A Hemocyte Disturbance Assay to Assess Hemocyte Re-Adhesion to Hematopoietic Pockets
Published: January 31, 2024
Abstract
Source: Petraki, S. et al., Assaying Blood Cell Populations of the Drosophila melanogaster Larva. J. Vis. Exp. (2015)
This video demonstrates the hemocyte disturbance assay, evaluating hemocyte re-adhesion in Drosophila larvae's hematopoietic pockets. Mechanical disturbance releases resident hemocytes, elevating circulating hemocyte counts. Post-recovery, re-adherence of resident hemocytes is confirmed, illustrating reversibility.
Protocol
1. Hemocyte Bleed/Scrape Assay Preparation of slides: Option 1 for microscopes without tile scanning function: For each larva to be analyzed, prepare one glass slide with about 5 Pap-pen wells of 2 mm squares each, corresponding to the field viewing area of the microscope; add approximately 5 – 10 µl of S2 media to each (Figure 1A). Keep slides in a moist chamber to prevent wells from drying out. Option 2 for microscopes with tile scanning function…
Representative Results
Figure 1. Hemocyte Bleed/Scrape and Disturbance Assay setup and schematic. (A) Single Image Slide Setup: five 2mm squares for imaging with a 5X objective. (B) Tile Scan Slide Setup: four 3 mm squares for imaging bleed/scrapes of ≤2.5 mm larvae with a tile scan microscope. Recommended objectives for imaging are 5X or 10X. (C) Bleed/S…
Disclosures
The authors have nothing to disclose.
Materials
| 6cm/9cm Petri dishes | One for each genotype to be evaluated | ||
| Water squirt bottle | |||
| Metal spoon/spatula | |||
| Thin paintbrush | e.g. a "liner" | ||
| Glass cavity dish | |||
| PAP pen: Super PAP PEN IM3580 | Beckman Coulter | ||
| Glass slides | Each slide will have 5 or more PAP PEN squares drawn on them. Size of squares depends on the imaging objective and magnification of the microscope camera; e.g. 2mm squares. | ||
| Moist chamber | This will be used to prevent slides and wells from drying out: sealed container with wet paper towels lining the sides/bottom | ||
| Schneider's Drosophila cell culture media | Invitrogen | ||
| Cold block | This is a metal block (a.k.a. heating block) chilled in bucket containing ice; preferably black-colored or other dark, non-reflective color | ||
| Two 1ml syringes with needles (27G ½) | Becton Dickinson | For dissections. | |
| Optional: Surgical spring scissors (cutting edge 2mm) | Fine Science Tools | ||
| Glass beads, 212-600 micron | Sigma | ||
| 2 ml Eppendorf tubes | Eppendorf | One per genotype evaluating | |
| Vortex Mixer | Fisher Scientific | ||
| Transgenic Drosophila larvae with fluorescently marked hemocytes. Suitable transgenes include: HmlΔ-DsRed (Makhijani et al., 2011), MSNF9mo-mCherry (Tokusumi et al., 2009), BcF6-CFP and -GFP (Gajewski et al., 2007), or HmlΔ-GAL4 (Sinenko and Mathey-Prevot, 2004), Pxn-GAL4 (Stramer et al., 2005), He-GAL4 (Zettervall et al., 2004), Crq-GAL4 (by H. Agaisse (Stramer et al., 2005)), or eater-GAL4 (Tokusumi et al., 2009) combined with UAS-GFP or other fluorescent protein transgenes. | |||
| Fluorescence dissecting microscope | Leica | Here: Leica M205, optional with camera, imaging software and measuring module | |
| Inverted fluorescence microscope with camera attachment | Leica or Keyence | With or without tile scanning function (eg. Leica DMI series, Keyence BIOREVO BZ-9000 series) |
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Cite This Article
A Hemocyte Disturbance Assay to Assess Hemocyte Re-Adhesion to Hematopoietic Pockets. J. Vis. Exp. (Pending Publication), e21920, doi: (2024).