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The immune response of hemocytes of the insect Oncopeltus fasciatus against the flagellate Phytomonas serpens.

Alves e Silva TL, Vasconcellos LR, Lopes AH, Souto-Padrón T - PLoS ONE (2013)

Bottom Line: The parasites reached the O. fasciatus salivary glands at least six hours post-infection.After 72 hours post-infection, many parasites were attached to the salivary gland outer surface.Thus, the cellular responses did not kill all the parasites.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Bloco I, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, Brazil.

ABSTRACT
The genus Phytomonas includes parasites that are etiological agents of important plant diseases, especially in Central and South America. These parasites are transmitted to plants via the bite of an infected phytophagous hemipteran. Despite the economic impact of these parasites, many basic questions regarding the genus Phytomonas remain unanswered, such as the mechanism by which the parasites cope with the immune response of the insect vector. In this report, using a model of systemic infection, we describe the function of Oncopeltus fasciatus hemocytes in the immune response towards the tomato parasite Phytomonas serpens. Hemocytes respond to infection by trapping parasites in nodular structures and phagocytizing the parasites. In electron microscopy of hemocytes, parasites were located inside vacuoles, which appear fused with lysosomes. The parasites reached the O. fasciatus salivary glands at least six hours post-infection. After 72 hours post-infection, many parasites were attached to the salivary gland outer surface. Thus, the cellular responses did not kill all the parasites.

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The challenge of O.fasciatus with P. serpens induces the formation of nodules.(A) Light microscopy of living hemocytes and parasites 6 h post-infection and (B) Giemsa-stained nodules 72 hpi. The scale bars are the same for both figures A and B, they represent 100× magnification; (C) Scanning electron microscopy of nodules 72 hpi. This figure is equivalent to 1,500× magnification.
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pone-0072076-g005: The challenge of O.fasciatus with P. serpens induces the formation of nodules.(A) Light microscopy of living hemocytes and parasites 6 h post-infection and (B) Giemsa-stained nodules 72 hpi. The scale bars are the same for both figures A and B, they represent 100× magnification; (C) Scanning electron microscopy of nodules 72 hpi. This figure is equivalent to 1,500× magnification.

Mentions: To determine the mechanism by which hemocytes respond to P. serpens challenge, aliquots of hemolymph derived from infected insects were examined using light and scanning electron microscopy. Living parasites were trapped in nodular structures formed by hemocytes as early as 24 hpi (Fig. 5A and 5B). At the same post-infection period, nodules were also observed adhering to the surface of salivary glands (Fig. 5C).


The immune response of hemocytes of the insect Oncopeltus fasciatus against the flagellate Phytomonas serpens.

Alves e Silva TL, Vasconcellos LR, Lopes AH, Souto-Padrón T - PLoS ONE (2013)

The challenge of O.fasciatus with P. serpens induces the formation of nodules.(A) Light microscopy of living hemocytes and parasites 6 h post-infection and (B) Giemsa-stained nodules 72 hpi. The scale bars are the same for both figures A and B, they represent 100× magnification; (C) Scanning electron microscopy of nodules 72 hpi. This figure is equivalent to 1,500× magnification.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756046&req=5

pone-0072076-g005: The challenge of O.fasciatus with P. serpens induces the formation of nodules.(A) Light microscopy of living hemocytes and parasites 6 h post-infection and (B) Giemsa-stained nodules 72 hpi. The scale bars are the same for both figures A and B, they represent 100× magnification; (C) Scanning electron microscopy of nodules 72 hpi. This figure is equivalent to 1,500× magnification.
Mentions: To determine the mechanism by which hemocytes respond to P. serpens challenge, aliquots of hemolymph derived from infected insects were examined using light and scanning electron microscopy. Living parasites were trapped in nodular structures formed by hemocytes as early as 24 hpi (Fig. 5A and 5B). At the same post-infection period, nodules were also observed adhering to the surface of salivary glands (Fig. 5C).

Bottom Line: The parasites reached the O. fasciatus salivary glands at least six hours post-infection.After 72 hours post-infection, many parasites were attached to the salivary gland outer surface.Thus, the cellular responses did not kill all the parasites.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Bloco I, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, Brazil.

ABSTRACT
The genus Phytomonas includes parasites that are etiological agents of important plant diseases, especially in Central and South America. These parasites are transmitted to plants via the bite of an infected phytophagous hemipteran. Despite the economic impact of these parasites, many basic questions regarding the genus Phytomonas remain unanswered, such as the mechanism by which the parasites cope with the immune response of the insect vector. In this report, using a model of systemic infection, we describe the function of Oncopeltus fasciatus hemocytes in the immune response towards the tomato parasite Phytomonas serpens. Hemocytes respond to infection by trapping parasites in nodular structures and phagocytizing the parasites. In electron microscopy of hemocytes, parasites were located inside vacuoles, which appear fused with lysosomes. The parasites reached the O. fasciatus salivary glands at least six hours post-infection. After 72 hours post-infection, many parasites were attached to the salivary gland outer surface. Thus, the cellular responses did not kill all the parasites.

Show MeSH
Related in: MedlinePlus