Insect Hemocytes And Their Role In Immunity – Open Access Policy Institutional Open Access Program Special Issues Guidelines Editorial Process Research and Publication Ethics Article Processing Fees Awards Testimonials
All of his published articles are immediately available worldwide under an open access license. No special permission is required to re-use all or part of the published article, including images and tables. For articles published under the open access Creative Common CC BY license, any part of the article may be reused without permission, as long as the original article is clearly cited. For more information, go to https:///openaccess.
Insect Hemocytes And Their Role In Immunity
Feature papers represent the most advanced research with high potential for significant impact in the field. A feature paper should be an important original article that covers a variety of techniques or approaches, provides insight for future lines of research, and describes possible research applications.
Serotonin Modulates Insect Hemocyte Phagocytosis Via Two Different Serotonin Receptors
Feature papers are submitted by scientific editors by individual invitation or recommendation and must receive positive feedback from reviewers.
Editor’s Choice articles are based on the recommendations of scientific editors from journals around the world. The editors select a small number of recently published articles in the journal that they believe will be of particular interest or relevance to their readers in the area of research. The aim is to provide a snapshot of some of the most exciting work published in the journal’s various research areas.
Author: Maria Luigia Vommaro Maria Luigia Vommaro Scilit Preprints.org Google Scholar 1 , Joachim Kurtz Joachim Kurtz Scilit Preprints.org Google Scholar 2 and Anita Giglio Anita Giglio Scilit Preprints.org Google Scholar 1, *
Received: April 15, 2021 / Revised: May 4, 2021 / Accepted: May 6, 2021 / Published: May 8, 2021
Extracellular Vesicles Secreted By Brugia Malayi Microfilariae Modulate The Melanization Pathway In The Mosquito Host
Tenebrio molitor is a pest of stored grain, causing significant damage. However, the ease of maintenance also makes this species interesting as a food source and as a model for physiological, immunological, ecological and evolutionary studies. We used light and transmission electron microscopy to study the morphology of circulating hemocytes. Prohemocytes, plasmatocytes, granular cells, and enocytoids were described according to their morphological features and staining affinity. The results are the basis for further research to clarify the structure and function of hemocytes in insects.
The immunocompetence of the mealworm Tenebrio molitor has been well studied at the molecular and physiological level, but information on the morphological and functional characteristics of its immune cells (hemocytes) is still scarce and fragmented. This study provides an updated view of the morphology of circulatory cells in adult worm beetles using light and transmission electron microscopy. Hemocytes were defined as eosinophils, basophils, or neutral according to their affinities for May–Grünwald Giemsa stains. Thanks to the ultrastructural description, four main cell types can be recognized in the hemolymph: prohemocytes, plasmatocytes, granular cells and enocytoids. Morphological plasticity of hemocytes and evidence of circulating mitotic cells, intermediate cell stages, and autophagic activity suggest hemocyte proliferation, transformation, and transdifferentiation as ongoing active processes in the hemolymph. Cytochemical tests revealed differences in carbohydrate distribution between cell types, underlying the high plasticity of the immune response and the direct involvement of circulating immune cells in resource allocation. Furthermore, our results provide a detailed morphological description of vesicle trafficking, macro- and microautophagy, apoptotic and necrotic processes, confirming their suitability as a model for studying evolutionarily conserved cellular mechanisms in T. molitor hemocytes.
Insects rely on physical barriers, such as the cuticle, as well as cellular and humoral immune responses, to combat parasites and pathogens in the natural environment [ 1 , 2 ]. Cellular defenses involve hemocytes, clearing pathogens through phagocytosis, nodule formation, encapsulation and cytotoxic reactions [3, 4, 5, 6]. Hemocyte types are mostly referred to morphological, histochemical and functional characteristics [7] or based on monoclonal antibodies and genetic markers [8]. The most common morphological types are prohemocytes, granular cells, plasmatocytes, spherule cells and enocytoids, which appear in species of different insect orders [5, 9, 10, 11, 12, 13]). Humoral effectors are an effective part of the innate immune response and include the production of antimicrobial peptides, the activation of prophenoloxidase (proPO) and the production of reactive oxygen species [ 11 , 14 ]. These effectors cooperate in species-specific pathways that are activated to recognize and neutralize pathogens [ 15 ]. In Drosophila melanogaster, phagocytic plasmatocytes, PO-containing crystal cells and lamellocytes are involved in parasite encapsulation [ 4 , 16 , 17 ]. In Lepidoptera, phagocytic granulocytes, capsule-forming plasmatocytes, spherule cells and PO-containing enocytoids have been identified [4].
Insects such as Diptera, Lepidoptera and Coleoptera are largely used as alternative vertebrate models in physiological, ecological and toxicological studies due to their lack of ethical restrictions, short life cycle and easy maintenance under laboratory conditions [18, 19]. Due to the great structural and functional similarities between the innate immune systems of insects and vertebrates [20, 21], studies of insect immunity can better understand the evolution of innate immune systems [22]. It is also a model for testing chemicals [ 15 , 23 , 24 , 25 ] and bioactive molecules, including antimicrobial peptides [ 26 ] for ecotoxicological and biomedical applications.
Identification Of Silkworm Hemocyte Subsets And Analysis Of Their Response To Bmnpv Infection Based On Single Cell Rna Sequencing
The beetle Tenebrio molitor Linnaeus, 1758 (Coleoptera, Tenebrionidae) is a pest of stored grain facilities. On the other hand, mealworm larvae are used as a source of protein [27, 28] and fatty acids [29] for livestock [30] and human consumption (EU Regulation 2017/983). They are also able to ingest and biodegrade plastic products [31, 32]. Given the growing interest in its use as food and feed, there have been numerous reports investigating the cellular and humoral immune effectors of T. molitor against a wide range of pathogens that reduce its survival and reproductive success, as reviewed [ 33 ]. Hemocyte-mediated cellular responses to biotic challenges have been extensively studied focusing on genes encoding components of the T. molitor immune system [ 34 , 35 , 36 ]. To date, few studies have addressed the morphological and functional variability of T. molitor hemocytes. A previous analysis using phase contrast microscopy has shown three distinct cell types called oenocytoids, plasmatocytes and cystocytes [37]. Scanning electron microscopy, performed to investigate hemopoietic tissues in the adult abdomen, has shown three major morphologically distinct types of hemocytes, namely prohemocytes, granulocytes, and plasmatocytes [38]. Hemocyte responses to biotic (Staphylococcus aureus) and artificial (latex beads) challenges, investigated during developmental stages, have highlighted a fourth morphological type of hemocyte called enocytoid [39].
The aim of this study is to characterize the circulating hemocytes of T. molitor, based on morphological and cytochemical analyses, using light and transmission electron microscopy. We focused our attention on the ultrastructure of subcellular compartments within different populations of circulating hemocytes to update and improve our overall knowledge of their morphological variability.
T. molitor specimens were obtained from a laboratory stock population maintained at the Morphofunctional Entomology Laboratory of the Department of Biology, Ecology and Earth Sciences of the University of Calabria. Meal beetles were reared at 60% relative humidity (rh) under a natural photoperiod and room temperature (23 ± 2) with an ad libitum diet of organic wheat and fruit. In this study, adults were used, 7-10 days after hatching.
Before collecting the hemolymph, the beetles were anesthetized in a cold chamber at 4°C for three minutes. To prepare hemocytes for wet-mount permanent staining, hemolymph (3 μL per specimen) was collected from beetles (n = 12) using a 29-gauge needle at the ventral level of the pro-mesothorax joint. It was mixed with 3 μL of phosphate buffer (PBS, 10 mM pH 7.4; Merck Life Science, Milan, Italy), placed on a poly-L-lysine-coated slide, and processed according to the cytochemical methods indicated below. Except for the in vivo Neutral Red assay, slides were mounted with Eukitt mounting medium (Merck Life Science, Milan, Italy) and examined under a Zeiss Primo Star microscope at 1000× magnification in oil immersion. Light microscopic images of selected areas were acquired with a Redmi note pro 9 mobile phone camera, connected to the eye, with a resolution of 6000 × 8000 pixels.
Innate Immune System
Hemocytes were fixed and embedded as previously described [41]. Briefly, the last two abdominal segments of cold-anesthetized beetles were cut laterally and sterile PBS was slowly injected by puncturing the cervical membrane with a 29-gauge needle. Hemolymph was rapidly drained from the abdomen into a microcentrifuge tube containing fixative (2.5% glutaraldehyde and 1% paraformaldehyde in 0.1 M phosphate buffer, pH 7.4, 1.5% sucrose). A pool of 20 μL of hemolymph was collected from five different samples and kept at 4°C overnight. All samples were centrifuged at 1700 × g for 5 min and the supernatant removed. Pellets were washed with 1.5% sucrose in PBS, washed with 1% osmium tetroxide in 0.1 M PBS for 2 h at 4°C, then washed in the same buffer. Dehydration of the pellets in a graded acetone series was embedded in epoxy resin (Merck Life Science, Milan, Italy). Ultrathin sections, cut with a PT-PC Power Tome Ultramicrotome (RMC Boeckeler, Groot-Ammers, The Netherlands, with a Jeol JEM 1400 Plus electron microscope (Center for Microscopy and Microanalysis, CM2, Transmission Electron Microscopy Laboratory — University of Calabria, Italy) at 60 kV . Measurements have been taken
What role do antibodies play in immunity, role of thymus in immunity, sports role models and their impact, candida biofilms and their role in infection, the role of antigen presenting cells in immunity is to, lymphatic system role in immunity, insect pheromones and their application, insect pheromones and their use in pest management, insect pests of rice and their management, milk enzymes their role and significance, insect pictures and their names, role of nk cells in immunity
