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Circadian changes of Spodoptera littoralis haemocytes
TREFILOVÁ, Terezie
Abstrakt This work is a study of the morphology of hemocytes and stability of the basic non-pathological hematological levels during 24 hours. Spodoptera littoralis. (Boisd.) (Lepidoptera: Noctuidae) in the sixth instar was used as the biological model. Light microscopy was the technique used to observe the hemocytes. Prior to the microscopy, preparations were made from the hemolymph and stained by Pappenheim's staining method. This is a method which is routinely used in veterinary as well as human laboratory practice in hematology. Six types of hemocytes were observed: small granulocytes (sGR), large granulocytes (lGR), small prohemocytes (sPR), large prohemocytes (lPR), spherulocytes (SP), and plasmatocytes (PL). Pappenheim's staining also enabled apoptosis to be followed. The knowledge of circadian changes in hemocytes in S. littoralis is very important if this animal is to be employed as a new biological model, for instance, for investigations in imunology, hematotoxicology or pharmacotoxicology. Changes in the levels of some substances can be physiological even if lying beyond the reference level limits (Knapp et al., 1984). We found the various hemocyte counts varying throughout the day. At midnight, the sPR and lPR counts are lowest while the apoptotic cell and lGR counts are highest. We tested the use of an ELISA reader (Sunrise, Tecan) (which is based on the photometric principle) with a view to increasing the precision and shortening the time of analysis. However, due to the large spans of concentrations, viz. roughly from 2 mmol/l to 30 mmol/l, the use of the ELISA reader was found unsuitable.
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