Brief Laboratory Report About Infection Of An Insect With A Bacterium (Lab Report Sample)

Exercise V: Hematological Techniques
Telan, Jose Angel Jude B 5/28/18 ENT 275
-2257821858100Abstract
-64770226758500Hemocyte present in the insect hemocoel could be inspected and observed to assess the health of an insect. This is why knowledge regarding hematological techniques are important especially in the field of insect pathology as it could help in diagnosing insect diseases. This experiment aims to get the students familiarized with various hemocyte forms present in the hemolymph of heathy insects using basic hematological techniques. Spodoptera litura larvae were utilized for this experiment. Successful extraction of the hemolymph involved a minor amputation of the prolegs to allow hemolymph to be collected even without using pressure on the microcentrifuge tube. The collected hemolymph samples were diluted, and some were subjected to total hemocyte count using a micrometer and some samples were observed for differential hemocyte count. Total hemocyte count amounted to 2.16x107 while the resulting differential count were as follows: 25% prohemocyte, 31.08% plasmatocyte, 18.92% spherulocyte, 13.51% oenocyte, and 11.49% granulocyte. These data show that students were able to get familiarized in using hematological techniques on a healthy insect specimen.
Introduction
Some insect pathogens usually proliferate in the gut and inside the hemocoel, where hemolymph mainly flows. Nutrients present in the gut and hemocoel allow these pathogens to develop and reproduce. (Wei et al. 2017; Singh et al. 2014) Thus, the hemolymph composition of an insect could be observed for indications for certain infections. These indications could aid in diagnosing insect diseases and thus provide information towards the health of the insect specimen (Pandey & Tiwari, 2012). In this experiment, students should be familiarized to the different hemocyte forms present in the hemolymph of healthy insects and also should be familiarized to basic hematological techniques for insects.
Materials and methods
Spodoptera litura larvae used for this experiment were individuals reared by the UPLB Insectary. These larvae were prepared by immersion in water with the temperature of 55 degrees Celsius for one minute, which was dried on paper towel afterwards. The first part of the experiment involved the total hemocyte count. The first pair of prolegs were cut in order for the hemolymph to drop without pressure. This drop should be collected in a microcentrifuge tube. This hemolymph will be diluted ten-fold in 0.85% saline solution in another microcentrifuge tube then set aside. A Hemocyometer was prepared by cleaning with 70% ethanol. Cover glass was placed on the counting chamber ensuring close contact with the supporting ribs. Using a micropipette, the previously prepared hemolymph was drawn into the space between the cover glass and ruled area of the slide. Avoid any overflows and let the slide stand for one minute. The hemocytes on the four corner 1mm squares and central ruled area of the slide will be observed and counted under the microscope. The total cell count will be computed using the formula:
Average hemocyte count per 1mm square x dilution x 104
After cleaning the counting chamber using soap and water then drying, the differential hemocyte count will be performed. Same methods were used to collect the hemolymph from the insect larvae. Ethanol cleaned slide were used to prepare a thin hemolymph film by making a smear using two microscope slides. The hemolymph film was air-dried and was stained by fixing in methanol for 2-5mins, air-dried, then covered with Giemsa stain for 1-2mins, washed with deionized water for 2-4mins, and lastly rinsed with distilled water and air-dried. After the smear preparation, cover slip was placed on the slide and observed under oil immersion objective of the microscope. Hemocyte types were noted during the observation.
Results and Discussion
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041592500On the differential hemocyte count, the percentage of the hemocyte forms are as follows: 25% prohemocyte, 31.08% plasmatocyte, 18.92% spherulocyte, 13.51% oenocyte, and 11.49% granulocyte out
0175260Figure SEQ Figure \* ARABIC 1a and 1b. Left side photo shows A (prohemocyte), B (plasmatocyte), C (spherulocyte), D (oenocyte), and E (granulocyte) while ...