![]() However, a decrease in the numbers of hemocytes was reported more often (e.g., 21 reports). Total hemocyte counts may increase or decrease in response to plant-derived chemicals. Jus and 14 reporting the effects of various plant extracts or essential oils. An extensive review by Ghoneim (2018) lists 29 contributions, 15 devoted to the effects of products from Azadirachta indica A. 2010) to modulation of immune response to plant volatiles ( Ghosh and Venkatesan 2019).ĭuring the last decade, progress has been made in studies on the effects of plant-derived products on insect hemocytes. 2002), and this technique is used presently in works ranging from evaluating encapsulation rates in insects upon bacterial infection ( Dubovskii et al. More recently, digital videography analyzed with computer-aided image analysis was used for measuring grey values ( Rantala et al. Later, video imaging systems measuring grey values of light passing through the implants were introduced ( Köning and Schmid-Hempel 1995). Historically, the presence of hemocyte layers covering the implants, visualized by transmission electron microscopy, was evidence of encapsulation ( Akai and Sato 1973). Failure to encapsulate equates to failure of the immune system ( Webb and Luckhart 1996). The encapsulation response is a general measure of immune function requiring the coordination of many cellular and humoral immune effector systems into a single, easily measured response ( Dubovskiy et al. Implants made of nylon thread were used to demonstrate encapsulation and melanization in B. India ink also increased granulocyte counts in Dermatobia hominis L. Wigglesworth (1956) reported an “enormous increase” in the numbers of Rhodnius prolixus Stål hemocytes in response to injected India ink. However, changes in hemocyte counts after ink injections were studied as well. ( Lea and Gilbert 1966), or Drosophila sp. Most authors concentrated on the phagocytosis of ink particles in B. mellonella by Cameron as early as 1934, although literature on this topic is scarce. Effects of ink on insect hemocytes were studied in G. Many abiotic agents (among them ink and nylon thread or monofilament) may act as immunomodulators in insects ( Shaurub 2013). 1993), and inoculation with Candida albicans (Robin) Berkhout does the same in G. Infection with Pseudomonas aeruginosa (Schroeter) Migula lowers total hemocyte counts in Apis mellifera macedonica L. mellonella and Heliothis zea (Boddie) infected with a nucleopolyhedrosis virus ( Shapiro 1968a Shapiro et al. ![]() A similar response was observed in larval G. also resulted in a reduction of the total circulating hemocyte numbers ( Laigo and Paschke 1966). Infection of Trichoplusia ni larvae with Nosema sp. (2014) reported the same for Bacillus thuringiensis Berliner. (Lepidoptera: Pyralidae) larvae react to infection with the bacterium Bacillus cereus Frankland and Frankland by lowering the total numbers of circulating hemocytes ( Ratcliffe and Walters 1983). The character of this change depends on insect species and the intruder. Hemocyte numbers in insect hemolymph can rapidly change in response to infection ( Lackie 1988 Ratcliffe et al. In the former case, citral concentrations needed for effective inhibition were less (0.3 µg/larva) than in ink-challenged larvae (1.2 and 2.4 µg/larva). Citral injections inhibited implant melanization both in unchallenged and ink-challenged larvae. The degree of melanization also was higher in larvae challenged with ink 1 h prior to implant removal, which suggests initialization of the immune response. Melanization of nylon larvae implants started as early as 15 min after implant insertion and reached maximum observed levels within 1 h. Lemongrass essential oil (0.18, 0.36, and 0.72 µg/larva) and citral (0.12, 0.24, and 0.48 µg/larva) reversed the mobilization of hemocytes by the ink. Hemocyte numbers increased significantly at 4 and 6 h after ink injection. Ink injections increased total hemocyte counts in a dose-dependent manner, with the 40 and 80% concentrations being most effective in eliciting hemocyte response. (Lepidoptera: Pyralidae) last-instar larvae. We studied the effects of carbon particles (Sumi ink) on the immune response of Galleria mellonella L. In most lepidopteran species, challenging the immune system causes an increase in hemocyte numbers and promotes encapsulation and melanization of invading objects, such as parasitoid eggs or artificial objects (e.g., nylon implants). The innate immune response in insects relies on cellular responses.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |