis and early embryogenesis of rhodnius prolixus stahl

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    11 p. : il.This study reports the cloning, expression analysis and localization of calreticulin (CRT) in the endoplasmic reticulum (ER) during late oogenesis and early embryogenesis of the insect Rhodnius prolixus. CRT was cloned and sequenced from cDNA extracted from unfertilized eggs. Real-time PCR showed that CRT expression remains at lower levels during late oogenesis when compared to vitellogenic oocytes or day 0 laid fertilized eggs. Immunofluorescence microscopy showed that this protein is located in the periphery of the egg, in a differential peripheral ooplasm surrounding the yolk-rich internal ooplasm, only identified by transmission electron microscopy (TEM) of thin sections. Using immunogold electron microscopy, the ER ultrastructure (CRT labeled) was identified in the peripheral ooplasm as dispersed lamellae, randomly distributed in the peripheral ooplasm. No massive alterations of ER ultrastructure were found before or right after (30 min) fertilization, but an increase in CRT expression levels and assembly of typical rough ER (parallel cisternae with associated ribosomes) were observed 18–24 h after oviposition. The lack of ER assembly at fertilization and the later formation of rough ER together with the increase in CRT expression levels, suggest that the major functions of ER might be of great importance during the early events of development. The possible involvement of ER in the early steps of embryogenesis will be discussed
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