• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.11-14
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• 2003

Systemic fungicides viz., Bavistin and Beyleton are reported to have curative effect against the infection of Beauveria bassiana in silkworm Bombyx mori L. To understand the influence of the systemic fungicides on the disease suppression/development, hematological studies were carried out. There was an increase in the percent total hemocyte count, granulocyte and plasmatocyte in silkworm treated with the systemic fungicides. It possibly indicates the influence of systemic fungicide on the hemocyte mediated defense system leading to the higher resistance and suppression of disease development.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.189-194
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• 2002

Silkworm diseases are major constraint in silk cocoon production. Among silkworm diseases, white muscar-dine is highly contagious and most common in winter and rainy seasons. It is suggested that hemocytes involve in defense against invasion of Beauveria bassi-ana and systemic fungicide/chemicals prevent the proliferation of fungi in the hemolymph or preventing the growth of the fungi in the body cavity through enhancing the hemocyte mediated defense response. In the present study the influence of systemic fungicide on hematological changes in silkworms infected with Beauveria bassiana was reported. It is observed that the total hemocyte counts increased in the hemolymph up to 5 days post inoculation in systemic fungicide treated batches while in the inoculated control the increase was up to 3 days indicating the positive hemocyte mediated response in silkworm treated with systemic fungicide. After 2 days in the inoculated control as the multiplication and growth of mycelia increased, defense capacity of the silkworm was decreased. The biochemical changes were also observed in the hemolymph of silkworm infected with B. bassiana. In silkworm infected with Beauveria bassi-ana, the total protein content increased whereas total carbohydrate and total lipids decreased as the infection progresses. In the case of systemic fungicide treated batches the increase in total protein content was comparatively higher and decrease in total carbohydrate and lipids were comparatively lower than the inoculated control.

• BMB Reports
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• v.43 no.4
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• pp.279-283
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• 2010

Polydnavirus genome is segmented and dispersed on host wasp chromosome. After replication, the segments form double- stranded circular DNAs and embedded in viral coat proteins. These viral particles are delivered into a parasitized host along with parasitoid eggs. A serine-rich protein (SRP) is predicted in a polydnavirus, Cotesia plutellae bracovirus (CpBV), genome in its segment no. 33 (CpBV-S33), creating CpBV-SRP1. This study explored its expression and physiological function in the diamondback moth, Plutella xylostella, larvae parasitized by C. plutellae. CpBV-SRP1 encodes 122 amino acids with 26 serines and several predicted phosphorylation sites. It is persistently expressed in all tested tissues of parasitized P. xylostella including hemocyte, fat body, and gut. Its physiological function was analyzed by injecting CpBV-S33 and inducing its expression in nonparasitized P. xylostella by a technique called SERI (segment expression and RNA interference). The expression of CpBV-SRP1 significantly impaired the spreading behavior and total cell count of hemocytes of treated larvae. Subsequent RNA interference of CpBV-SRP1 rescued the immunosuppressive response. This study reports the persistent expression of CpBV-SRP1 in a parasitized host and its parasitic role in suppressing the host immune response by altering hemocyte behavior and survival.

• Journal of fish pathology
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• v.24 no.1
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• pp.19-27
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• 2011

The production of surf clam, Mactra veneriformis, an important fishery resource in Korea, has recently been decreasing. This study was carried out to examine effects of spawning on immune functions of this species. Total hemocyte count (THC), phenoloxidase (PO) activity, phagocytic activity, neutral red retention (NRR) time and antibacterial activity were assessed. Spawned clams showed reduction in THC, PO, phagocytic activity and NRR times compared with unspawned ones. While spawning event did not elicit any change of antibacterial activity in both spawned and unspawned ones. This study indicates that spawning process decreases immune functions in the surf clams which could cause mortality increment and yield reduction.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.164-170
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• 2007

The concept of innate immunity in insects which refers to the first line of host defense constitutes the humoral and cellular components which are involved in recognition and actively participate in the elimination of the intruding foreign micro- or macro-organisms. Several recent studies suggest that juvenile hormone (JH) modulates the cellular immune reactions in response to pathogen. In this study, pyriproxyfen (a JH agonist as an insect growth regulator) was tested in its any inhibitory effect on the immune reactions of the beet armyworm, Spodoptera exigua. To this end, five different hemocyte morphotypes of final instar S. exigua were identified by phase contrast microscopy. Plasmatocytes and granular cells, which constitute about 90% of the total hemocyte count, were prominently distinguished based on their basophilic/acidophilic nature using Giemsa stain. The role of pyriproxyfen on the functional ability of hemocytes was analyzed using FITC-labeled Providencia vermicola for the phagocytic potential of the hemocytes. Both granular cells and plasmatocytes exhibited phagocytosis behavior. Pyriproxyfen significantly inhibited the phagocytosis of both cell types, proposing its novel action as an immunosuppressant.