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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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P.serpens reaches the salivary gland of O. fasciatus.(A). Anatomy of the O. fasciatus salivary gland. The arrows show: lateral lobes (L.L.), posterior lobes (P.L.), anterior lobes (A.L.), accessory glands (A.G.), salivary duct (S.D.) and hilus (H). (B). SEM of infected salivary glands at 24 hpi. (C) Salivary glands infected with long slender forms at 72 hpi.
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pone-0072076-g009: P.serpens reaches the salivary gland of O. fasciatus.(A). Anatomy of the O. fasciatus salivary gland. The arrows show: lateral lobes (L.L.), posterior lobes (P.L.), anterior lobes (A.L.), accessory glands (A.G.), salivary duct (S.D.) and hilus (H). (B). SEM of infected salivary glands at 24 hpi. (C) Salivary glands infected with long slender forms at 72 hpi.

Mentions: The number of parasites in the hemolymph was determined at 24, 48, 72, 96 and 120 hpi. The parasites multiplied in the hemolymph (Fig. 2A and 2B). The parasites reached the peak of parasitemia at 72 hpi. At this time point, two populations of parasites were observed (Fig. 3A), a population with an average cell body length of 16.7 (±0.6) µm and long slender parasites with an average cell body length of 54.8 (±6.4) µm (Fig. 3B). As there is no definition for long slender forms in the literature, we considered as a long slender parasite any parasite with a cell body length over 30 µm. After 72 hours, approximately 40% of the parasites in the circulation and almost 100% of the parasites attached to the salivary glands were long slender promastigotes (Fig. 3B and 9C).


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)

P.serpens reaches the salivary gland of O. fasciatus.(A). Anatomy of the O. fasciatus salivary gland. The arrows show: lateral lobes (L.L.), posterior lobes (P.L.), anterior lobes (A.L.), accessory glands (A.G.), salivary duct (S.D.) and hilus (H). (B). SEM of infected salivary glands at 24 hpi. (C) Salivary glands infected with long slender forms at 72 hpi.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0072076-g009: P.serpens reaches the salivary gland of O. fasciatus.(A). Anatomy of the O. fasciatus salivary gland. The arrows show: lateral lobes (L.L.), posterior lobes (P.L.), anterior lobes (A.L.), accessory glands (A.G.), salivary duct (S.D.) and hilus (H). (B). SEM of infected salivary glands at 24 hpi. (C) Salivary glands infected with long slender forms at 72 hpi.
Mentions: The number of parasites in the hemolymph was determined at 24, 48, 72, 96 and 120 hpi. The parasites multiplied in the hemolymph (Fig. 2A and 2B). The parasites reached the peak of parasitemia at 72 hpi. At this time point, two populations of parasites were observed (Fig. 3A), a population with an average cell body length of 16.7 (±0.6) µm and long slender parasites with an average cell body length of 54.8 (±6.4) µm (Fig. 3B). As there is no definition for long slender forms in the literature, we considered as a long slender parasite any parasite with a cell body length over 30 µm. After 72 hours, approximately 40% of the parasites in the circulation and almost 100% of the parasites attached to the salivary glands were long slender promastigotes (Fig. 3B and 9C).

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