Hemocoelic inoculation of epimastigotes of Trypanosoma rangeli strain H14 into 5th-instar larvae of Rhodnius prolixus previously fed on blood containing the same parasites, showed reduced number of hemocyte microaggregates in the hemolymph, enhanced number of flagellates in the hemolymph as well as increased mortality of these insects. All these effects were counteracted by combined inoculation of R. prolixus with T. rangeli and arachidonic acid. In vitro assays using hemolymph taken from insects previously fed on blood containing parasites showed that hemocyte microaggregation reactions were also attenuated when T. rangeli is used as inducer of the reaction, and that simultaneous applying T. rangeli with arachidonic counteracted the hemocyte microaggregation inhibition. We suggest that arachidonic acid pathway can be a mediator of hemocyte microaggregation reactions in the hemolymph of insects inoculated with T. rangeli, and that oral infection with this protozoan inhibits the release of arachidonic acid.
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http://dx.doi.org/10.1016/j.exppara.2004.03.015 | DOI Listing |
Front Physiol
August 2024
Programa de Pós-Graduação em Ciências e Biotecnologia, Universidade Federal Fluminense, Niterói, Brazil.
Introduction: is a hematophagous insect and one of the main vectors for and parasites in Latin America. Gut microbiota and insect immune responses affect and infection within triatomines. Particularly the Toll and IMD signaling pathways activations and how they orchestrate the antimicrobial peptides (AMPs) expressions in , especially when infected by .
View Article and Find Full Text PDFInsect Sci
August 2024
Post Graduate Department of Zoology, Banwarilal Bhalotia College, Asansol, Paschim Bardhaman, West Bengal, India.
Viruses, bacteria, fungus, protozoans, and different metazoan parasites and parasitoids present a constant threat to insects. Insect immunity has two components: humoral and cell mediated. Humoral immunity can be achieved by various antimicrobial proteins, namely, cecropins, sarcotoxin, defensin, attacin, etc.
View Article and Find Full Text PDFInsects
November 2023
Biological Control of Insects Research Laboratory, USDA, Agricultural Research Service, Columbia, MO 65203, USA.
Insect innate immunity is composed of cellular and humoral reactions, the former acting via circulating hemocytes and the latter via immune signaling that lead to the production of antimicrobial peptides and phenol oxidase-driven melanization. Cellular immunity involves direct interactions between circulating hemocytes and invaders; it includes internalization and killing microbes (phagocytosis) and formation of bacterial-laden microaggregates which coalesce into nodules that are melanized and attached to body walls or organs. Nodulation can entail investing millions of hemocytes which must be replaced.
View Article and Find Full Text PDFFront Immunol
November 2022
School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan, China.
polysaccharides (PS) have been used as Chinese traditional medicine with various pharmacological effects, including antiviral, anti-oxidative, and immunomodulatory activities. Herein silkworm was used as a model animal to evaluate the immunomodulatory effects of PS detecting the changes of innate immune parameters and explore the underlying molecular mechanism of the immunoregulatory effect of PS using Illumina HiSeq Xten platform. The results presented here demonstrated that a hemocoel injection of PS significantly enhanced the cellular immunity of silkworm, including hemocyte phagocytosis, microaggregation, and spreading ability.
View Article and Find Full Text PDFFront Immunol
February 2022
Department of Plant Medicals, Andong National University, Andong, South Korea.
Innate immune responses are effective for insect survival to defend against entomopathogens including a fungal pathogen, , that infects a lepidopteran . In particular, the fungal virulence was attenuated by cellular immune responses, in which the conidia were phagocytosed by hemocytes (insect blood cells) and hyphal growth was inhibited by hemocyte encapsulation. However, the chemokine signal to drive hemocytes to the infection foci was little understood.
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